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Conserved domains on  [gi|299735257|gb|ADJ37108|]
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taste receptor type 1 member 2, partial [Murina leucogaster]

Protein Classification

G protein-coupled receptor family protein( domain architecture ID 705710)

G protein-coupled receptor family protein is a seven-transmembrane G protein-coupled receptor (7TM-GPCR) family protein which typically transmits an extracellular signal into the cell by the conformational rearrangement of the 7TM helices and by the subsequent binding and activation of an intracellular heterotrimeric G protein; GPCR ligands include light-sensitive compounds, odors, pheromones, hormones, and neurotransmitters

Graphical summary

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List of domain hits

Name Accession Description Interval E-value
7tm_GPCRs super family cl28897
seven-transmembrane G protein-coupled receptor superfamily; This hierarchical evolutionary ...
9-237 2.86e-124

seven-transmembrane G protein-coupled receptor superfamily; This hierarchical evolutionary model represents the seven-transmembrane (7TM) receptors, often referred to as G protein-coupled receptors (GPCRs), which transmit physiological signals from the outside of the cell to the inside via G proteins. GPCRs constitute the largest known superfamily of transmembrane receptors across the three kingdoms of life that respond to a wide variety of extracellular stimuli including peptides, lipids, neurotransmitters, amino acids, hormones, and sensory stimuli such as light, smell and taste. All GPCRs share a common structural architecture comprising of seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops. A general feature of GPCR signaling is agonist-induced conformational changes in the receptors, leading to activation of the heterotrimeric G proteins, which consist of the guanine nucleotide-binding G-alpha subunit and the dimeric G-beta-gamma subunits. The activated G proteins then bind to and activate numerous downstream effector proteins, which generate second messengers that mediate a broad range of cellular and physiological processes. However, some 7TM receptors, such as the type 1 microbial rhodopsins, do not activate G proteins. Based on sequence similarity, GPCRs can be divided into six major classes: class A (the rhodopsin-like family), class B (the Methuselah-like, adhesion and secretin-like receptor family), class C (the metabotropic glutamate receptor family), class D (the fungal mating pheromone receptors), class E (the cAMP receptor family), and class F (the frizzled/smoothened receptor family). Nearly 800 human GPCR genes have been identified and are involved essentially in all major physiological processes. Approximately 40% of clinically marketed drugs mediate their effects through modulation of GPCR function for the treatment of a variety of human diseases including bacterial infections.


The actual alignment was detected with superfamily member cd15288:

Pssm-ID: 475119  Cd Length: 254  Bit Score: 352.55  E-value: 2.86e-124
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd15288    1 GPTIVVALLAALGFLSTLAILVIFGRHFQTPVVRSAGGRMCFLMLAPLLVAYVNVPVYVGIPTVFTCLCRQTLFPLCFTV 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVFKVARRFPRAYGYWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPNVMILSCNPN 168
Cdd:cd15288   81 CISCIAVRSFQIVCIFKMARRLPRAYSYWVKYNGPYVFVALITLLKVVIVVINVLAHPTAPTTRADPDDPQVMILQCNPN 160
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 299735257 169 YRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFITLCTVMSVYDGVLVTFLD 237
Cdd:cd15288  161 YRLALLFNTSLDLLLSVLGFCFAYMGKELPTNYNEAKFITLCMTFYFASSVFLCTFMSVYEGVLVTIFD 229
 
Name Accession Description Interval E-value
7tmC_TAS1R2 cd15288
type 1 taste receptor subtype 2, member of the class C of seven-transmembrane G ...
9-237 2.86e-124

type 1 taste receptor subtype 2, member of the class C of seven-transmembrane G protein-coupled receptors; This group represents TAS1R2, which is a member of the type I taste receptor (TAS1R) family that belongs to the class C of G protein-coupled receptors. The functional TAS1Rs are obligatory heterodimers built from three known members, TAS1R1-3. TAS1R1 combines with TAS1R3 to form an umami taste receptor, which is responsible for the perception of savory taste, such as the food additive mono-sodium glutamate (MSG); whereas the combination of TAS1R2-TAS1R3 forms a sweet-taste receptor for sugars and D-amino acids. On the other hand, the type II taste receptors (TAS2Rs), which belong to the class A family of GPCRs, recognize bitter tasting compounds. In the case of sweet, for example, the TAS1R2-TAS1R3 heterodimer activates phospholipase C (PLC) via alpha-gustducin, a heterodimeric G protein that is involved in perception of sweet and bitter tastes. This activation leads to generation of inositol (1, 4, 5)-trisphosphate (IP3) and diacylglycerol (DAG), and consequently increases intracellular Ca2+ mobilization and activates a cation channel, TRPM5. In contrast to the TAS1R2-TAS1R3 heterodimer, TAS1R3 alone could activate adenylate cyclase leading to cAMP formation in the absence of alpha-gustducin. Each TAS1R contains a large extracellular Venus flytrap-like domain in the N-terminus, cysteine-rich domain (CRD) and seven-transmembrane (7TM) domain, which are characteristics of the class C GPCRs. The Venus flytrap-like domain shares strong sequence homology to bacterial periplasmic binding proteins and possess the orthosteric amino acid and calcium binding sites for members of the class C, including CaSR, GABA-B1, GPRC6A, mGlu, and TAS1R receptors.


Pssm-ID: 320415  Cd Length: 254  Bit Score: 352.55  E-value: 2.86e-124
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd15288    1 GPTIVVALLAALGFLSTLAILVIFGRHFQTPVVRSAGGRMCFLMLAPLLVAYVNVPVYVGIPTVFTCLCRQTLFPLCFTV 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVFKVARRFPRAYGYWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPNVMILSCNPN 168
Cdd:cd15288   81 CISCIAVRSFQIVCIFKMARRLPRAYSYWVKYNGPYVFVALITLLKVVIVVINVLAHPTAPTTRADPDDPQVMILQCNPN 160
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 299735257 169 YRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFITLCTVMSVYDGVLVTFLD 237
Cdd:cd15288  161 YRLALLFNTSLDLLLSVLGFCFAYMGKELPTNYNEAKFITLCMTFYFASSVFLCTFMSVYEGVLVTIFD 229
7tm_3 pfam00003
7 transmembrane sweet-taste receptor of 3 GCPR; This is a domain of seven transmembrane ...
4-228 4.29e-39

7 transmembrane sweet-taste receptor of 3 GCPR; This is a domain of seven transmembrane regions that forms the C-terminus of some subclass 3 G-coupled-protein receptors. It is often associated with a downstream cysteine-rich linker domain, NCD3G pfam07562, which is the human sweet-taste receptor, and the N-terminal domain, ANF_receptor pfam01094. The seven TM regions assemble in such a way as to produce a docking pocket into which such molecules as cyclamate and lactisole have been found to bind and consequently confer the taste of sweetness.


Pssm-ID: 459626 [Multi-domain]  Cd Length: 247  Bit Score: 135.48  E-value: 4.29e-39
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257    4 LEWHNALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTIsTCLCRQAFFN 83
Cdd:pfam00003   1 LDLSAPWGIVLEALAALGILLTLVLLVVFLLHRKTPIVKASNRSLSFLLLLGLLLLFLLAFLFIGKPTV-TCALRRFLFG 79
                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   84 LCFTICISCITVRSFQIVCVFKVARRFPRAYGYwvryhgpYVFVAAITAFKVAIVTVNQLVTptgPTARANPEDPNVMIL 163
Cdd:pfam00003  80 VGFTLCFSCLLAKTFRLVLIFRRRKPGPRGWQL-------LLLALGLLLVQVIILTEWLIDP---PFPEKDNLSEGKIIL 149
                         170       180       190       200       210       220
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 299735257  164 SCNPNYRKGLL-VNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFITLCTVMSVY 228
Cdd:pfam00003 150 ECEGSTSIAFLdFVLAYVGLLLLAGFLLAFKTRKLPDNFNEAKFITFSMLLSVLIWVAFIPMYLYG 215
 
Name Accession Description Interval E-value
7tmC_TAS1R2 cd15288
type 1 taste receptor subtype 2, member of the class C of seven-transmembrane G ...
9-237 2.86e-124

type 1 taste receptor subtype 2, member of the class C of seven-transmembrane G protein-coupled receptors; This group represents TAS1R2, which is a member of the type I taste receptor (TAS1R) family that belongs to the class C of G protein-coupled receptors. The functional TAS1Rs are obligatory heterodimers built from three known members, TAS1R1-3. TAS1R1 combines with TAS1R3 to form an umami taste receptor, which is responsible for the perception of savory taste, such as the food additive mono-sodium glutamate (MSG); whereas the combination of TAS1R2-TAS1R3 forms a sweet-taste receptor for sugars and D-amino acids. On the other hand, the type II taste receptors (TAS2Rs), which belong to the class A family of GPCRs, recognize bitter tasting compounds. In the case of sweet, for example, the TAS1R2-TAS1R3 heterodimer activates phospholipase C (PLC) via alpha-gustducin, a heterodimeric G protein that is involved in perception of sweet and bitter tastes. This activation leads to generation of inositol (1, 4, 5)-trisphosphate (IP3) and diacylglycerol (DAG), and consequently increases intracellular Ca2+ mobilization and activates a cation channel, TRPM5. In contrast to the TAS1R2-TAS1R3 heterodimer, TAS1R3 alone could activate adenylate cyclase leading to cAMP formation in the absence of alpha-gustducin. Each TAS1R contains a large extracellular Venus flytrap-like domain in the N-terminus, cysteine-rich domain (CRD) and seven-transmembrane (7TM) domain, which are characteristics of the class C GPCRs. The Venus flytrap-like domain shares strong sequence homology to bacterial periplasmic binding proteins and possess the orthosteric amino acid and calcium binding sites for members of the class C, including CaSR, GABA-B1, GPRC6A, mGlu, and TAS1R receptors.


Pssm-ID: 320415  Cd Length: 254  Bit Score: 352.55  E-value: 2.86e-124
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd15288    1 GPTIVVALLAALGFLSTLAILVIFGRHFQTPVVRSAGGRMCFLMLAPLLVAYVNVPVYVGIPTVFTCLCRQTLFPLCFTV 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVFKVARRFPRAYGYWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPNVMILSCNPN 168
Cdd:cd15288   81 CISCIAVRSFQIVCIFKMARRLPRAYSYWVKYNGPYVFVALITLLKVVIVVINVLAHPTAPTTRADPDDPQVMILQCNPN 160
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 299735257 169 YRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFITLCTVMSVYDGVLVTFLD 237
Cdd:cd15288  161 YRLALLFNTSLDLLLSVLGFCFAYMGKELPTNYNEAKFITLCMTFYFASSVFLCTFMSVYEGVLVTIFD 229
7tmC_TAS1R cd15046
type 1 taste receptors, member of the class C of seven-transmembrane G protein-coupled ...
9-237 8.55e-88

type 1 taste receptors, member of the class C of seven-transmembrane G protein-coupled receptors; This subfamily represents the type I taste receptors (TAS1Rs) that belongs to the class C family of G protein-coupled receptors. The functional TAS1Rs are obligatory heterodimers built from three known members, TAS1R1-3. TAS1R1 combines with TAS1R3 to form an umami taste receptor, which is responsible for the perception of savory taste, such as the food additive mono-sodium glutamate (MSG); whereas the combination of TAS1R2-TAS1R3 forms a sweet-taste receptor for sugars and D-amino acids. On the other hand, the type II taste receptors (TAS2Rs), which belong to the class A family of GPCRs, recognize bitter tasting compounds. In the case of sweet, for example, the TAS1R2-TAS1R3 heterodimer activates phospholipase C (PLC) via alpha-gustducin, a heterodimeric G protein that is involved in perception of sweet and bitter tastes. This activation leads to generation of inositol (1, 4, 5)-trisphosphate (IP3) and diacylglycerol (DAG), and consequently increases intracellular Ca2+ mobilization and activates a cation channel, TRPM5. In contrast to the TAS1R2-TAS1R3 heterodimer, TAS1R3 alone could activate adenylate cyclase leading to cAMP formation in the absence of alpha-gustducin. Each TAS1R contains a large extracellular Venus flytrap-like domain in the N-terminus, cysteine-rich domain (CRD) and seven-transmembrane (7TM) domain, which are characteristics of the class C GPCRs. The Venus flytrap-like domain shares strong sequence homology to bacterial periplasmic binding proteins and possess the orthosteric amino acid and calcium binding sites for members of the class C, including CaSR, GABA-B1, GPRC6A, mGlu, and TAS1R receptors.


Pssm-ID: 320174 [Multi-domain]  Cd Length: 253  Bit Score: 260.15  E-value: 8.55e-88
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd15046    1 APTVAVLLLAALGLLSTLAILVIFWRNFNTPVVRSAGGPMCFLMLTLLLVAYMSVPVYFGPPKVSTCLLRQALFPLCFTV 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVFKVARRFPRAYGYWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPeDPNVMILSCNPN 168
Cdd:cd15046   81 CLACIAVRSFQIVCIFKMASRFPRAYSYWVKYHGPYVSIAFITVLKMVIVVIGMLATPPSPTTDTDP-DPKITIVSCNPN 159
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 299735257 169 YRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFITLCTVMSVYDGVLVTFLD 237
Cdd:cd15046  160 YRNSSLFNTSLDLLLSVVCFSFSYMGKDLPTNYNEAKFITFSLTFYFTSWISFCTFMLAYSGVLVTIVD 228
7tmC_TAS1R1 cd15289
type 1 taste receptor subtype 1, member of the class C of seven-transmembrane G ...
9-230 2.08e-52

type 1 taste receptor subtype 1, member of the class C of seven-transmembrane G protein-coupled receptors; This group represents TAS1R1, which is a member of the type I taste receptor (TAS1R) family that belongs to the class C of G protein-coupled receptors. The functional TAS1Rs are obligatory heterodimers built from three known members, TAS1R1-3. TAS1R1 combines with TAS1R3 to form an umami taste receptor, which is responsible for the perception of savory taste, such as the food additive mono-sodium glutamate (MSG); whereas the combination of TAS1R2-TAS1R3 forms a sweet-taste receptor for sugars and D-amino acids. On the other hand, the type II taste receptors (TAS2Rs), which belong to the class A family of GPCRs, recognize bitter tasting compounds. In the case of sweet, for example, the TAS1R2-TAS1R3 heterodimer activates phospholipase C (PLC) via alpha-gustducin, a heterodimeric G protein that is involved in perception of sweet and bitter tastes. This activation leads to generation of inositol (1, 4, 5)-trisphosphate (IP3) and diacylglycerol (DAG), and consequently increases intracellular Ca2+ mobilization and activates a cation channel, TRPM5. In contrast to the TAS1R2-TAS1R3 heterodimer, TAS1R3 alone could activate adenylate cyclase leading to cAMP formation in the absence of alpha-gustducin. Each TAS1R contains a large extracellular Venus flytrap-like domain in the N-terminus, cysteine-rich domain (CRD) and seven-transmembrane (7TM) domain, which are characteristics of the class C GPCRs. The Venus flytrap-like domain shares strong sequence homology to bacterial periplasmic binding proteins and possess the orthosteric amino acid and calcium binding sites for members of the class C, including CaSR, GABA-B1, GPRC6A, mGlu, and TAS1R receptors.


Pssm-ID: 320416  Cd Length: 253  Bit Score: 169.91  E-value: 2.08e-52
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLaalgFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd15289    5 ALLTALTLL----LLLLAGTALLFALNLTTPVVKSAGGRTCFLMLGSLAAASCSLYCHFGEPTWLACLLKQPLFSLSFTV 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVFKVARRFPRAYGYWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANpEDPNVMILSCNPN 168
Cdd:cd15289   81 CLSCIAVRSFQIVCIFKLASKLPRFYETWAKNHGPELFILISSAVQLLISLLWLVLNPPVPTKDYD-RYPDLIVLECSQT 159
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 299735257 169 YRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFITLCTVMSVYDG 230
Cdd:cd15289  160 LSVGSFLELLYNCLLSISCFVFSYMGKDLPANYNEAKCITFSLLIYFISWISFFTTYSIYRG 221
7tmC_TAS1R2a-like cd15287
type 1 taste receptor subtype 2a and similar proteins, member of the class C of ...
9-237 9.26e-45

type 1 taste receptor subtype 2a and similar proteins, member of the class C of seven-transmembrane G protein-coupled receptors; This group includes TAS1R2a and its similar proteins found in fish. They are members of the type I taste receptor (TAS1R) family that belongs to the class C of G protein-coupled receptors. The functional TAS1Rs are obligatory heterodimers built from three known members, TAS1R1-3. TAS1R1 combines with TAS1R3 to form an umami taste receptor, which is responsible for the perception of savory taste, such as the food additive mono-sodium glutamate (MSG); whereas the combination of TAS1R2-TAS1R3 forms a sweet-taste receptor for sugars and D-amino acids. On the other hand, the type II taste receptors (TAS2Rs), which belong to the class A family of GPCRs, recognize bitter tasting compounds. In the case of sweet, for example, the TAS1R2-TAS1R3 heterodimer activates phospholipase C (PLC) via alpha-gustducin, a heterodimeric G protein that is involved in perception of sweet and bitter tastes. This activation leads to generation of inositol (1, 4, 5)-trisphosphate (IP3) and diacylglycerol (DAG), and consequently increases intracellular Ca2+ mobilization and activates a cation channel, TRPM5. In contrast to the TAS1R2-TAS1R3 heterodimer, TAS1R3 alone could activate adenylate cyclase leading to cAMP formation in the absence of alpha-gustducin. Each TAS1R contains a large extracellular Venus flytrap-like domain in the N-terminus, cysteine-rich domain (CRD) and seven-transmembrane (7TM) domain, which are characteristics of the class C GPCRs. The Venus flytrap-like domain shares strong sequence homology to bacterial periplasmic binding proteins and possess the orthosteric amino acid and calcium binding sites for members of the class C, including CaSR, GABA-B1, GPRC6A, mGlu, and TAS1R receptors.


Pssm-ID: 320414  Cd Length: 252  Bit Score: 150.22  E-value: 9.26e-45
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFlsTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd15287    3 AILIMVGACVLVGL--TLAVSVLFAINYNTPVVRSAGGPMCFLILGCLSLCSVSVFFYFGKPTVASCILRYFPFLLFYTV 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVFKVARRFPRAYGYWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTaRANPEDPNVMILSCNPN 168
Cdd:cd15287   81 CLACFVVRSFQIVCIFKIAAKFPKLHSWWVKYHGQWLLIAVAFVIQALLLITGFSFSPPKPY-NDTSWYPDKIILSCDIN 159
                        170       180       190       200       210       220       230
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 299735257 169 YRKgllVNTSLDLLLSVAG--FSFAYMGKELPTNYNEAKFITFCMTFYFTSFITLCTVMSVYDGVLVTFLD 237
Cdd:cd15287  160 LKA---TSMSLVLLLSLCClcFIFSYMGKDLPKNYNEAKAITFCLLLLILTWIIFATEYMLYRGKYIQLLN 227
7tm_3 pfam00003
7 transmembrane sweet-taste receptor of 3 GCPR; This is a domain of seven transmembrane ...
4-228 4.29e-39

7 transmembrane sweet-taste receptor of 3 GCPR; This is a domain of seven transmembrane regions that forms the C-terminus of some subclass 3 G-coupled-protein receptors. It is often associated with a downstream cysteine-rich linker domain, NCD3G pfam07562, which is the human sweet-taste receptor, and the N-terminal domain, ANF_receptor pfam01094. The seven TM regions assemble in such a way as to produce a docking pocket into which such molecules as cyclamate and lactisole have been found to bind and consequently confer the taste of sweetness.


Pssm-ID: 459626 [Multi-domain]  Cd Length: 247  Bit Score: 135.48  E-value: 4.29e-39
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257    4 LEWHNALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTIsTCLCRQAFFN 83
Cdd:pfam00003   1 LDLSAPWGIVLEALAALGILLTLVLLVVFLLHRKTPIVKASNRSLSFLLLLGLLLLFLLAFLFIGKPTV-TCALRRFLFG 79
                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   84 LCFTICISCITVRSFQIVCVFKVARRFPRAYGYwvryhgpYVFVAAITAFKVAIVTVNQLVTptgPTARANPEDPNVMIL 163
Cdd:pfam00003  80 VGFTLCFSCLLAKTFRLVLIFRRRKPGPRGWQL-------LLLALGLLLVQVIILTEWLIDP---PFPEKDNLSEGKIIL 149
                         170       180       190       200       210       220
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 299735257  164 SCNPNYRKGLL-VNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFITLCTVMSVY 228
Cdd:pfam00003 150 ECEGSTSIAFLdFVLAYVGLLLLAGFLLAFKTRKLPDNFNEAKFITFSMLLSVLIWVAFIPMYLYG 215
7tm_classC_mGluR-like cd13953
metabotropic glutamate receptor-like class C family of seven-transmembrane G protein-coupled ...
9-236 3.17e-37

metabotropic glutamate receptor-like class C family of seven-transmembrane G protein-coupled receptors superfamily; The class C GPCRs consist of glutamate receptors (mGluR1-8), the extracellular calcium-sensing receptors (caSR), the gamma-amino-butyric acid type B receptors (GABA-B), the vomeronasal type-2 pheromone receptors (V2R), the type 1 taste receptors (TAS1R), and the promiscuous L-alpha-amino acid receptor (GPRC6A), as well as several orphan receptors. Structurally, these receptors are typically composed of a large extracellular domain containing a Venus flytrap module which possesses the orthosteric agonist-binding site, a cysteine-rich domain (CRD) with the exception of GABA-B receptors, and the seven-transmembrane domains responsible for G protein activation. Moreover, the Venus flytrap module shows high structural homology with bacterial periplasmic amino acid-binding proteins, which serve as primary receptors in transport of a variety of soluble substrates such as amino acids and polysaccharides, among many others. The class C GPCRs exist as either homo- or heterodimers, which are essential for their function. The GABA-B1 and GABA-B2 receptors form a heterodimer via interactions between the N-terminal Venus flytrap modules and the C-terminal coiled-coiled domains. On the other hand, heterodimeric CaSRs and Tas1Rs and homodimeric mGluRs utilize Venus flytrap interactions and intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD), which can also acts as a molecular link to mediate the signal between the Venus flytrap and the 7TMs. Furthermore, members of the class C GPCRs bind a variety of endogenous ligands, ranging from amino acids, ions, to pheromones and sugar molecules, and play important roles in many physiological processes such as synaptic transmission, calcium homeostasis, and the sensation of sweet and umami tastes.


Pssm-ID: 320091 [Multi-domain]  Cd Length: 251  Bit Score: 130.82  E-value: 3.17e-37
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd13953    1 PLAIVLLVLAALGLLLTIFIWVVFIRYRNTPVVKASNRELSYLLLFGILLCFLLAFLFLLPPSDVLCGLRRFLFGLSFTL 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVFKVARRfPRAYGYWVRYHGPYVFVAAITAFKVAIVTVNQLVTPtgPTARANPEDPNVMILSCNPN 168
Cdd:cd13953   81 VFSTLLVKTNRIYRIFKSGLR-SSLRPKLLSNKSQLLLVLFLLLVQVAILIVWLILDP--PKVEKVIDSDNKVVELCCST 157
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 299735257 169 YRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFITLCTVMSVYDGVLVTFL 236
Cdd:cd13953  158 GNIGLILSLVYNILLLLICTYLAFKTRKLPDNFNEARYIGFSSLLSLVIWIAFIPTYFTTSGPYRDAI 225
7tmC_GPRC6A cd15281
class C of seven-transmembrane G protein-coupled receptors, subtype 6A; GRPC6A (GPCR, class C, ...
10-233 2.93e-31

class C of seven-transmembrane G protein-coupled receptors, subtype 6A; GRPC6A (GPCR, class C, group 6, subtype A) is a widely expressed amino acid-sensing GPCR that is most closely related to CaSR. GPRC6A is most potently activated by the basic amino acids L-arginine, L-lysine, and L-ornithine and less potently by small aliphatic amino acids. Moreover, the receptor can be either activated or modulated by divalent cations such as Ca2+ and Mg2+. GPRC6A is expressed in the testis, but not the ovary and specifically also binds to the osteoblast-derived hormone osteocalcin (OCN), which regulates testosterone production by the testis and male fertility independently of the hypothalamic-pituitary axis. Furthermore, GPRC6A knockout studies suggest that GRPC6A is involved in regulation of bone metabolism, male reproduction, energy homeostasis, glucose metabolism, and in activation of inflammation response, as well as prostate cancer growth and progression, among others. GPRC6A has been suggested to couple to the Gq subtype of G proteins, leading to IP3 production and intracellular calcium mobilization. GPRC6A contains a large extracellular Venus flytrap-like domain in the N-terminus, cysteine-rich domain (CRD), and seven-transmembrane (7TM) domain, which are characteristics of the class C GPCRs. The Venus flytrap-like domain shares strong sequence homology to bacterial periplasmic binding proteins and possess the orthosteric amino acid and calcium binding sites for members of the class C, including CaSR, GABA-B, GPRC6A, mGlu, and TAS1R receptors.


Pssm-ID: 320408  Cd Length: 249  Bit Score: 115.26  E-value: 2.93e-31
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  10 LTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTIC 89
Cdd:cd15281    2 FAIVLLILSALGVLLIFFISALFTKNLNTPVVKAGGGPLCYVILLSHFGSFISTVFFIGEPSDLTCKTRQTLFGISFTLC 81
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  90 ISCITVRSFQIVCVFKVArrfPRAYGYWVRYHGPYVFVAAITAFKVAIVTVNQLVTPtgPTARANPEDPNVMILSCNPNY 169
Cdd:cd15281   82 VSCILVKSLKILLAFSFD---PKLQELLKCLYKPIMIVFICTGIQVIICTVWLVFYK--PFVDKNFSLPESIILECNEGS 156
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 299735257 170 RKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFITLCTVMSVYDGVLV 233
Cdd:cd15281  157 YVAFGLMLGYIALLAFICFIFAFKGRKLPENYNEAKFITFGMLIYFIAWITFIPIYATTFGKYV 220
7tmC_V2R_pheromone cd15283
vomeronasal type-2 pheromone receptors, member of the class C family of seven-transmembrane G ...
10-211 3.95e-25

vomeronasal type-2 pheromone receptors, member of the class C family of seven-transmembrane G protein-coupled receptors; This group represents vomeronasal type-2 pheromone receptors (V2Rs). Members of the V2R family of vomeronasal GPCRs are involved in detecting protein pheromones for social and sexual cues between the same species. V2Rs and G-alpha(o) protein are coexpressed in the basal layer of the vomeronasal organ (VNO), which is the sensory organ of the accessory olfactory system present in amphibians, reptiles, and non-primate mammals such as mice and rodents, but it is non-functional or absent in humans, apes, and monkeys. On the other hand, members of the V1R receptor family and G-alpha(i2) protein are coexpressed in the apical neurons of the VNO. Activation of V1R or V2R causes activation of phospholipase pathway, producing the second messengers diacylglycerol (DAG) and IP3. However, in contrast to V1Rs, V2Rs contain the long N-terminal extracellular domain, which is believed to bind pheromones.


Pssm-ID: 320410 [Multi-domain]  Cd Length: 252  Bit Score: 99.27  E-value: 3.95e-25
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  10 LTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTIC 89
Cdd:cd15283    2 LGIALTVLSLLGSVLTAAVLVVFIKHRDTPIVKANNSELSYLLLLSLKLCFLCSLLFIGQPSTWTCMLRQTAFGISFVLC 81
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  90 ISCITVRSFQIVCVFKVARrfPRAYG-YWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPNVmILSCNpn 168
Cdd:cd15283   82 ISCILAKTIVVVAAFKATR--PGSNImKWFGPGQQRAIIFICTLVQVVICAIWLATSPPFPDKNMHSEHGKI-ILECN-- 156
                        170       180       190       200
                 ....*....|....*....|....*....|....*....|....*..
gi 299735257 169 yrKGLLVNTSLDL----LLSVAGFSFAYMGKELPTNYNEAKFITFCM 211
Cdd:cd15283  157 --EGSVVAFYCVLgyigLLALVSFLLAFLARKLPDNFNEAKFITFSM 201
7tmC_V2R_AA_sensing_receptor-like cd15044
vomeronasal type-2 pheromone receptors, amino acid-sensing receptors and closely related ...
9-220 1.36e-24

vomeronasal type-2 pheromone receptors, amino acid-sensing receptors and closely related proteins; member of the class C family of seven-transmembrane G protein-coupled receptors; This group is composed of vomeronasal type-2 pheromone receptors (V2Rs), a subgroup of broad-spectrum amino-acid sensing receptors including calcium-sensing receptor (CaSR) and GPRC6A, as well as their closely related proteins. Members of the V2R family of vomeronasal GPCRs are involved in detecting protein pheromones for social and sexual cues between the same species. V2Rs and G-alpha(o) protein are co-expressed in the basal layer of the vomeronasal organ (VNO), which is the sensory organ of the accessory olfactory system present in amphibians, reptiles, and non-primate mammals such as mice and rodents, but it is non-functional or absent in humans, apes, and monkeys. On the other hand, members of the V1R receptor family and G-alpha(i2) protein are co-expressed in the apical neurons of the VNO. Activation of V1R or V2R causes activation of phospholipase pathway, producing the second messengers diacylglycerol (DAG) and IP3. However, in contrast to V1Rs, V2Rs contain the long N-terminal extracellular domain, which is believed to bind pheromones. CaSR is a widely expressed GPCR that is involved in sensing small changes in extracellular levels of calcium ion to maintain a constant level of the extracellular calcium via modulating the synthesis and secretion of calcium regulating hormones, such as parathyroid hormone (PTH), in order to regulate Ca(2+)transport into or out of the extracellular fluid via kidney, intestine, and/or bone. For instance, when Ca2+ is high, CaSR downregulates PTH synthesis and secretion, leading to an increase in renal Ca2+ excretion, a decrease in intestinal Ca2+ absorption, and a reduction in release of skeletal Ca2+. GRPC6A (GPCR, class C, group 6, subtype A) is a widely expressed amino acid-sensing GPCR that is most closely related to CaSR. GPRC6A is most potently activated by the basic amino acids L-arginine, L-lysine, and L-ornithine and less potently by small aliphatic amino acids. Moreover, the receptor can be either activated or modulated by divalent cations such as Ca2+. GPRC6A is expressed in the testis, but not the ovary and specifically also binds to the osteoblast-derived hormone osteocalcin (OCN), which regulates testosterone production by the testis and male fertility independently of the hypothalamic-pituitary axis. Furthermore, GPRC6A knockout studies suggest that GRPC6A is involved in regulation of bone metabolism, male reproduction, energy homeostasis, glucose metabolism, and in activation of inflammation response, as well as prostate cancer growth and progression, among others.


Pssm-ID: 320172 [Multi-domain]  Cd Length: 251  Bit Score: 97.92  E-value: 1.36e-24
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd15044    1 PLGILLVILSILGIIFVLVVGGVFVRYRNTPIVKANNRELSYLILLSLFLCFSSSLFFIGEPQDWTCKLRQTMFGVSFTL 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVFKVARRFPRAYGYWVRYhgPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEdPNVMILSCNPN 168
Cdd:cd15044   81 CISCILTKTLKVLLAFSADKPLTQKFLMCLYL--PILIVFTCTGIQVVICTVWLIFAPPTVEVNVSPL-PRVIILECNEG 157
                        170       180       190       200       210
                 ....*....|....*....|....*....|....*....|....*....|..
gi 299735257 169 YRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFIT 220
Cdd:cd15044  158 SILAFGTMLGYIAFLAFLCFLFAFKARKLPDNYNEAKFITFGMLVFFIVWIS 209
7tmC_mGluR2 cd15447
metabotropic glutamate receptor 2 in group 2, member of the class C family of ...
15-221 2.83e-22

metabotropic glutamate receptor 2 in group 2, member of the class C family of seven-transmembrane G protein-coupled receptors; The metabotropic glutamate receptors (mGluRs) in group 2 include mGluR 2 and 3. They are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group 1 mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to G(i/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320563  Cd Length: 254  Bit Score: 91.53  E-value: 2.83e-22
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  15 VLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICISCIT 94
Cdd:cd15447    7 VTISCLGILSTLFVVGVFVKNNETPVVKASGRELCYILLLGVLLCYLMTFIFIAKPSTAVCTLRRLGLGTSFAVCYSALL 86
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  95 VRSFQIVCVFKVAR---RFPRaygyWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPNVMILSCNpNYRK 171
Cdd:cd15447   87 TKTNRIARIFSGAKdgaQRPR----FISPASQVAICLALISCQLLVVLIWLLVEAPGTRKETAPERRYVVTLKCN-SRDS 161
                        170       180       190       200       210
                 ....*....|....*....|....*....|....*....|....*....|
gi 299735257 172 GLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMtfYFTSFITL 221
Cdd:cd15447  162 SMLISLTYNVLLIILCTLYAFKTRKCPENFNEAKFIGFTM--YTTCIIWL 209
7tmC_mGluRs cd15045
metabotropic glutamate receptors, member of the class C family of seven-transmembrane G ...
12-219 2.50e-20

metabotropic glutamate receptors, member of the class C family of seven-transmembrane G protein-coupled receptors; The metabotropic glutamate receptors (mGluRs) are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group I mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to (Gi/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320173 [Multi-domain]  Cd Length: 253  Bit Score: 86.53  E-value: 2.50e-20
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  12 IFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICIS 91
Cdd:cd15045    4 IGAMAFASLGILLTLFVLVVFVRYRDTPVVKASGRELSYVLLAGILLSYVMTFVLVAKPSTIVCGLQRFGLGLCFTVCYA 83
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  92 CITVRSFQIVCVFKVARRFPRAYGYwVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPNVmiLSCNPNYRK 171
Cdd:cd15045   84 AILTKTNRIARIFRLGKKSAKRPRF-ISPRSQLVITGLLVSVQVLVLAVWLILSPPRATHHYPTRDKNV--LVCSSALDA 160
                        170       180       190       200
                 ....*....|....*....|....*....|....*....|....*...
gi 299735257 172 GLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMtfyFTSFI 219
Cdd:cd15045  161 SYLIGLAYPILLIILCTVYAFKTRKIPEGFNEAKYIGFTM---YTTCI 205
7tmC_V2R-like cd15280
vomeronasal type-2 receptor-like proteins, member of the class C family of seven-transmembrane ...
9-220 1.08e-19

vomeronasal type-2 receptor-like proteins, member of the class C family of seven-transmembrane G protein-coupled receptors; This group represents vomeronasal type-2 receptor-like proteins that are closely related to the V2R family of vomeronasal GPCRs. Members of the V2R family of vomeronasal GPCRs are involved in detecting protein pheromones for social and sexual cues between the same species. V2Rs and G-alpha(o) protein are coexpressed in the basal layer of the vomeronasal organ (VNO), which is the sensory organ of the accessory olfactory system present in amphibians, reptiles, and non-primate mammals such as mice and rodents, but it is non-functional or absent in humans, apes, and monkeys. On the other hand, members of the V1R receptor family and G-alpha(i2) protein are co-expressed in the apical neurons of the VNO. Activation of V1R or V2R causes activation of phospholipase pathway, generating the secondary messengers diacylglycerol (DAG) and IP3. However, in contrast to V1Rs, V2Rs contain the long N-terminal extracellular domain, which is believed to bind pheromones. Human V2R1-like protein, also known as putative calcium-sensing receptor-like 1 (CASRL1), is not included here because it is a nonfunctional pseudogene.


Pssm-ID: 320407 [Multi-domain]  Cd Length: 253  Bit Score: 84.84  E-value: 1.08e-19
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd15280    1 ALGITLIALSIFGALVVLAVTVVYIMHRHTPLVKANDRELSFLIQMSLVITFLTSILFIGKPENWSCMARQITLALGFSL 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVFKVARRFPRAYGYWVRYHGPYVFVAAITafKVAIVTVNQLVTPtgPTARANPEDPNV-MILSCNP 167
Cdd:cd15280   81 CLSSILGKTISLFLRYRASKSETRLDSMHPIYQKIIVLICVLI--EVGICTAYLILEP--PRMYKNTEVQNVkIIFECNE 156
                        170       180       190       200       210
                 ....*....|....*....|....*....|....*....|....*....|...
gi 299735257 168 NYRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFIT 220
Cdd:cd15280  157 GSIEFLCSIFGFDVFLALLCFLTAFVARKLPDNFNEGKFITFGMLVFFIVWIS 209
7tmC_mGluRs_group2_3 cd15934
metabotropic glutamate receptors in group 2 and 3, member of the class C family of ...
15-211 2.25e-19

metabotropic glutamate receptors in group 2 and 3, member of the class C family of seven-transmembrane G protein-coupled receptors; The metabotropic glutamate receptors (mGluRs) are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. The mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group I mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to (Gi/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320600  Cd Length: 252  Bit Score: 83.82  E-value: 2.25e-19
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  15 VLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICISCIT 94
Cdd:cd15934    7 VVFALLGILATLFVIVVFIRYNDTPVVKASGRELSYVLLTGILLCYLMTFVLLAKPSVITCALRRLGLGLGFSICYAALL 86
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  95 VRSFQIVCVFKVARRFPRAygywVRYHGP---YVFVAAITAFKVAIVTVNQLVTPtgPTARANPEDPNVMILSCNPNyRK 171
Cdd:cd15934   87 TKTNRISRIFNSGKRSAKR----PRFISPksqLVICLGLISVQLIGVLVWLVVEP--PGTRIDYPRRDQVVLKCKIS-DS 159
                        170       180       190       200
                 ....*....|....*....|....*....|....*....|
gi 299735257 172 GLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCM 211
Cdd:cd15934  160 SLLISLVYNMLLIILCTVYAFKTRKIPENFNEAKFIGFTM 199
7tmC_mGluR_group2 cd15284
metabotropic glutamate receptors in group 2, member of the class C family of ...
9-221 3.19e-19

metabotropic glutamate receptors in group 2, member of the class C family of seven-transmembrane G protein-coupled receptors; The metabotropic glutamate receptors (mGluRs) in group 2 include mGluR 2 and 3. They are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group 1 mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to G(i/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320411  Cd Length: 254  Bit Score: 83.36  E-value: 3.19e-19
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd15284    1 AWAIGPVTIACLGFLCTLFVIGVFIKHNNTPLVKASGRELCYILLFGVFLCYCMTFIFIAKPSPAICTLRRLGLGTSFAV 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVFKVAR---RFPRaygyWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPNVMILSC 165
Cdd:cd15284   81 CYSALLTKTNRIARIFSGVKdgaQRPR----FISPSSQVFICLALISVQLLVVSVWLLVEAPGTRRYTLPEKRETVILKC 156
                        170       180       190       200       210
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 299735257 166 NpNYRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMtfYFTSFITL 221
Cdd:cd15284  157 N-VRDSSMLISLTYDVVLVILCTVYAFKTRKCPENFNEAKFIGFTM--YTTCIIWL 209
7tmC_mGluR_group1 cd15285
metabotropic glutamate receptors in group 1, member of the class C family of ...
11-211 1.50e-18

metabotropic glutamate receptors in group 1, member of the class C family of seven-transmembrane G protein-coupled receptors; Group 1 mGluRs includes mGluR1 and mGluR5, as well as their closely related invertebrate receptors. They are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group 1 mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to G(i/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320412  Cd Length: 250  Bit Score: 81.53  E-value: 1.50e-18
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  11 TIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICI 90
Cdd:cd15285    3 AIVAMVFACVGILATLFVTVVFIRHNDTPVVKASTRELSYIILAGILLCYASTFALLAKPSTISCYLQRILPGLSFAMIY 82
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  91 SCITVRSFQIVCVFKVA-RRFPRAYGYWVRYHGPYVFVAAITAFKVAIVTVNQLVTPtgPTARANPEDPNVMILSCNPNY 169
Cdd:cd15285   83 AALVTKTNRIARILAGSkKKILTRKPRFMSASAQVVITGILISVEVAIIVVMLILEP--PDATLDYPTPKRVRLICNTST 160
                        170       180       190       200
                 ....*....|....*....|....*....|....*....|..
gi 299735257 170 RkGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCM 211
Cdd:cd15285  161 L-GFVVPLGFDFLLILLCTLYAFKTRNLPENFNEAKFIGFTM 201
7tmC_CaSR cd15282
calcium-sensing receptor, member of the class C of seven-transmembrane G protein-coupled ...
12-221 1.20e-17

calcium-sensing receptor, member of the class C of seven-transmembrane G protein-coupled receptors; CaSR is a widely expressed GPCR that is involved in sensing small changes in extracellular levels of calcium ion to maintain a constant level of the extracellular calcium via modulating the synthesis and secretion of calcium regulating hormones, such as parathyroid hormone (PTH), in order to regulate Ca(2+)transport into or out of the extracellular fluid via kidney, intestine, and/or bone. For instance, when Ca2+ is high, CaSR downregulates PTH synthesis and secretion, leading to an increase in renal Ca2+ excretion, a decrease in intestinal Ca2+ absorption, and a reduction in release of skeletal Ca2+. CaSR is coupled to both G(q/11)-dependent activation of phospholipase and, subsequently, intracellular calcium mobilization and protein kinase C activation as well as G(i/o)-dependent inhibition of adenylate cyclase leading to inhibition of cAMP formation. CaSR is closely related to GRPC6A (GPCR, class C, group 6, subtype A), which is an amino acid-sensing GPCR that is most potently activated by the basic amino acids L-arginine, L-lysine, and L-ornithine. These receptors contain a large extracellular Venus flytrap-like domain in the N-terminus, cysteine-rich domain (CRD), and seven-transmembrane (7TM) domain, which are characteristics of the class C GPCRs. The Venus flytrap-like domain shares strong sequence homology to bacterial periplasmic binding proteins and possess the orthosteric amino acid and calcium binding sites for members of the class C, including CaSR, GABA-B1, GPRC6A, mGlu, and TASR1 receptors.


Pssm-ID: 320409 [Multi-domain]  Cd Length: 252  Bit Score: 79.22  E-value: 1.20e-17
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  12 IFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICIS 91
Cdd:cd15282    4 IALTLFAVLGIFLTAFVLGVFIKFRNTPIVKATNRELSYLLLFSLICCFSSSLIFIGEPQDWTCRLRQPAFGISFVLCIS 83
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  92 CITVRSFQIVCVF--KVARRFPRAygyWVRYHGPYVFVAAITAFKVAIVTVNQLVTPtgPTARANPEDPN-VMILSCNPN 168
Cdd:cd15282   84 CILVKTNRVLLVFeaKIPTSLHRK---WWGLNLQFLLVFLCTFVQIVICVIWLYTAP--PSSYRNHELEDeIIFITCNEG 158
                        170       180       190       200       210
                 ....*....|....*....|....*....|....*....|....*....|...
gi 299735257 169 YRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFITL 221
Cdd:cd15282  159 SLMALGFLIGYTCLLAAICFFFAFKSRKLPENFNEAKFITFSMLIFFIVWISF 211
7tmC_mGluR3 cd15448
metabotropic glutamate receptor 3 in group 2, member of the class C family of ...
9-211 1.73e-16

metabotropic glutamate receptor 3 in group 2, member of the class C family of seven-transmembrane G protein-coupled receptors; The metabotropic glutamate receptors (mGluRs) in group 2 include mGluR 2 and 3. They are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group 1 mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to G(i/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320564  Cd Length: 254  Bit Score: 76.14  E-value: 1.73e-16
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTI 88
Cdd:cd15448    1 AWAIGPVTIACLGFICTCMVITVFIKHNNTPLVKASGRELCYILLFGVFLSYCMTFFFIAKPSPVICTLRRLGLGTSFAV 80
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  89 CISCITVRSFQIVCVF---KVARRFPRaygyWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPNVMILSC 165
Cdd:cd15448   81 CYSALLTKTNCIARIFdgvKNGAQRPK----FISPSSQVFICLSLILVQIVVVSVWLILEAPGTRRYTLPEKRETVILKC 156
                        170       180       190       200
                 ....*....|....*....|....*....|....*....|....*.
gi 299735257 166 NPNyRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCM 211
Cdd:cd15448  157 NVK-DSSMLISLTYDVVLVILCTVYAFKTRKCPENFNEAKFIGFTM 201
7tmC_TAS1R3 cd15290
type 1 taste receptor subtype 3, member of the class C of seven-transmembrane G ...
10-220 7.89e-16

type 1 taste receptor subtype 3, member of the class C of seven-transmembrane G protein-coupled receptors; This group represents TAS1R3, which is a member of the type I taste receptor (TAS1R) family that belongs to the class C of G protein-coupled receptors. The functional TAS1Rs are obligatory heterodimers built from three known members, TAS1R1-3. TAS1R1 combines with TAS1R3 to form an umami taste receptor, which is responsible for the perception of savory taste, such as the food additive mono-sodium glutamate (MSG); whereas the combination of TAS1R2-TAS1R3 forms a sweet-taste receptor for sugars and D-amino acids. On the other hand, the type II taste receptors (TAS2Rs), which belong to the class A family of GPCRs, recognize bitter tasting compounds. In the case of sweet, for example, the TAS1R2-TAS1R3 heterodimer activates phospholipase C (PLC) via alpha-gustducin, a heterodimeric G protein that is involved in perception of sweet and bitter tastes. This activation leads to generation of inositol (1, 4, 5)-trisphosphate (IP3) and diacylglycerol (DAG), and consequently increases intracellular Ca2+ mobilization and activates a cation channel, TRPM5. In contrast to the TAS1R2-TAS1R3 heterodimer, TAS1R3 alone could activate adenylate cyclase leading to cAMP formation in the absence of alpha-gustducin. Each TAS1R contains a large extracellular Venus flytrap-like domain in the N-terminus, cysteine-rich domain (CRD) and seven-transmembrane (7TM) domain, which are characteristics of the class C GPCRs. The Venus flytrap-like domain shares strong sequence homology to bacterial periplasmic binding proteins and possess the orthosteric amino acid and calcium binding sites for members of the class C, including CaSR, GABA-B1, GPRC6A, mGlu, and TAS1R receptors.


Pssm-ID: 320417 [Multi-domain]  Cd Length: 253  Bit Score: 74.33  E-value: 7.89e-16
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  10 LTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTIC 89
Cdd:cd15290    2 ESLGLLLLGVLLLVLQCSVGVLFLKHRGTPLVQASGGPLSIFALLSLMGACLSLLLFLGQPSDVVCRLQQPLNALFLTVC 81
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  90 ISCITVRSFQIVCVFKVARRFPrAYGYWVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPNVMILSCNPNY 169
Cdd:cd15290   82 LSTILSISLQIFLVTEFPKCAA-SHLHWLRGPGSWLVVLICCLVQAGLCGWYVQDGPSLSEYDAKMTLFVEVFLRCPVEP 160
                        170       180       190       200       210
                 ....*....|....*....|....*....|....*....|....*....|.
gi 299735257 170 RKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMTFYFTSFIT 220
Cdd:cd15290  161 WLGFGLMHGFNGALALISFMCTFMAQKPLKQYNLARDITFSTLIYCVTWVI 211
7tmC_mGluR6 cd15453
metabotropic glutamate receptor 6 in group 3, member of the class C family of ...
15-224 3.51e-11

metabotropic glutamate receptor 6 in group 3, member of the class C family of seven-transmembrane G protein-coupled receptors; The receptors in group 3 include mGluRs 4, 6, 7, and 8. They are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group 1 mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to G(i/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320569 [Multi-domain]  Cd Length: 273  Bit Score: 61.58  E-value: 3.51e-11
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  15 VLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICISCIT 94
Cdd:cd15453    7 LLLAVLGILATTTVVITFVRFNNTPIVRASGRELSYVLLTGIFLIYAITFLMVAEPGAAVCAFRRLFLGLGTTLSYSALL 86
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  95 VRSFQIVCVFKVARRFPRAYGYwVRYHGPYVFVAAITAFKVAIVTVNQLVTPtgPTARANPEDPNvmilSCNPNYRKGLL 174
Cdd:cd15453   87 TKTNRIYRIFEQGKRSVTPPPF-ISPTSQLVITFSLTSLQVVGVIAWLGAQP--PHSVIDYEEQR----TVDPEQARGVL 159
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257 175 VNTSLDL-LLSVAGFS---------FAYMGKELPTNYNEAKFITFCMtfYFTSFITLCTV 224
Cdd:cd15453  160 KCDMSDLsLIGCLGYSlllmvtctvYAIKARGVPETFNEAKPIGFTM--YTTCIIWLAFV 217
7tmC_mGluR4 cd15452
metabotropic glutamate receptor 4 in group 3, member of the class C family of ...
15-221 9.37e-11

metabotropic glutamate receptor 4 in group 3, member of the class C family of seven-transmembrane G protein-coupled receptors; The receptors in group 3 include mGluRs 4, 6, 7, and 8. They are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group 1 mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to G(i/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320568 [Multi-domain]  Cd Length: 327  Bit Score: 60.76  E-value: 9.37e-11
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  15 VLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICISCIT 94
Cdd:cd15452    7 LLLAVLGIIATLFVVVTFVRYNDTPIVKASGRELSYVLLTGIFLCYATTFLMIAEPDLGTCSLRRIFLGLGMSISYAALL 86
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  95 VRSFQIVCVFKVARRFPRAygywVRYHGP---YVFVAAITAFKVAIVTVNQLVTPTGPTarANPEDPNVMilscNPNYRK 171
Cdd:cd15452   87 TKTNRIYRIFEQGKRSVSA----PRFISPasqLVITFSLISLQLLGVCVWFLVDPSHSV--VDYEDQRTP----DPQFAR 156
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257 172 GLLVNTSLDL-LLSVAGFS---------FAYMGKELPTNYNEAKFITFCMtfYFTSFITL 221
Cdd:cd15452  157 GVLKCDISDLsLICLLGYSmllmvtctvYAIKTRGVPETFNEAKPIGFTM--YTTCIIWL 214
7tmC_mGluR1 cd15449
metabotropic glutamate receptor 1 in group 1, member of the class C family of ...
11-230 2.95e-09

metabotropic glutamate receptor 1 in group 1, member of the class C family of seven-transmembrane G protein-coupled receptors; Group 1 mGluRs includes mGluR1 and mGluR5, as well as their closely related invertebrate receptors. They are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group 1 mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to G(i/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320565  Cd Length: 250  Bit Score: 55.79  E-value: 2.95e-09
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  11 TIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICI 90
Cdd:cd15449    3 SIIAVAFSCLGILVTMFVTLIFVLYRDTPVVKSSSRELCYIILAGIFLGYVCPFTLIAKPTTTSCYLQRLLVGLSSAMCY 82
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  91 SCITVRSFQIVCVF-----KVARRFPRAYGYWVRyhgpYVFVAAITAFKVAIVTVNQLVTPTGPTaRANPEDPNVMILSC 165
Cdd:cd15449   83 SALVTKTNRIARILagskkKICTRKPRFMSAWAQ----VVIASILISVQLTLVVTLIIMEPPMPI-LSYPSIKEVYLICN 157
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 299735257 166 NPNYrkGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMtfyFTSFITLCTVMSVYDG 230
Cdd:cd15449  158 TSNL--GVVAPLGYNGLLIMSCTYYAFKTRNVPANFNEAKYIAFTM---YTTCIIWLAFVPIYFG 217
7tmC_mGluR7 cd15451
metabotropic glutamate receptor 7 in group 3, member of the class C family of ...
12-211 3.41e-09

metabotropic glutamate receptor 7 in group 3, member of the class C family of seven-transmembrane G protein-coupled receptors; The receptors in group 3 include mGluRs 4, 6, 7, and 8. They are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group 1 mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to G(i/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320567  Cd Length: 307  Bit Score: 55.80  E-value: 3.41e-09
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  12 IFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICIS 91
Cdd:cd15451    4 VIPVFLAMLGIIATIFVMATFIRYNDTPIVRASGRELSYVLLTGIFLCYIITFLMIAKPDVAVCSFRRIFLGLGMCISYA 83
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  92 CITVRSFQIVCVFKVARRFPRAygywVRYHGPyvfvaaitAFKVAIVTVNQLVTPTGPTARANPEDPNVMI-----LSCN 166
Cdd:cd15451   84 ALLTKTNRIYRIFEQGKKSVTA----PRLISP--------TSQLAITSSLISVQLLGVLIWFAVDPPNIIIdydeqKTMN 151
                        170       180       190       200       210
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 299735257 167 PNYRKGLLVNTSLDL----------LLSVAGFSFAYMGKELPTNYNEAKFITFCM 211
Cdd:cd15451  152 PEQARGVLKCDITDLqiicslgysiLLMVTCTVYAIKTRGVPENFNEAKPIGFTM 206
7tmC_mGluR8 cd15454
metabotropic glutamate receptor 8 in group 3, member of the class C family of ...
15-221 4.39e-07

metabotropic glutamate receptor 8 in group 3, member of the class C family of seven-transmembrane G protein-coupled receptors; The receptors in group 3 include mGluRs 4, 6, 7, and 8. They are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group 1 mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to G(i/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320570 [Multi-domain]  Cd Length: 311  Bit Score: 49.63  E-value: 4.39e-07
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  15 VLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICISCIT 94
Cdd:cd15454    7 VFVAILGIIATTFVIVTFVRYNDTPIVRASGRELSYVLLTGIFLCYAITFLMIATPDTGICSFRRVFLGLGMCFSYAALL 86
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  95 VRSFQIVCVFKVARRFPRAygywVRYHGP---------YVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPNvMILSC 165
Cdd:cd15454   87 TKTNRIHRIFEQGKKSVTA----PKFISPasqlvitfsLISVQLLGVFVWFAVDPPHTIVDYGEQRTLDPEKAR-GVLKC 161
                        170       180       190       200       210
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 299735257 166 NPNyRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMtfYFTSFITL 221
Cdd:cd15454  162 DIS-DLSLICSLGYSILLMVTCTVYAIKTRGVPETFNEAKPIGFTM--YTTCIIWL 214
7tmC_mGluR5 cd15450
metabotropic glutamate receptor 5 in group 1, member of the class C family of ...
12-230 1.10e-05

metabotropic glutamate receptor 5 in group 1, member of the class C family of seven-transmembrane G protein-coupled receptors; Group 1 mGluRs includes mGluR1 and mGluR5, as well as their closely related invertebrate receptors. They are homodimeric class C G-protein coupled receptors which are activated by glutamate, the major excitatory neurotransmitter of the CNS. mGluRs are involved in regulating neuronal excitability and synaptic transmission via intracellular activation of second messenger signaling pathways. While the ionotropic glutamate receptor subtypes (AMPA, NMDA, and kainite) mediate fast excitatory postsynaptic transmission, mGluRs are known to mediate slower excitatory postsynaptic responses and to be involved in synaptic plasticity in the mammalian brain. In addition to seven-transmembrane helices, the class C GPCRs are characterized by a large N-terminal extracellular Venus flytrap-like domain, which is composed of two adjacent lobes separated by a cleft which binds an endogenous ligand. Moreover, they exist as either homo- or heterodimers, which are essential for their function. For instance, mGluRs form homodimers via interactions between the N-terminal Venus flytrap domains and the intermolecular disulphide bonds between cysteine residues located in the cysteine-rich domain (CRD). At least eight different subtypes of metabotropic receptors (mGluR1-8) have been identified and further classified into three groups based on their sequence homology, pharmacological properties, and signaling pathways. Group 1 (mGluR1 and mGluR5) receptors are predominantly located postsynaptically on neurons and are involved in long-term synaptic plasticity in the brain, including long-term potentiation (LTP) in the hippocampus and long-term depression (LTD) in the cerebellum. They are coupled to G(q/11) proteins, thereby activating phospholipase C to generate inositol-1,4,5-triphosphate (IP3) and diacyglycerol (DAG), which in turn lead to Ca2+ release and protein kinase C activation, respectively. Group 1 mGluR expression is shown to be strongly upregulated in animal models of epilepsy, brain injury, inflammatory, and neuropathic pain, as well as in patients with amyotrophic lateral sclerosis or multiple sclerosis. Group 2 (mGluR2 and mGluR3) and 3 (mGluR4, mGluR6, mGluR7, and mGluR8) receptors are predominantly localized presynaptically in the active region of neurotransmitter release. They are coupled to G(i/o) proteins, which leads to inhibition of adenylate cyclase activity and cAMP formation, and consequently to a decrease in protein kinase A (PKA) activity. Ultimately, activation of these receptors leads to inhibition of neurotransmitter release such as glutamate and GABA via inhibition of Ca2+ channels and activation of K+ channels. Furthermore, while activation of Group 1 mGluRs increases NMDA (N-methyl-D-aspartate) receptor activity and risk of neurotoxicity, Group 2 and 3 mGluRs decrease NMDA receptor activity and prevent neurotoxicity.


Pssm-ID: 320566  Cd Length: 250  Bit Score: 45.36  E-value: 1.10e-05
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  12 IFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYVGLPTISTCLCRQAFFNLCFTICIS 91
Cdd:cd15450    4 IAAVVFACLGLLATLFVTVIFIIYRDTPVVKSSSRELCYIILAGICLGYLCTFCLIAKPKQIYCYLQRIGIGLSPAMSYS 83
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257  92 CITVRSFQIVCVF-----KVARRFPRaygyWVRYHGPYVFVAAITAFKVAIVTVNQLVTPtgPTARANPEDPNVMILSCN 166
Cdd:cd15450   84 ALVTKTNRIARILagskkKICTKKPR----FMSACAQLVIAFILICIQLGIIVALFIMEP--PDIMHDYPSIREVYLICN 157
                        170       180       190       200       210       220
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 299735257 167 PNyRKGLLVNTSLDLLLSVAGFSFAYMGKELPTNYNEAKFITFCMtfyFTSFITLCTVMSVYDG 230
Cdd:cd15450  158 TT-NLGVVTPLGYNGLLILSCTFYAFKTRNVPANFNEAKYIAFTM---YTTCIIWLAFVPIYFG 217
7tmC_GABA-B-like cd15047
gamma-aminobutyric acid type B receptor and related proteins, member of the class C family of ...
9-159 1.79e-04

gamma-aminobutyric acid type B receptor and related proteins, member of the class C family of seven-transmembrane G protein-coupled receptors; The type B receptor for gamma-aminobutyric acid, GABA-B, is activated by its endogenous ligand GABA, the principal inhibitory neurotransmitter. The functional GABA-B receptor is an obligatory heterodimer composed of two related subunits, GABA-B1, which is primarily involved in GABA ligand binding, and GABA-B2, which is responsible for both G-protein coupling and trafficking of the heterodimer to the plasma membrane. Activation of GABA-B couples to G(i/o)-type G proteins, which in turn modulate three major downstream effectors: adenylate cyclase, voltage-sensitive Ca2+ channels, and inwardly-rectifying K+ channels. Consequently, GABA-B receptor produces slow and sustained inhibitory responses by decreased neurotransmitter release via inhibition of Ca2+ channels and by postsynaptic hyperpolarization via the activation of K+ channels through the G-protein beta-gamma dimer. The GABA-B is expressed in both pre- and postsynaptic sites of glutamatergic and GABAergic neurons in the brain where it regulates synaptic activity. Thus, the GABA-B receptor agonist, baclofen, is used to treat muscle tightness and cramping caused by spasticity in multiple sclerosis patients. Moreover, GABA-B antagonists improves cognitive performance in mammals, while GABA-B agonists suppress cognitive behavior. In most of the class C family members, the extracellular Venus-flytrap domain in the N-terminus is connected to the seven-transmembrane (7TM) via a cysteine-rich domain (CRD). However, in the GABA-B receptor, the CRD is absent in both subunits and the Venus-flytrap ligand-binding domain is directly connected to the 7TM via a 10-15 amino acids linker, suggesting that GABA-B receptor may utilize a different activation mechanism. Also included in this group are orphan receptors, GPR156 and GPR158, which are closely related to the GABA-B receptor family.


Pssm-ID: 320175  Cd Length: 263  Bit Score: 41.78  E-value: 1.79e-04
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 299735257   9 ALTIFVVLLAALGFLSTLAILAIFWRHLQTPMVRSAGGPMCFLILTALLVAYLMVPAYV---GLPTISTCLCRQAFFNLC 85
Cdd:cd15047    1 PLFIVFTVLSGIGILLALVFLIFNIKFRKNRVIKMSSPLFNNLILLGCILCYISVILFGlddSKPSSFLCTARPWLLSIG 80
                         90       100       110       120       130       140       150
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 299735257  86 FTICISCITVRSFQIVCVFKVARRFPRAygywVRYHGPYVFVAAITAFKVAIVTVNQLVTPTGPTARANPEDPN 159
Cdd:cd15047   81 FTLVFGALFAKTWRIYRIFTNKKLKRIV----IKDKQLLKIVGILLLIDIIILILWTIVDPLKPTRVLVLSEIS 150
 
Blast search parameters
Data Source: Precalculated data, version = cdd.v.3.21
Preset Options:Database: CDSEARCH/cdd   Low complexity filter: no  Composition Based Adjustment: yes   E-value threshold: 0.01

References:

  • Wang J et al. (2023), "The conserved domain database in 2023", Nucleic Acids Res.51(D)384-8.
  • Lu S et al. (2020), "The conserved domain database in 2020", Nucleic Acids Res.48(D)265-8.
  • Marchler-Bauer A et al. (2017), "CDD/SPARCLE: functional classification of proteins via subfamily domain architectures.", Nucleic Acids Res.45(D)200-3.
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