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.

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gi 1039732329  69 ITIMALYSIVCVVGLFGNFLVMYVIVSF 96
Cdd:cd14970     1 IVIPAVYSVVCVVGLTGNSLVIYVILRY 28

opioid receptors and related proteins, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes opioid receptors, somatostatin receptors, melanin-concentrating hormone receptors (MCHRs), and neuropeptides B/W receptors. Together they constitute the opioid receptor-like family, members of the class A G-protein coupled receptors. Opioid receptors are coupled to inhibitory G proteins of the G(i/o) family and are involved in regulating a variety of physiological functions such as pain, addiction, mood, stress, epileptic seizure, and obesity, among many others. G protein-coupled somatostatin receptors (SSTRs), which display strong sequence similarity with opioid receptors, binds somatostatin (somatotropin release inhibiting factor), a polypeptide hormone that regulates a wide variety of physiological functions such as neurotransmission, cell proliferation, contractility of smooth muscle cells, and endocrine signaling as well as inhibition of the release of many secondary hormones. MCHR binds melanin concentrating hormone and is presumably involved in the neuronal regulation of food intake. Despite strong homology with somatostatin receptors, MCHR does not appear to bind somatostatin. Neuropeptides B/W receptors are primarily expressed in the CNS and stimulate the cortisol secretion by activating the adenylate cyclase- and the phospholipase C-dependent signaling pathways.

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gi 1039732329  69 ITIMALYSIVCVVGLFGNFLVMYVIVSF 96
Cdd:cd14970     1 IVIPAVYSVVCVVGLTGNSLVIYVILRY 28

opioid receptors and related proteins, member of the class A family of seven-transmembrane G protein-coupled receptors; This group includes opioid receptors, somatostatin receptors, melanin-concentrating hormone receptors (MCHRs), and neuropeptides B/W receptors. Together they constitute the opioid receptor-like family, members of the class A G-protein coupled receptors. Opioid receptors are coupled to inhibitory G proteins of the G(i/o) family and are involved in regulating a variety of physiological functions such as pain, addiction, mood, stress, epileptic seizure, and obesity, among many others. G protein-coupled somatostatin receptors (SSTRs), which display strong sequence similarity with opioid receptors, binds somatostatin (somatotropin release inhibiting factor), a polypeptide hormone that regulates a wide variety of physiological functions such as neurotransmission, cell proliferation, contractility of smooth muscle cells, and endocrine signaling as well as inhibition of the release of many secondary hormones. MCHR binds melanin concentrating hormone and is presumably involved in the neuronal regulation of food intake. Despite strong homology with somatostatin receptors, MCHR does not appear to bind somatostatin. Neuropeptides B/W receptors are primarily expressed in the CNS and stimulate the cortisol secretion by activating the adenylate cyclase- and the phospholipase C-dependent signaling pathways.

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gi 1039732329  69 ITIMALYSIVCVVGLFGNFLVMYVIVSF 96
Cdd:cd14970     1 IVIPAVYSVVCVVGLTGNSLVIYVILRY 28

nociceptin/orphanin FQ peptide receptor, member of the class A family of seven-transmembrane G protein-coupled receptors; The nociceptin (NOP) receptor binds nociceptin or orphanin FQ, a 17 amino acid endogenous neuropeptide. The NOP receptor is involved in the modulation of various brain activities including instinctive and emotional behaviors. The opioid receptor family is composed of four major subtypes: mu (MOP), delta (DOP), kappa (KOP) opioid receptors, and the nociceptin/orphanin FQ peptide receptor (NOP). They are distributed widely in the central nervous system and respond to classic alkaloid opiates, such as morphine and heroin, as well as to endogenous peptide ligands, which include dynorphins, enkephalins, endorphins, endomorphins, and nociceptin. Opioid receptors are coupled to inhibitory G proteins of the G(i/o) family and involved in regulating a variety of physiological functions such as pain, addiction, mood, stress, epileptic seizure, and obesity, among many others.

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gi 1039732329  69 ITIMALYSIVCVVGLFGNFLVMYVIVSF 96
Cdd:cd15092     1 VTIVVVYLIVCVVGLVGNCLVMYVILRH 28

opioid receptor subtype kappa, member of the class A family of seven-transmembrane G protein-coupled receptors; The kappa-opioid receptor binds the opioid peptide dynorphin as the primary endogenous ligand. The opioid receptor family is composed of four major subtypes: mu (MOP), delta (DOP), kappa (KOP) opioid receptors, and the nociceptin/orphanin FQ peptide receptor (NOP). They are distributed widely in the central nervous system and respond to classic alkaloid opiates, such as morphine and heroin, as well as to endogenous peptide ligands, which include dynorphins, enkephalins, endorphins, endomorphins, and nociceptin. Opioid receptors are coupled to inhibitory G proteins of the G(i/o) family and involved in regulating a variety of physiological functions such as pain, addiction, mood, stress, epileptic seizure, and obesity, among many others.

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gi 1039732329  69 ITIMALYSIVCVVGLFGNFLVMYVIVSF 96
Cdd:cd15091     1 VIITAVYSVVFVVGLVGNSLVMFVIIRY 28

classical and atypical chemokine receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; Chemokines are principal regulators for leukocyte trafficking, recruitment, and activation. Chemokine family membership is defined on the basis of sequence homology and on the presence of variations on a conserved cysteine motif, which allows the family to further divide into four subfamilies (CC, CXC, XC, and CX3C). Chemokines interact with seven-transmembrane receptors which are typically coupled to G protein for signaling. Currently, there are ten known receptors for CC chemokines, seven for CXC chemokines, and single receptors for the XC and CX3C chemokines. In addition to these classical chemokine receptors, there exists a subfamily of atypical chemokine receptors (ACKRs) that are unable to couple to G-proteins and, instead, they preferentially mediate beta-arrestin dependent processes, such as receptor internalization, after ligand binding. The classical chemokine receptors contain a conserved DRYLAIV motif in the second intracellular loop, which is required for G-protein coupling. However, the ACKRs lack this conserved motif and fail to couple to G-proteins and induce classical GPCR signaling. Five receptors have been identified for the ACKR family, including CC-chemokine receptors like 1 and 2 (CCRL1 and CCRL2), CXCR7, Duffy antigen receptor for chemokine (DARC), and D6. Both ACKR1 (DARC) and ACKR3 (CXCR7) show low sequence homology to the classic chemokine receptors.

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gi 1039732329  73 ALYSIVCVVGLFGNFLVMYVIVSF 96
Cdd:cd14984     5 VLYSLVFLLGLVGNSLVLLVLLYY 28

neuropeptide Y receptors and related proteins, member of the class A family of seven-transmembrane G protein-coupled receptors; NPY is a 36-amino acid peptide neurotransmitter with a C-terminal tyrosine amide residue that is widely distributed in the brain and the autonomic nervous system of many mammalian species. NPY exerts its functions through five, G-protein coupled receptor subtypes including NPY1R, NPY2R, NPY4R, NPY5R, and NPY6R; however, NPY6R is not functional in humans. NYP receptors are also activated by its two other family members, peptide YY (PYY) and pancreatic polypeptide (PP). They typically couple to Gi or Go proteins, which leads to a decrease in adenylate cyclase activity, thereby decreasing intracellular cAMP levels, and are involved in diverse physiological roles including appetite regulation, circadian rhythm, and anxiety. Also included in this subgroup is prolactin-releasing peptide (PrRP) receptor (previously known as GPR10), which is activated by its endogenous ligand PrRP, a neuropeptide possessing C-terminal Arg-Phe-amide motif. There are two active isoforms of PrRP in mammals: one consists of 20 amino acid residues (PrRP-20) and the other consists of 31 amino acid residues (PrRP-31). PrRP receptor shows significant sequence homology to the NPY receptors, and a micromolar level of NPY can bind and completely inhibit the PrRP-evoked intracellular calcium response in PrRP receptor-expressing cells, suggesting that the PrRP receptor shares a common ancestor with the NPY receptors.

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gi 1039732329  69 ITIMALYSIVCVVGLFGNFLVMYVIVSF 96
Cdd:cd15203     1 IILILLYGLIIVLGVVGNLLVIYVVLRN 28

somatostatin receptor type 1, member of the class A family of seven-transmembrane G protein-coupled receptors; G protein-coupled somatostatin receptors (SSTRs) are composed of five distinct subtypes (SSTR1-5) that display strong sequence similarity with opioid receptors. All five receptor subtypes bind the natural somatostatin (somatotropin release inhibiting factor), a polypeptide hormone that regulates a wide variety of physiological functions such as neurotransmission, cell proliferation, contractility of smooth muscle cells, and endocrine signaling as well as inhibition of the release of many secondary hormones. SSTR1 is coupled to a Na/H exchanger, voltage-dependent calcium channels, and AMPA/kainate glutamate channels. SSTR1 is expressed in the normal human pituitary and in nearly half of all pituitary adenoma subtypes.

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gi 1039732329  69 ITIMALYSIVCVVGLFGNFLVMYVIVSF 96
Cdd:cd15970     1 ILISFIYSVVCLVGLCGNSMVIYVILRY 28

ecdysis-triggering hormone receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; This subgroup represents the ecdysis-triggering hormone receptors found in insects, which are members of the class A family of seven-transmembrane G-protein coupled receptors. Ecdysis-triggering hormones are vital regulatory signals that govern the stereotypic physiological sequence leading to cuticle shedding in insects. Thus, the ETH signaling system has been a target for the design of more sophisticated insect-selective pest control strategies. Two subtypes of ecdysis-triggering hormone receptor were identified in Drosophila melanogaster. Blood-borne ecdysis-triggering hormone (ETH) activates the behavioral sequence through direct actions on the central nervous system. In insects, ecdysis is thought to be controlled by the interaction between peptide hormones; in particular between ecdysis-triggering hormone (ETH) from the periphery and eclosion hormone (EH) and crustacean cardioactive peptide (CCAP) from the central nervous system. All GPCRs have 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.

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gi 1039732329  69 ITIMALYSIVCVVGLFGNFLVMYVIV 94
Cdd:cd14997     1 VLVSVVYGVIFVVGVLGNVLVGIVVW 26

relaxin-3 like peptide receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; This G protein-coupled receptor subfamily is composed of the relaxin-3 like peptide receptors, RNL3R1 and RNL3R2, and similar proteins. The relaxin-3 like peptide family includes relaxin-1, -2, -3, as well as insulin-like (INSL) peptides 3 to 6. RNL3/relaxin-3 and INSL5 are the endogenous ligands for RNL3R1 and RNL3R2, respectively. RNL3R1, also called GPCR135 or RXFP3, is predominantly expressed in the brain and is implicated in stress, anxiety, feeding, and metabolism. Insulin-like peptide 5 (INSL5), the endogenous ligand for RNL3R2 (also called GPCR142 or RXFP4), plays a role in fat and glucose metabolism. INSL5 is highly expressed in human rectal and colon tissues. Both RNL3R1 and RNL3R2 signal through G(i) protein and inhibit adenylate cyclase, thereby inhibit cAMP accumulation. RNL3R1 is shown to activate Erk1/2 signaling pathway.

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gi 1039732329  69 ITIMALYSIVCVVGLFGNFLVMYVIVS 95
Cdd:cd14976     1 NLVSVVYMVVFTVGLLGNLLVLYLLKS 27

somatostatin receptors, member of the class A family of seven-transmembrane G protein-coupled receptors; G protein-coupled somatostatin receptors (SSTRs) are composed of five distinct subtypes (SSTR1-5) that display strong sequence similarity with opioid receptors. All five receptor subtypes bind the natural somatostatin (somatotropin release inhibiting factor), a polypeptide hormone that regulates a wide variety of physiological functions such as neurotransmission, cell proliferation, contractility of smooth muscle cells, and endocrine signaling as well as inhibition of the release of many secondary hormones. They share common signaling cascades such as inhibition of adenylyl cyclase, activation of phosphotyrosine phosphatase activity, and G-protein-dependent regulation of MAPKs.

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gi 1039732329  69 ITIMALYSIVCVVGLFGNFLVMYVIVSF 96
Cdd:cd15093     1 VLIPCIYAVVCLVGLCGNSLVIYVVLRY 28