C2 domain second repeat present in Synaptotagmins 14 and 16; Synaptotagmin 14 and 16 are membrane-trafficking proteins in specific tissues outside the brain. Both of these contain C-terminal tandem C2 repeats, but only Synaptotagmin 14 has an N-terminal transmembrane domain and a putative fatty-acylation site. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium and this is indeed the case here. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  64 APELLVGLSYNATTGRLSVEMIKGSHFRNLAVNRAPDTYGKLFLLNSVGQEMSRCKTSIRRGQPNPVYKETFVFQVALFQ 143
Cdd:cd08408   1 VPELLLGLEYNALTGRLSVEVIKGSNFKNLAMNKAPDTYVKLTLLNSDGQEISKSKTSIRRGQPDPEFKETFVFQVALFQ 80

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 26454852 144 LSDVTLMISVYNRRTMKRKEMIGWIALGQNSSGEEEQDHWEEMKETKGQQICRWHTLL 201
Cdd:cd08408  81 LSEVTLMFSVYNKRKMKRKEMIGWFSLGLNSSGEEEEEHWNEMKESKGQQVCRWHTLL 138

C2 domain second repeat present in Synaptotagmins 14 and 16; Synaptotagmin 14 and 16 are membrane-trafficking proteins in specific tissues outside the brain. Both of these contain C-terminal tandem C2 repeats, but only Synaptotagmin 14 has an N-terminal transmembrane domain and a putative fatty-acylation site. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium and this is indeed the case here. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  64 APELLVGLSYNATTGRLSVEMIKGSHFRNLAVNRAPDTYGKLFLLNSVGQEMSRCKTSIRRGQPNPVYKETFVFQVALFQ 143
Cdd:cd08408   1 VPELLLGLEYNALTGRLSVEVIKGSNFKNLAMNKAPDTYVKLTLLNSDGQEISKSKTSIRRGQPDPEFKETFVFQVALFQ 80

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 26454852 144 LSDVTLMISVYNRRTMKRKEMIGWIALGQNSSGEEEQDHWEEMKETKGQQICRWHTLL 201
Cdd:cd08408  81 LSEVTLMFSVYNKRKMKRKEMIGWFSLGLNSSGEEEEEHWNEMKESKGQQVCRWHTLL 138

Protein kinase C conserved region 2 (CalB); Ca2+-binding motif present in phospholipases, protein kinases C, and synaptotagmins (among others). Some do not appear to contain Ca2+-binding sites. Particular C2s appear to bind phospholipids, inositol polyphosphates, and intracellular proteins. Unusual occurrence in perforin. Synaptotagmin and PLC C2s are permuted in sequence with respect to N- and C-terminal beta strands. SMART detects C2 domains using one or both of two profiles.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852     79 RLSVEMIKGSHFRNLAVNRAPDTYGKLFLLnsvGQEMSRCKTSIRRGQPNPVYKETFVFQVALFQLSDvtLMISVYNRRT 158
Cdd:smart00239   1 TLTVKIISARNLPPKDKGGKSDPYVKVSLD---GDPKEKKKTKVVKNTLNPVWNETFEFEVPPPELAE--LEIEVYDKDR 75

                           90
                   ....*....|..
gi 26454852    159 MKRKEMIGWIAL 170
Cdd:smart00239  76 FGRDDFIGQVTI 87

C2 domain second repeat present in Synaptotagmins 14 and 16; Synaptotagmin 14 and 16 are membrane-trafficking proteins in specific tissues outside the brain. Both of these contain C-terminal tandem C2 repeats, but only Synaptotagmin 14 has an N-terminal transmembrane domain and a putative fatty-acylation site. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium and this is indeed the case here. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  64 APELLVGLSYNATTGRLSVEMIKGSHFRNLAVNRAPDTYGKLFLLNSVGQEMSRCKTSIRRGQPNPVYKETFVFQVALFQ 143
Cdd:cd08408   1 VPELLLGLEYNALTGRLSVEVIKGSNFKNLAMNKAPDTYVKLTLLNSDGQEISKSKTSIRRGQPDPEFKETFVFQVALFQ 80

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 26454852 144 LSDVTLMISVYNRRTMKRKEMIGWIALGQNSSGEEEQDHWEEMKETKGQQICRWHTLL 201
Cdd:cd08408  81 LSEVTLMFSVYNKRKMKRKEMIGWFSLGLNSSGEEEEEHWNEMKESKGQQVCRWHTLL 138

C2 domain second repeat present in Synaptotagmin 7; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. Synaptotagmin 7, a member of class 2 synaptotagmins, is located in presynaptic plasma membranes in neurons, dense-core vesicles in endocrine cells, and lysosomes in fibroblasts. It has been shown to play a role in regulation of Ca2+-dependent lysosomal exocytosis in fibroblasts and may also function as a vesicular Ca2+-sensor. It is distinguished from the other synaptotagmins by having over 12 splice forms. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  66 ELLVGLSYNATTGRLSVEMIKGSHFRNLAVNRAPDTYGKLFLLNSvGQEMSRCKTSIRRGQPNPVYKETFVFQVALFQLS 145
Cdd:cd08405   3 ELLLSLCYNPTANRITVNIIKARNLKAMDINGTSDPYVKVWLMYK-DKRVEKKKTVIKKRTLNPVFNESFIFNIPLERLR 81

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*
gi 26454852 146 DVTLMISVYNRRTMKRKEMIGWIALGQNSSGEEEQdHWEEMKETKGQQICRWHTL 200
Cdd:cd08405  82 ETTLIITVMDKDRLSRNDLIGKIYLGWKSGGLELK-HWKDMLSKPRQPVAQWHRL 135

C2 domain second repeat present in Synaptotagmin 17; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. Synaptotagmin 17 is located in the brain, kidney, and prostate and is thought to be a peripheral membrane protein. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  66 ELLVGLSYNATTGRLSVEMIKGSHFRNLAVNRAPDTYGKLFLLNsvGQEMSRCK-TSIRRGQPNPVYKETFVFQVALFQL 144
Cdd:cd08410   2 ELLLSLNYLPSAGRLNVDIIRAKQLLQTDMSQGSDPFVKIQLVH--GLKLIKTKkTSCMRGTIDPFYNESFSFKVPQEEL 79

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 26454852 145 SDVTLMISVYNRRTMKRKEMIGWIALGQNSSGEEEQDHWEEMKETKGQQICRWHTL 200
Cdd:cd08410  80 ENVSLVFTVYGHNVKSSNDFIGRIVIGQYSSGPSETNHWRRMLNSQRTAVEQWHSL 135

C2 domain second repeat present in Synaptotagmin 1; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. Synaptotagmin 1, a member of the class 1 synaptotagmins, is located in the brain and endocranium and localized to the synaptic vesicles and secretory granules. It functions as a Ca2+ sensor for fast exocytosis. It, like synaptotagmin-2, has an N-glycosylated N-terminus. Synaptotagmin 4, a member of class 4 synaptotagmins, is located in the brain. It functions are unknown. It, like synaptotagmin-11, has an Asp to Ser substitution in its C2A domain. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  71 LSYNATTGRLSVEMIKGSHFRNLAVNRAPDTYGKLFLLNSvGQEMSRCKTSIRRGQPNPVYKETFVFQVALFQLSDVTLM 150
Cdd:cd08402   8 LRYVPTAGKLTVVILEAKNLKKMDVGGLSDPYVKIHLMQN-GKRLKKKKTTIKKRTLNPYYNESFSFEVPFEQIQKVHLI 86

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|
gi 26454852 151 ISVYNRRTMKRKEMIGWIALGQNSSGEEEQdHWEEMKETKGQQICRWHTL 200
Cdd:cd08402  87 VTVLDYDRIGKNDPIGKVVLGCNATGAELR-HWSDMLASPRRPIAQWHTL 135

C2 domain second repeat present in Synaptotagmin 12; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. Synaptotagmin 12, a member of class 6 synaptotagmins, is located in the brain. It functions are unknown. It, like synaptotagmins 8 and 13, do not have any consensus Ca2+ binding sites. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  66 ELLVGLSYNATTGRLSVEMIKGshfRNLAVNRAPDT---YGKLFLLNSvGQEMSRCKTSIRRGQPNPVYKETFVFQVALF 142
Cdd:cd08406   3 EILLSLSYLPTAERLTVVVVKA---RNLVWDNGKTTadpFVKVYLLQD-GRKISKKKTSVKRDDTNPIFNEAMIFSVPAI 78

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 26454852 143 QLSDVTLMISVYNRRTMKRKEMIGWIALGQNSSGEEEQdHWEEMKETKGQQICRWHTL 200
Cdd:cd08406  79 VLQDLSLRVTVAESTEDGKTPNVGHVIIGPAASGMGLS-HWNQMLASLRKPVAMWHPL 135

C2 domain second repeat present in Synaptotagmin 15; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. It is thought to be involved in the trafficking and exocytosis of secretory vesicles in non-neuronal tissues and is Ca2+ independent. Human synaptotagmin 15 has 2 alternatively spliced forms that encode proteins with different C-termini. The larger, SYT15a, contains a N-terminal TM region, a putative fatty-acylation site, and 2 tandem C terminal C2 domains. The smaller, SYT15b, lacks the C-terminal portion of the second C2 domain. Unlike most other synaptotagmins it is nearly absent in the brain and rather is found in the heart, lungs, skeletal muscle, and testis. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  66 ELLVGLSYNATTGRLSVEMIKGSHFRNLAVNRApDTYGKLFLLNSvGQEMSRCKTSIRRGQPNPVYKETFVFQVALFQLS 145
Cdd:cd08409   3 DIQISLTYNPTLNRLTVVVLRARGLRQLDHAHT-SVYVKVSLMIH-NKVVKTKKTEVVDGAASPSFNESFSFKVTSRQLD 80

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 26454852 146 DVTLMISVYNRRTMKRKEMIGWIALG--QNSSGEEEQdHWEEMKETKGQQICRWHTL 200
Cdd:cd08409  81 TASLSLSVMQSGGVRKSKLLGRVVLGpfMYARGKELE-HWNDMLSKPKELIKRWHAL 136

Protein kinase C conserved region 2 (CalB); Ca2+-binding motif present in phospholipases, protein kinases C, and synaptotagmins (among others). Some do not appear to contain Ca2+-binding sites. Particular C2s appear to bind phospholipids, inositol polyphosphates, and intracellular proteins. Unusual occurrence in perforin. Synaptotagmin and PLC C2s are permuted in sequence with respect to N- and C-terminal beta strands. SMART detects C2 domains using one or both of two profiles.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852     79 RLSVEMIKGSHFRNLAVNRAPDTYGKLFLLnsvGQEMSRCKTSIRRGQPNPVYKETFVFQVALFQLSDvtLMISVYNRRT 158
Cdd:smart00239   1 TLTVKIISARNLPPKDKGGKSDPYVKVSLD---GDPKEKKKTKVVKNTLNPVWNETFEFEVPPPELAE--LEIEVYDKDR 75

                           90
                   ....*....|..
gi 26454852    159 MKRKEMIGWIAL 170
Cdd:smart00239  76 FGRDDFIGQVTI 87

C2A domain first repeat present in Synaptotagmins 15 and 17; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. It is thought to be involved in the trafficking and exocytosis of secretory vesicles in non-neuronal tissues and is Ca2+ independent. Human synaptotagmin 15 has 2 alternatively spliced forms that encode proteins with different C-termini. The larger, SYT15a, contains a N-terminal TM region, a putative fatty-acylation site, and 2 tandem C terminal C2 domains. The smaller, SYT15b, lacks the C-terminal portion of the second C2 domain. Unlike most other synaptotagmins it is nearly absent in the brain and rather is found in the heart, lungs, skeletal muscle, and testis. Synaptotagmin 17 is located in the brain, kidney, and prostate and is thought to be a peripheral membrane protein. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the first C2 repeat, C2A, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  73 YNATTGRLSVEMIKGshfRNL----AVNRAPDTYGKLFLLNSvgQEMSRcKTSIRRGQPNPVYKETFVFQVALFQLSDVT 148
Cdd:cd08390   9 YDLEEEQLTVSLIKA---RNLpprtKDVAHCDPFVKVCLLPD--ERRSL-QSKVKRKTQNPNFDETFVFQVSFKELQRRT 82

                        90       100
                ....*....|....*....|..
gi 26454852 149 LMISVYNRRTMKRKEMIGWIAL 170
Cdd:cd08390  83 LRLSVYDVDRFSRHCIIGHVLF 104

C2A domain first repeat present in Synaptotagmins 1, 5, 6, 9, and 10; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. Synaptotagmin 1, a member of class 1 synaptotagmins, is located in the brain and endocranium and localized to the synaptic vesicles and secretory granules. It functions as a Ca2+ sensor for fast exocytosis as do synaptotagmins 5, 6, and 10. It is distinguished from the other synaptotagmins by having an N-glycosylated N-terminus. Synaptotagmins 5, 6, and 10, members of class 3 synaptotagmins, are located primarily in the brain and localized to the active zone and plasma membrane. They is distinguished from the other synaptotagmins by having disulfide bonds at its N-terminus. Synaptotagmin 6 also regulates the acrosome reaction, a unique Ca2+-regulated exocytosis, in sperm. Synaptotagmin 9, a class 5 synaptotagmins, is located in the brain and localized to the synaptic vesicles. It is thought to be a Ca2+-sensor for dense-core vesicle exocytosis. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the first C2 repeat, C2A, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  71 LSYNATTGRLSVEMIKGSHFRNLAVNRAPDTYGKLFLLNSvgqemsRCK---TSIRRGQPNPVYKETFVFQVALFQLSDV 147
Cdd:cd08385   9 LDYDFQSNQLTVGIIQAADLPAMDMGGTSDPYVKVYLLPD------KKKkfeTKVHRKTLNPVFNETFTFKVPYSELGNK 82

                        90
                ....*....|....*....
gi 26454852 148 TLMISVYNRRTMKRKEMIG 166
Cdd:cd08385  83 TLVFSVYDFDRFSKHDLIG 101

C2 domain second repeat present in Synaptotagmin 13; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. Synaptotagmin 13, a member of class 6 synaptotagmins, is located in the brain. It functions are unknown. It, like synaptotagmins 8 and 12, does not have any consensus Ca2+ binding sites. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  66 ELLVGLSYNATTGRLSVEMIKGshfRNLAVNRAPDTYGK----LFLLNSVGQEMSRCKTSIRRGQPNPVYKETFVFQVA- 140
Cdd:cd08407   3 EVLLSISYLPAANRLLVVVIKA---KNLHSDQLKLLLGIdvsvKVTLKHQNAKLKKKQTKRAKHKINPVWNEMIMFELPs 79

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 26454852 141 -LFQLSDVTLmiSVYNRRTMKRKEMIGWIALGQNSSGEEEQdHWEEMKETKGQQICRWHTL 200
Cdd:cd08407  80 eLLAASSVEL--EVLNQDSPGQSLPLGRCSLGLHTSGTERQ-HWEEMLDNPRRQIAMWHQL 137

C2 domain first repeat present in Synaptotagmin-like protein 3; All Slp members basically share an N-terminal Slp homology domain (SHD) and C-terminal tandem C2 domains (named the C2A domain and the C2B domain) with the SHD and C2 domains being separated by a linker sequence of various length. SHD of Slp (except for the Slp4-SHD) function as a specific Rab27A/B-binding domain. In addition to Slp, rabphilin, Noc2, and Munc13-4 also function as Rab27-binding proteins. Little is known about the expression or localization of Slp3. The C2A domain of Slp3 is Ca2+ dependent. It has been demonstrated that Slp3 promotes dense-core vesicle exocytosis. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the first C2 repeat, C2A, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  66 ELLVGLSYNATTGRLSVeMIKGShfRNLAV----NRAPDTYGKLFLLNSVGQEmSRCKTSIRRGQPNPVYKETFVFQVAL 141
Cdd:cd08392   3 EIEFALHYNFRTSCLEI-TIKAC--RNLAYgdekKKKCHPYVKVCLLPDKSHN-SKRKTAVKKGTVNPVFNETLKYVVEA 78

                        90       100
                ....*....|....*....|....*
gi 26454852 142 FQLSDVTLMISVYNRRTMKRKEMIG 166
Cdd:cd08392  79 DLLSSRQLQVSVWHSRTLKRRVFLG 103

C2 domain second repeat present in class II phosphatidylinositol 3-kinases (PI3Ks); There are 3 classes of PI3Ks based on structure, regulation, and specificity. All classes contain a N-terminal C2 domain, a PIK domain, and a kinase catalytic domain. Unlike class I and class III, class II PI3Ks have additionally a PX domain and a C-terminal C2 domain containing a nuclear localization signal both of which bind phospholipids though in a slightly different fashion. PI3Ks (AKA phosphatidylinositol (PtdIns) 3-kinases) regulate cell processes such as cell growth, differentiation, proliferation, and motility. PI3Ks work on phosphorylation of phosphatidylinositol, phosphatidylinositide (4)P (PtdIns (4)P),2 or PtdIns(4,5)P2. Specifically they phosphorylate the D3 hydroxyl group of phosphoinositol lipids on the inositol ring. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  71 LSYNATTgrLSVeMIKgsHFRNLAVNR--APDTYGKLFLLNSVgQEMSRCKTSIRRGQPNPVYKETFVFQ-VALFQLSDV 147
Cdd:cd08381   8 ISYKNGT--LFV-MVM--HAKNLPLLDgsDPDPYVKTYLLPDP-QKTTKRKTKVVRKTRNPTFNEMLVYDgLPVEDLQQR 81

                        90
                ....*....|....*....
gi 26454852 148 TLMISVYNRRTMKRKEMIG 166
Cdd:cd08381  82 VLQVSVWSHDSLVENEFLG 100

C2A domain first repeat present in Synaptotagmins 14 and 16; Synaptotagmin 14 and 16 are membrane-trafficking proteins in specific tissues outside the brain. Both of these contain C-terminal tandem C2 repeats, but only Synaptotagmin 14 has an N-terminal transmembrane domain and a putative fatty-acylation site. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium and this is indeed the case here. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the first C2 repeat, C2A, and has a type-I topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  66 ELLVGLSYNATTGRLSVEMIKGSHFRNLAVNRAPDTYGKLFLLNSVGQemsRCKTSIRRGqPNPVYKETFVF-QVALFQL 144
Cdd:cd08389   4 DLDVAFEYDPSARKLTVTVIRAQDIPTKDRGGASSWQVHLVLLPSKKQ---RAKTKVQRG-PNPVFNETFTFsRVEPEEL 79

                        90       100
                ....*....|....*....|..
gi 26454852 145 SDVTLMISVYNRRTMKRKEMIG 166
Cdd:cd08389  80 NNMALRFRLYGVERMRKERLIG 101

C2 domain second repeat in Ferlin; Ferlins are involved in vesicle fusion events. Ferlins and other proteins, such as Synaptotagmins, are implicated in facilitating the fusion process when cell membranes fuse together. There are six known human Ferlins: Dysferlin (Fer1L1), Otoferlin (Fer1L2), Myoferlin (Fer1L3), Fer1L4, Fer1L5, and Fer1L6. Defects in these genes can lead to a wide range of diseases including muscular dystrophy (dysferlin), deafness (otoferlin), and infertility (fer-1, fertilization factor-1). Structurally they have 6 tandem C2 domains, designated as (C2A-C2F) and a single C-terminal transmembrane domain, though there is a new study that disputes this and claims that there are actually 7 tandem C2 domains with another C2 domain inserted between C2D and C2E. In a subset of them (Dysferlin, Myoferlin, and Fer1) there is an additional conserved domain called DysF. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-II topology.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 26454852 119 KTSIRRGQPNPVYKETFVF--QVALFQLSDVTLMISVYNRRTMKRKEMIG 166
Cdd:cd04011  35 YTSVKKGTNCPFYNEYFFFnfHESPDELFDKIIKISVYDSRSLRSDTLIG 84

C2 domain first repeat found in Tac2-N (Tandem C2 protein in Nucleus); Tac2-N contains two C2 domains and a short C-terminus including a WHXL motif, which are key in stabilizing transport vesicles to the plasma membrane by binding to a plasma membrane. However unlike the usual carboxyl-terminal-type (C-type) tandem C2 proteins, it lacks a transmembrane domain, a Slp-homology domain, and a Munc13-1-interacting domain. Homology search analysis indicate that no known protein motifs are located in its N-terminus, making Tac2-N a novel class of Ca2+-independent, C-type tandem C2 proteins. The C2 domain was first identified in PKC. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852 117 RCKTSIRRGQPNPVYKETFVFQVALFQLSDVTLMISVYNRrtMKRKEMIGWIALGQNSSGEEEQDHWEEM 186
Cdd:cd08684  36 HFKSSAKEGSNDIEFMETFVFAIKLQNLQTVRLVFKIQTQ--TPRKRTIGECSLSLRTLSTQETDHWLEI 103

C2 domain second repeat found in Multiple C2 domain and Transmembrane region Proteins (MCTP); MCTPs are involved in Ca2+ signaling at the membrane. MCTP is composed of a variable N-terminal sequence, three C2 domains, two transmembrane regions (TMRs), and a short C-terminal sequence. It is one of four protein classes that are anchored to membranes via a transmembrane region; the others being synaptotagmins, extended synaptotagmins, and ferlins. MCTPs are the only membrane-bound C2 domain proteins that contain two functional TMRs. MCTPs are unique in that they bind Ca2+ but not phospholipids. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-II topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  80 LSVEMIKGSHFRNLAVNRAPDTYGKLFLlnsvGQEmsRCKTSIRRGQPNPVYKETFVFQvaLFQLSDVTLMISVYNRRTM 159
Cdd:cd08376   2 VTIVLVEGKNLPPMDDNGLSDPYVKFRL----GNE--KYKSKVCSKTLNPQWLEQFDLH--LFDDQSQILEIEVWDKDTG 73

                ....*..
gi 26454852 160 KRKEMIG 166
Cdd:cd08376  74 KKDEFIG 80

C2 domain first repeat contained in Rab3-interacting molecule (RIM) proteins; RIMs are believed to organize specialized sites of the plasma membrane called active zones. They also play a role in controlling neurotransmitter release, plasticity processes, as well as memory and learning. RIM contains an N-terminal zinc finger domain, a PDZ domain, and two C-terminal C2 domains (C2A, C2B). C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. Members here have a type-I topology and do not bind Ca2+.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 26454852  66 ELLVGLSYNATTGRLSVEMIKGshfRNLAV---NRAPDTYGKLFLLNSVGQEMSRcKTSIRRGQPNPVYKETFVFQ-VAL 141
Cdd:cd04031   4 RIQIQLWYDKVTSQLIVTVLQA---RDLPPrddGSLRNPYVKVYLLPDRSEKSKR-RTKTVKKTLNPEWNQTFEYSnVRR 79

                        90
                ....*....|....
gi 26454852 142 FQLSDVTLMISVYN 155
Cdd:cd04031  80 ETLKERTLEVTVWD 93

C2 domain present in Soybean genes Regulated by Cold 2 (SRC2)-like proteins; SRC2 production is a response to pathogen infiltration. The initial response of increased Ca2+ concentrations are coupled to downstream signal transduction pathways via calcium binding proteins. SRC2 contains a single C2 domain which localizes to the plasma membrane and is involved in Ca2+ dependent protein binding. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 26454852 116 SRCKTSI-RRGQPNPVYKETFVFQV--ALFQLSDVTLMISVYNRRTMKRKEMIGW 167
Cdd:cd04051  33 HKQSTPVdRDGGTNPTWNETLRFPLdeRLLQQGRLALTIEVYCERPSLGDKLIGE 87