C2 domain; 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 2028695507 603 KGNIQFAIEYVESLKELHVFVAQCKDLAAADVKKQRSDPYVKAYLLPDKGKMGKKKTLVVKKTLNPVYNEILR 675
Cdd:cd08393     1 QGSVQFALDYDPKLRELHVHVIQCQDLAAADPKKQRSDPYVKTYLLPDKSNRGKRKTSVKKKTLNPVFNETLR 73

C2 domain first repeat present in Synaptotagmin-like proteins 1 and 2; 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. Slp1/JFC1 and Slp2/exophilin 4 promote granule docking to the plasma membrane. Additionally, their C2A domains are both Ca2+ independent, unlike Slp3 and Slp4/granuphilin which are Ca2+ dependent. It is thought that SHD (except for the Slp4-SHD) functions as a specific Rab27A/B-binding domain. In addition to Slps, rabphilin, Noc2, and Munc13-4 also function as Rab27-binding proteins. 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2028695507 603 KGNIQFAIEYVESLKELHVFVAQCKDLAAADVKKQRSDPYVKAYLLPDKGKMGKKKTLVVKKTLNPVYNEILR 675
Cdd:cd08393     1 QGSVQFALDYDPKLRELHVHVIQCQDLAAADPKKQRSDPYVKTYLLPDKSNRGKRKTSVKKKTLNPVFNETLR 73

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 2028695507  711 VHIWVKECLDLPLL-RGSHLNSFVKCTILPDTSRKsrQKTRAVGKTTNPIFNHTMVYDGFRPEDlmeACVELTVWDHYKL 789
Cdd:smart00239   2 LTVKIISARNLPPKdKGGKSDPYVKVSLDGDPKEK--KKTKVVKNTLNPVWNETFEFEVPPPEL---AELEIEVYDKDRF 76

                           90
                   ....*....|...
gi 2028695507  790 T-NQFLGGLRIGF 801
Cdd:smart00239  77 GrDDFIGQVTIPL 89

C2 domain;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2028695507 619 LHVFVAQCKDLAAADvKKQRSDPYVKAYLLPDKGKmgkKKTLVVKKTLNPVYNEIL 674
Cdd:pfam00168   3 LTVTVIEAKNLPPKD-GNGTSDPYVKVYLLDGKQK---KKTKVVKNTLNPVWNETF 54

C2 domain first repeat present in Synaptotagmin-like proteins 1 and 2; 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. Slp1/JFC1 and Slp2/exophilin 4 promote granule docking to the plasma membrane. Additionally, their C2A domains are both Ca2+ independent, unlike Slp3 and Slp4/granuphilin which are Ca2+ dependent. It is thought that SHD (except for the Slp4-SHD) functions as a specific Rab27A/B-binding domain. In addition to Slps, rabphilin, Noc2, and Munc13-4 also function as Rab27-binding proteins. 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2028695507 603 KGNIQFAIEYVESLKELHVFVAQCKDLAAADVKKQRSDPYVKAYLLPDKGKMGKKKTLVVKKTLNPVYNEILR 675
Cdd:cd08393     1 QGSVQFALDYDPKLRELHVHVIQCQDLAAADPKKQRSDPYVKTYLLPDKSNRGKRKTSVKKKTLNPVFNETLR 73

C2 domain first repeat present in Synaptotagmin-like proteins; 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. Slp1/JFC1 and Slp2/exophilin 4 promote granule docking to the plasma membrane. Additionally, their C2A domains are both Ca2+ independent, unlike the case in Slp3 and Slp4/granuphilin in which their C2A domains are Ca2+ dependent. It is thought that SHD (except for the Slp4-SHD) functions as a specific Rab27A/B-binding domain. In addition to Slps, rabphilin, Noc2, and Munc13-4 also function as Rab27-binding proteins. It has been demonstrated that Slp3 and Slp4/granuphilin promote dense-core vesicle exocytosis. Slp5 mRNA has been shown to be restricted to human placenta and liver suggesting a role in Rab27A-dependent membrane trafficking in specific tissues. 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 2028695507 604 GNIQFAIEYVESLKELHVFVAQCKDLAAADVKKQRSDPYVKAYLLPDKGKMGKKKTLVVKKTLNPVYNEILR 675
Cdd:cd08521     1 GEIEFSLSYNYKTGSLEVHIKECRNLAYADEKKKRSNPYVKVYLLPDKSKQSKRKTSVKKNTTNPVFNETLK 72

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 2028695507 720 DLPLLRGSHL-NSFVKCTILPDTSRKSRQKTRAVGKTTNPIFNHTMVYDGFRPEDLMEACVELTVWDHYKL-TNQFLG 795
Cdd:cd04031    27 DLPPRDDGSLrNPYVKVYLLPDRSEKSKRRTKTVKKTLNPEWNQTFEYSNVRRETLKERTLEVTVWDYDRDgENDFLG 104

C2 domain second repeat present in Rabphilin and Double C2 domain; Rabphilin is found neurons and in neuroendrocrine cells, while Doc2 is found not only in the brain but in tissues, including mast cells, chromaffin cells, and osteoblasts. Rabphilin and Doc2s share highly homologous tandem C2 domains, although their N-terminal structures are completely different: rabphilin contains an N-terminal Rab-binding domain (RBD),7 whereas Doc2 contains an N-terminal Munc13-1-interacting domain (MID). 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 2028695507 689 MKLALQYVPEpvpgkklptTGEVHIWVKECLDL-PLLRGSHLNSFVKCTILPDTSRKSRQKTRAVGKTTNPIFNHTMVYD 767
Cdd:cd08384     2 ILVSLMYNTQ---------RRGLIVGIIRCVNLaAMDANGYSDPFVKLYLKPDAGKKSKHKTQVKKKTLNPEFNEEFFYD 72

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 2028695507 768 gFRPEDLMEACVELTVWDH-YKLTNQFLGGLRIGfgtgksygtevdwMDSTSEEVALWEKMVNSPNTWIEA 837
Cdd:cd08384    73 -IKHSDLAKKTLEITVWDKdIGKSNDYIGGLQLG-------------INAKGERLRHWLDCLKNPDKKIEA 129

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 2028695507  711 VHIWVKECLDLPLL-RGSHLNSFVKCTILPDTSRKsrQKTRAVGKTTNPIFNHTMVYDGFRPEDlmeACVELTVWDHYKL 789
Cdd:smart00239   2 LTVKIISARNLPPKdKGGKSDPYVKVSLDGDPKEK--KKTKVVKNTLNPVWNETFEFEVPPPEL---AELEIEVYDKDRF 76

                           90
                   ....*....|...
gi 2028695507  790 T-NQFLGGLRIGF 801
Cdd:smart00239  77 GrDDFIGQVTIPL 89

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 2028695507 604 GNIQFAIEYVESLKELHVFVAQCKDLAAADVKKQRSDPYVKAYLLPDKGKMGKKKTLVVKKTLNPVYNEILR 675
Cdd:cd08392     2 GEIEFALHYNFRTSCLEITIKACRNLAYGDEKKKKCHPYVKVCLLPDKSHNSKRKTAVKKGTVNPVFNETLK 73

C2 domain third repeat present in uncharacterized human KIAA1228-like proteins; KIAA proteins are uncharacterized human proteins. They were compiled by the Kazusa mammalian cDNA project which identified more than 2000 human genes. They are identified by 4 digit codes that precede the KIAA designation. Many KIAA genes are still functionally uncharacterized including KIAA1228. 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 third C2 repeat, C2C, and has a type-II topology.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2028695507 602 VKGNIQFAIEYVESLKELHVFVAQCKDLAAADvKKQRSDPYVKAYLLPDKGKMGKKKTLVVKKTLNPVYNEIL 674
Cdd:cd04030     1 PLGRIQLTIRYSSQRQKLIVTVHKCRNLPPCD-SSDIPDPYVRLYLLPDKSKSTRRKTSVKKDNLNPVFDETF 72

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 2028695507 604 GNIQFAIEYVESLKELHVFVAQCKDLAAADVKKQrSDPYVKAYLLPDKGKmgKKKTLVVKKTLNPVYNE 672
Cdd:cd08385     3 GKLQFSLDYDFQSNQLTVGIIQAADLPAMDMGGT-SDPYVKVYLLPDKKK--KFETKVHRKTLNPVFNE 68

C2 domain third repeat present in uncharacterized human KIAA1228-like proteins; KIAA proteins are uncharacterized human proteins. They were compiled by the Kazusa mammalian cDNA project which identified more than 2000 human genes. They are identified by 4 digit codes that precede the KIAA designation. Many KIAA genes are still functionally uncharacterized including KIAA1228. 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 third C2 repeat, C2C, and has a type-II topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2028695507 686 RGEMKLALQYVpepVPGKKLPTTgeVHiwvkECLDLPLLRGSHL-NSFVKCTILPDTSRKSRQKTRAVGKTTNPIFNHTM 764
Cdd:cd04030     2 LGRIQLTIRYS---SQRQKLIVT--VH----KCRNLPPCDSSDIpDPYVRLYLLPDKSKSTRRKTSVKKDNLNPVFDETF 72

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|..
gi 2028695507 765 VYDgFRPEDLMEACVELTVWDHYKLT---NQFLGGLRIGFGT 803
Cdd:cd04030    73 EFP-VSLEELKRRTLDVAVKNSKSFLsreKKLLGQVLIDLSD 113

C2A domain first 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 first C2 repeat, C2A, and has a type-I topology.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2028695507 603 KGNIQFAIEYVESLKELHVFVAQCKDLAAADVKKQrSDPYVKAYLLPDKG-KMgkkKTLVVKKTLNPVYNEIL 674
Cdd:cd08386     2 LGRIQFSVSYDFQESTLTLKILKAVELPAKDFSGT-SDPFVKIYLLPDKKhKL---ETKVKRKNLNPHWNETF 70

C2A domain first repeat present in Synaptotagmins 4 and 11; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. Synaptotagmins 4 and 11, class 4 synaptotagmins, are located in the brain. Their functions are unknown. They are distinguished from the other synaptotagmins by having and Asp to Ser substitution in their C2A domains. 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 2028695507 715 VKECLDLPLLRGSHLNS--FVKCTILPDtsRKSRQKTRAVGKTTNPIFNHTMVYDGFRPEDLMEACVELTV--WDHY 787
Cdd:cd08388    22 IIECRDLPAMDEQSGTSdpYVKLQLLPE--KEHKVKTRVLRKTRNPVYDETFTFYGIPYNQLQDLSLHFAVlsFDRY 96

C2 domain second repeat present in RAS p21 protein activator 3 (RasA3); RasA3 are members of GTPase activating protein 1 (GAP1), a Ras-specific GAP, which suppresses Ras function by enhancing the GTPase activity of Ras proteins resulting in the inactive GDP-bound form of Ras. In this way it can control cellular proliferation and differentiation. RasA3 contains an N-terminal C2 domain, a Ras-GAP domain, a plextrin homology (PH)-like domain, and a Bruton's Tyrosine Kinase (BTK) zinc binding domain. 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 2028695507 711 VHIWVKECLDLPLLRGShLNSFVKCTILPDTSRKSRQKTRAVGKTTNPIFNHTMVYDGFRP------------EDLMEAC 778
Cdd:cd04010     2 LSVRVIECSDLALKNGT-CDPYASVTLIYSNKKQDTKRTKVKKKTNNPQFDEAFYFDVTIDsspekkqfempeEDAEKLE 80

                          90       100
                  ....*....|....*....|..
gi 2028695507 779 VELTVWDHYKLTNQ-FLGGLRI 799
Cdd:cd04010    81 LRVDLWHASMGGGDvFLGEVRI 102

C2 domain second repeat present in Synaptotagmins 3, 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 3, a member of class 3 synaptotagmins, is located in the brain and localized to the active zone and plasma membrane. It functions as a Ca2+ sensor for fast exocytosis. It, along with synaptotagmins 5,6, and 10, has disulfide bonds at its N-terminus. 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 second C2 repeat, C2B, and has a type-I topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2028695507 687 GEMKLALQYvpepvpgkkLPTTGEVHIWVKECLDLP---LLRGShlNSFVKCTILPDTSRKSRQKTRAVGKTTNPIFNHT 763
Cdd:cd08403     1 GELMFSLCY---------LPTAGRLTLTIIKARNLKamdITGFS--DPYVKVSLMCEGRRLKKKKTSVKKNTLNPTYNEA 69

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 2028695507 764 MVYDgFRPEDLMEACVELTVWDHYKL-TNQFLGGLRIG---FGTGKSYGTEVdwMDSTSEEVALW 824
Cdd:cd08403    70 LVFD-VPPENVDNVSLIIAVVDYDRVgHNELIGVCRVGpnaDGQGREHWNEM--LANPRKPIAQW 131

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 2028695507 686 RGEMKLALQYvpepvpgkkLPTTGEVHIWVKECLDLPLLRGSHLNSFVKCTILPDTSRKSRQKTRAVGKTTNPIFNHTMV 765
Cdd:cd08409     1 LGDIQISLTY---------NPTLNRLTVVVLRARGLRQLDHAHTSVYVKVSLMIHNKVVKTKKTEVVDGAASPSFNESFS 71

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 2028695507 766 YdGFRPEDLMEACVELTVWDH-----YKLtnqfLGGLRIGfgtgksygtevDWMDSTSEEVALWEKMVNSPNTWIE 836
Cdd:cd08409    72 F-KVTSRQLDTASLSLSVMQSggvrkSKL----LGRVVLG-----------PFMYARGKELEHWNDMLSKPKELIK 131

C2 domain second repeat of Ras GTPase activating proteins (GAPs); RasGAPs suppress Ras function by enhancing the GTPase activity of Ras proteins resulting in the inactive GDP-bound form of Ras. In this way it can control cellular proliferation and differentiation. The proteins here all contain two tandem C2 domains, a Ras-GAP domain, and a pleckstrin homology (PH)-like domain. 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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2028695507 711 VHIWVKECLDLPLLRGSHLNSFVKCTILpDTSRKSRQKTRAVGKTTNPIFNHTMVYDGFRP------------EDLMEAC 778
Cdd:cd08675     1 LSVRVLECRDLALKSNGTCDPFARVTLN-YSSKTDTKRTKVKKKTNNPRFDEAFYFELTIGfsyekksfkveeEDLEKSE 79

                          90       100
                  ....*....|....*....|..
gi 2028695507 779 VELTVWDHYKLT-NQFLGGLRI 799
Cdd:cd08675    80 LRVELWHASMVSgDDFLGEVRI 101

C2 domain in Protein Kinase C (PKC) alpha and gamma; A single C2 domain is found in PKC alpha and gamma. The PKC family of serine/threonine kinases regulates apoptosis, proliferation, migration, motility, chemo-resistance, and differentiation. There are 3 groups: group 1(alpha, betaI, beta II, gamma) which require phospholipids and calcium, group 2 (delta, epsilon, theta, eta) which do not require calcium for activation, and group 3 (xi, iota/lambda) which are atypical and can be activated in the absence of diacylglycerol and calcium. 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.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2028695507 603 KGNIQFAIEYVEslKELHVFVAQCKDLAAADVKKQrSDPYVKAYLLPDKGKMGKKKTLVVKKTLNPVYNE 672
Cdd:cd04026     1 RGRIYLKISVKD--NKLTVEVREAKNLIPMDPNGL-SDPYVKLKLIPDPKNETKQKTKTIKKTLNPVWNE 67

C2 domain second repeat present in Synaptotagmins 3, 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 3, a member of class 3 synaptotagmins, is located in the brain and localized to the active zone and plasma membrane. It functions as a Ca2+ sensor for fast exocytosis. It, along with synaptotagmins 5,6, and 10, has disulfide bonds at its N-terminus. 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 second C2 repeat, C2B, and has a type-I topology.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 2028695507 604 GNIQFAIEYVESLKELHVFVAQCKDLAAADVKKqRSDPYVKAYLLPDKGKMGKKKTLVVKKTLNPVYNEIL 674
Cdd:cd08403     1 GELMFSLCYLPTAGRLTLTIIKARNLKAMDITG-FSDPYVKVSLMCEGRRLKKKKTSVKKNTLNPTYNEAL 70

C2 domain second repeat found in Multiple C2 domain and Transmembrane region Proteins (MCTP); plant subset; MCTPs are involved in Ca2+ signaling at the membrane. Plant-MCTPs are composed of a variable N-terminal sequence, four 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
                  ....*....|....*....|....*....|....*....|....*....|....
gi 2028695507 746 RQKTRAVGKTTNPIFNHTMVydgFRPEDLMEACVELTVWDHYKLTNQFLGGLRI 799
Cdd:cd08378    29 KGSTKAIERTSNPEWNQVFA---FSKDRLQGSTLEVSVWDKDKAKDDFLGGVCF 79

C2A domain first repeat present in Synaptotagmin 8; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. 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
                  ....*....|....*....|....*....|....*....|....*....|...
gi 2028695507 602 VKGNIQFAIEYVESLKELHVFVAQCKDLAAADVKKQrSDPYVKAYLLPDKGKM 654
Cdd:cd08387     1 TRGELHFSLEYDKDMGILNVKLIQARNLQPRDFSGT-ADPYCKVRLLPDRSNT 52

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 2028695507 686 RGEMKLALQYVPepvpgkklpTTGEVHIWVKECLDLPL--LRGSHlNSFVKCTILPDTSRKSRQKTRAVGKTTNPIFNHT 763
Cdd:cd08405     1 RGELLLSLCYNP---------TANRITVNIIKARNLKAmdINGTS-DPYVKVWLMYKDKRVEKKKTVIKKRTLNPVFNES 70

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 2028695507 764 MVYDgfRP-EDLMEACVELTVWDHYKLT-NQFLGGLRIGFGTGKSygtevdwmdstseEVALWEKMVNSPNT 833
Cdd:cd08405    71 FIFN--IPlERLRETTLIITVMDKDRLSrNDLIGKIYLGWKSGGL-------------ELKHWKDMLSKPRQ 127

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 2028695507 687 GEMKLALQYVPEpvpgkklptTGEVHIWVKECLDLPL--LRGSHLNSFVKCTILPDTSRKSRQKTRAVGKTTNPIFNHTM 764
Cdd:cd08392     2 GEIEFALHYNFR---------TSCLEITIKACRNLAYgdEKKKKCHPYVKVCLLPDKSHNSKRKTAVKKGTVNPVFNETL 72

                          90       100       110
                  ....*....|....*....|....*....|..
gi 2028695507 765 VYDgFRPEDLMEACVELTVWDHYKLTNQ-FLG 795
Cdd:cd08392    73 KYV-VEADLLSSRQLQVSVWHSRTLKRRvFLG 103

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 2028695507 604 GNIQFAIEYVESLKELHVFVAQCKDLAAADVKKQRSDPYVKAYLLPD---------KGKmgkkktlvvkkTLNPVYNE 672
Cdd:cd08390     1 GRLWFSVQYDLEEEQLTVSLIKARNLPPRTKDVAHCDPFVKVCLLPDerrslqskvKRK-----------TQNPNFDE 67

C2 domain second repeat in Munc13 (mammalian uncoordinated)-like proteins; C2-like domains are thought to be involved in phospholipid binding in a Ca2+ independent manner in both Unc13 and Munc13. Caenorabditis elegans Unc13 has a central domain with sequence similarity to PKC, which includes C1 and C2-related domains. Unc13 binds phorbol esters and DAG with high affinity in a phospholipid manner. Mutations in Unc13 results in abnormal neuronal connections and impairment in cholinergic neurotransmission in the nematode. Munc13 is the mammalian homolog which are expressed in the brain. There are 3 isoforms (Munc13-1, -2, -3) and are thought to play a role in neurotransmitter release and are hypothesized to be high-affinity receptors for phorbol esters. Unc13 and Munc13 contain both C1 and C2 domains. There are two C2 related domains present, one central and one at the carboxyl end. Munc13-1 contains a third C2-like domain. Munc13 interacts with syntaxin, synaptobrevin, and synaptotagmin suggesting a role for these as scaffolding proteins. 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 third C2 repeat, C2C, and has a type-II topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2028695507 720 DLPLLRGSHLN-SFVKCTILPDT--SRKSRQKTRAVGKTTNPIFNHTMVYDgFRPEDLME--ACVELTVWDHYKL-TNQF 793
Cdd:cd04009    27 NLLPLDSNGSSdPFVKVELLPRHlfPDVPTPKTQVKKKTLFPLFDESFEFN-VPPEQCSVegALLLFTVKDYDLLgSNDF 105

                  ..
gi 2028695507 794 LG 795
Cdd:cd04009   106 EG 107