Conserved Protein Domain Family
C2B_Synaptotagmin-like

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cd04050: C2B_Synaptotagmin-like 
C2 domain second repeat present in Synaptotagmin-like proteins
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 second C2 repeat, C2B, and has a type-I topology.
Statistics
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PSSM-Id: 176015
View PSSM: cd04050
Aligned: 32 rows
Threshold Bit Score: 108.035
Threshold Setting Gi: 196015541
Created: 11-Jan-2005
Updated: 17-Jan-2013
Structure
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Aligned Rows:
PubMed ReferencesClick to see Conserved Features Help

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 47228671   542 ILAVYLDQAQDLPmrk-gnKDPSPIVQISIqd-tTRESKTCYGTNNPIWSDAFTFFIqdprkQDLDIQVKDDDr-----s 614
gi 47228671   894 MLFVYVERAHGLPlkk-sgKEPKVGADVLLrn-vSHRTKVCERSTSPRWDEGFHFLVrdpkeETLTVKVISGVsaslvwg 971
gi 26336675   786 LLSVFLERAEDLPlrk-gtKPPSPYATITVge-tSHKTKTVSQSSAPVWEESASFLIrkphaESLELQACFIHll---fl 860
gi 97049267   799 LLSIYMERAEDLPlrk-gtKHPSPYATLTVgd-tSHKTKTVSQTSAPVWDESASFLIrkphtENLELQVRGEGt------ 870
gi 37650715   962 LFFILLERAHNLPlkk-sgKEPKAAAELVLgd-iTHKTKVCERSMSPQWSEAFHFLVhkpteEILIIKLSSAFe------ 1033
gi 189520791  772 LLFVYVEQAYELPlkk-sgKEPKVGAELVLgg-tSRKTTVCDRTSTPKWDEAFYFLVrdplnEDLIVKLSHNWd------ 843
gi 25148904   424 LLMVYIDSVADLPypk-skLEPSPFVEVSLgk-eTQRTPVKVKTVNPLFQSKFLFFVrhlegQELKFEAVDDGt-----r 496
gi 170584790  425 LLMIFIDSVSDLPypk-akLEPSPYIMVSVgk-dFQQTPTKIRTVNPLFQIKILFFVryperQEVKFEAIDHTt-----k 497
gi 76154604    71 FLYVVIEQAHNLPsvk-qlQEPSPFCNIHLgr-dYQTNEVKEKTQNPVWNSVHHFLVsdpnvDILQLIIRDSRt-----e 143
gi 198414796  115 FLNIYVDGAQNLPefnqecYDANPQLKITLpgkePLKTRVAMHTNNPVWEENFHVLIshpelDLVTFQMENDHg-----n 189
                          90       100       110
                  ....*....|....*....|....*....|...
gi 47228671   615 LSLGTLTIPLMRLLgsp-eltMDQWFQLENSGS 646
gi 47228671   972 QALGSLTLPLRDVLldp-gmvLDRWFNVDGALP 1003
gi 26336675   861 FERGREQRTVFEFEvfg-vnsFPPCGNLWATAH 892
gi 97049267   871 GVLGSLSLPLSELLvad-qlcLDRWFTLNSGQG 902
gi 37650715  1034 QPLGSLVLPIRELLskt-dllMDQWLSLDGAAA 1065
gi 189520791  844 FSVGSVVIPIKELLsep-dllLDQWLDLDGASP 875
gi 25148904   497 RSLGSLNIPLTTLLkep-nleQNQQMHMLTLGV 528
gi 170584790  498 RSLGEFVLPLKTILlepnlelFEQTFPLTLGVH 530
gi 76154604   144 KKLGSCSIHLKTLLtqk-tlsVTQPFTLQDTGR 175
gi 198414796  190 QNLGFMKFPLKHLLraq-dmtIEHPFTLKSSGP 221
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