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: 2-Oct-2020
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:
CAG07403      542 ILAVYLDQAQDLPmrk-gnKDPSPIVQISIqd-tTRESKTCYGTNNPIWSDAFTFFIqdprkQDLDIQVKDDDr-----s 614  Tetraodon nig...
CAG07403      894 MLFVYVERAHGLPlkk-sgKEPKVGADVLLrn-vSHRTKVCERSTSPRWDEGFHFLVrdpkeETLTVKVISGVsaslvwg 971  Tetraodon nig...
BAC32020      786 LLSVFLERAEDLPlrk-gtKPPSPYATITVge-tSHKTKTVSQSSAPVWEESASFLIrkphaESLELQACFIHll---fl 860  house mouse
Q5RAG2        799 LLSIYMERAEDLPlrk-gtKHPSPYATLTVgd-tSHKTKTVSQTSAPVWDESASFLIrkphtENLELQVRGEGt------ 870  Sumatran oran...
CAE51055      962 LFFILLERAHNLPlkk-sgKEPKAAAELVLgd-iTHKTKVCERSMSPQWSEAFHFLVhkpteEILIIKLSSAFe------ 1033 zebrafish
XP_699731     772 LLFVYVEQAYELPlkk-sgKEPKVGAELVLgg-tSRKTTVCDRTSTPKWDEAFYFLVrdplnEDLIVKLSHNWd------ 843  zebrafish
NP_741181     424 LLMVYIDSVADLPypk-skLEPSPFVEVSLgk-eTQRTPVKVKTVNPLFQSKFLFFVrhlegQELKFEAVDDGt-----r 496  nematode
XP_001897176  425 LLMIFIDSVSDLPypk-akLEPSPYIMVSVgk-dFQQTPTKIRTVNPLFQIKILFFVryperQEVKFEAIDHTt-----k 497  agent of lymp...
AAX26056       71 FLYVVIEQAHNLPsvk-qlQEPSPFCNIHLgr-dYQTNEVKEKTQNPVWNSVHHFLVsdpnvDILQLIIRDSRt-----e 143  Schistosoma j...
XP_002123167  115 FLNIYVDGAQNLPefnqecYDANPQLKITLpgkePLKTRVAMHTNNPVWEENFHVLIshpelDLVTFQMENDHg-----n 189  Ciona intesti...
CAG07403      615 LSLGTLTIPLMRLLgsp-eltMDQWFQLENSGS 646  Tetraodon nigroviridis
CAG07403      972 QALGSLTLPLRDVLldp-gmvLDRWFNVDGALP 1003 Tetraodon nigroviridis
BAC32020      861 FERGREQRTVFEFEvfg-vnsFPPCGNLWATAH 892  house mouse
Q5RAG2        871 GVLGSLSLPLSELLvad-qlcLDRWFTLNSGQG 902  Sumatran orangutan
CAE51055     1034 QPLGSLVLPIRELLskt-dllMDQWLSLDGAAA 1065 zebrafish
XP_699731     844 FSVGSVVIPIKELLsep-dllLDQWLDLDGASP 875  zebrafish
NP_741181     497 RSLGSLNIPLTTLLkep-nleQNQQMHMLTLGV 528  nematode
XP_001897176  498 RSLGEFVLPLKTILlepnlelFEQTFPLTLGVH 530  agent of lymphatic filariasis
AAX26056      144 KKLGSCSIHLKTLLtqk-tlsVTQPFTLQDTGR 175  Schistosoma japonicum
XP_002123167  190 QNLGFMKFPLKHLLraq-dmtIEHPFTLKSSGP 221  Ciona intestinalis
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