Skip to main content
. Author manuscript; available in PMC: 2011 Feb 1.
Published in final edited form as: Curr Opin Cell Biol. 2010 Jun 3;22(4):496–505. doi: 10.1016/j.ceb.2010.05.001

Table 1.

Properties of synaptotagmins

Protein Class Localization Ca2+-binding Special properties Function References
Syt 1 A Synaptic vesicles LDCVs Yes N-terminal N-glycosylation Phospholipids and SNARE binding Ca2+-sensor for fast exocytosis 6,10,12,31-33, 39-43,74
Syt2 A Synaptic vesicles LDCVs? Yes N-terminal N-glycosylation Phospholipid and SNARE binding Ca2+-sensor for fast exocytosis 8,9,31-33,43, 44,54,74
Syt3 C Plasma membrane Yes Disulfide bonds at N-terminus Phospholipid binding Ca2+-sensor for exocytosis? 31-33,74
Syt4 D Postsynaptic? No* Aspartate to Serine substitution in C2A domain loops unknown*; not essential for survival 73,74
Syt5 C Plasma membrane Yes Disulfide bonds at N-terminus Phospholipid bindings Ca2+-sensor for exocytosis? 31-33,74
Syt6 C Plasma membrane Yes Disulfide bonds at N-terminus Phospholipid binding Ca2+-sensor for exocytosis? 31,74
Syt7 B LDCVs Synapses? Yes Multiple splicing isoforms Phospholipid and SNARE binding Ca2+-sensor for LDCV exocytosis 47-50,74
Syt8 F primarily GIT tract No Only Syt isoform that is expressed at highest levels outside of brain Not known 31,74
Syt9 A Synaptic vesicles Yes Phospholipid and SNARE binding Ca2+-sensor for fast exocytosis 43,74
Syt10 C Plasma membrane Yes Disulfide bonds at N-terminus Phospholipid binding Ca2+-sensor for exocytosis? 31,74
Syt11 D Unknown No Similar to Syt4, but more abundant unknown 74
Syt12 F Synaptic vesicles No Phosphorelated by PKA May regulate miniature release 31,74,75
Syt13 F Not known No Not known 31,74
Syt14 E Not known No Syt14-16 form a group of related and evolutionarily conserved isoforms Not known 76
Syt15 E Not known No Syt14-16 form a group of related and evolutionarily conserved isoforms Not known 76
Syt16 E Not known No Syt14-16 form a group of related and evolutionarily conserved isoforms Not known 76

Synaptotagmins are defined by the presence of an N-terminal transmembrane region, and two C-terminal C2-domains. Each synaptotagmin protein is encoded by a different gene; some are differentially spliced (e.g., Syt7). Classes of synaptotagmins are proposed defined by sequence homologies, conservation, and functions

*

Syt4 binds to Ca2+ in Drosophila and has been implicated in postsynaptic exocytosis.