Synaptotagmin-1（SYT1） is a member of the synaptotagmin family， which contains two C2 domains. The synaptotagmins are integral membrane proteins of synaptic vesicles assumed to function as Ca（2+） sensors in the process of vesicular trafficking and exocytosis. SYT1 is the principal regulator responsible for allowing the human brain to release neurotransmitters. SYT1 may have a regulatory role in the membrane interactions during trafficking of synaptic vesicles at the active zone of the synapse. SYT1 binds acidic phospholipids with a specificity which entails the presence of both an acidic head group and a diacyl backbone. SYT1 can also bind to at least 3 additional proteins in a Ca2+-independent manner； these being neurexins， syntaxin and AP2.
