Synaptotagmin 1 is a 60 kDa member of the synaptotagmin family, expressed in membranes of synaptic vesicles in rostral, phylogenetically younger brain regions and in some endocrine tissues. Ca2+ is bound by synaptogamin whose C2 domains then bind phospholipids, trafficking vesicles to the synaptic membrane and exocytosis. This results in fast synchronous neurotransmitter release. Synaptotagmin also binds neurexins, syntaxin and AP2 independently of Ca2+ binding. Phosphorylation of synaptotagmin by protein kinases is thought to modulate its activity.Synonyms: SVP65, SYT, SYT1, Synaptotagmin I, Synaptotagmin1, SytI, p65