Synaptotagmin 1
（重定向自SYT）
![Molecular machinery driving exocytosis in neurotransmitter release: the core SNARE complex (formed by four α-helices contributed by synaptobrevin, syntaxin and SNAP-25) and the Ca2+ sensor synaptotagmin.[1]](/uploads/202502/14/Exocytosis-machinery2528.jpg)
Synaptotagmin 1 (or synaptotagmin) is a Ca sensor in the membrane of the pre-synaptic axon terminal, coded by gene SYT1 (previously SYT) at 12q21.2 (MIM:185605).
Synaptotagmins (SYTs) constitute a family of membrane-trafficking proteins that are characterized by an N-terminal transmembrane region (TMR), a variable linker, and two C-terminal C2 domains - C2A and C2B. There are 15 members in the mammalian synaptotagmin family. There are several C2-domain containing protein families that are related to synaptotagmins, including transmembrane (Ferlins, E-Syts, and MCTPs) and soluble (RIMs, Munc13s, synaptotagmin-related proteins and B/K) proteins.