Synaptotagmin-1 and Synaptotagmin-2 (Syt1 and Syt2)

Synaptotagmin-1 and Synaptotagmin-2 are integral membrane proteins of synaptic vesicles in neurons, functioning as principal calcium sensors that trigger rapid, synchronous neurotransmitter release at synapses, particularly at neuromuscular junctions and other fast-conducting synapses in the central and peripheral nervous systems[1][3][4]. Both isoforms share a conserved structure with two C2 calcium-binding domains and play partially overlapping but distinct roles: Synaptotagmin-1 predominates in the central nervous system and immature nerve terminals, while Synaptotagmin-2 is particularly abundant in mature motor neuron terminals at neuromuscular junctions and selected brain regions. Deletion or dysfunction of Synaptotagmin-2 causes severe and often lethal impairment of synaptic transmission and motor function, highlighting their essential role in neuronal communication[1][5]. Synaptotagmin-1, together with Synaptotagmin-2, enables precise timing of neurotransmitter release in response to calcium influx, a process critical for muscle contraction and normal motor behavior[1][2][4][5].

Other names

Synaptotagmin ISynaptotagmin IISyt ISyt IISYT1SYT2Ca2+ sensor for fast neurotransmitter release

Drugs/toxins affecting the SNARE complex or disrupting calcium-triggered neurotransmitter release would functionally affect synaptotagmin-1 and -2