Synaptotagmin 1/2 (IPR015428)

Short name: Synaptotagmin1/2

Overlapping homologous superfamilies

Family relationships



Synaptotagmins are synaptic vesicle membrane proteins found in abundance in nerve cells and some endocrine cells [PMID: 7697723, PMID: 7961887]. The amino acid sequence of synaptotagmin comprises a single transmembrane region with a short vesicular N-terminal region, and a cytoplasmic C-terminal region containing 2 internal repeats similar to the C2 regulatory domain of protein kinase C. The protein is believed to be important in the docking and fusion of synaptic vesicles with the plasma membrane, i.e. with neurotransmitter release [PMID: 7697723, PMID: 7961887].

Synaptotagmin 1 (originally called p65) and synaptotagmin 2 were the first to members identified in the synaptotagmin family [PMID: 1856191, PMID: 2333096]. Synaptotagmin 1 may have a regulatory role in the membrane interactions during trafficking of synaptic vesicles at the active zone of the synapse [PMID: 7479985]. It binds acidic phospholipids with a specificity that requires the presence of both an acidic head group and a diacyl backbone [PMID: 12867508, PMID: 15056279]. It has been shown to function as a Ca2+ sensor on the synaptic vesicle surface, therefore to regulate Ca2+ dependent neurotransmitter release [PMID: 1589771, PMID: 11242035].

Synaptotagmin-2 (Syt2) is a synaptic vesicle protein that functions as a calcium sensor for neurotransmission [PMID: 1856191, PMID: 7791877]. It is the major isoform of the synaptotagmin family at mammalian neuromuscular junctions (NMJs) [PMID: 17192432]. Synaptotagmin 2 regulates neurotransmitter release at human peripheral motor nerve terminals. Mutations in syt2 are an important cause of congenital myasthenic syndromes [PMID: 25192047].

GO terms

Biological Process

GO:0007269 neurotransmitter secretion

Molecular Function

GO:0005544 calcium-dependent phospholipid binding

Cellular Component

GO:0008021 synaptic vesicle

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.