Domain

Synaptotagmin (IPR001565)

Short name: Synaptotagmin

Domain relationships

None.

Description

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].

The 2 synaptotagmin C2 domains have been shown to have different functions: C2A binds phospholipid in a calcium-dependent manner, while C2B binds inositol polyphosphate and phospholipid irrespective of the presence of Ca2+ [PMID: 7961887]. The structure of C2 domains in synaptotagmin I has been deduced: the C2 polypeptide forms an 8-stranded beta-sandwich constructed around a conserved 4-stranded motif, designated a C2 key [PMID: 7697723]. The calcium binding region is a cup-shaped depression formed by the N- and C-terminal loops of the C2-key motif, while the site of phospholipid interaction is thought to be a polybasic sequence on the hairpin loop connecting strands 3 and 4 [PMID: 7697723].

GO terms

Biological Process

GO:0006810 transport

Molecular Function

GO:0005215 transporter activity

Cellular Component

GO:0016020 membrane
GO:0008021 synaptic vesicle

Contributing signatures

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