Synaptotagmin-2
Domain
The first C2 domain mediates Ca(2+)-dependent phospholipid binding (PubMed:7961887).
The second C2 domain mediates interaction with Stonin 2. The second C2 domain mediates phospholipid and inositol polyphosphate binding in a calcium-independent manner (PubMed:7961887).
(Microbial infection) Binding to BoNT/B induces formation of an alpha-helix in the membrane-proximal extracytoplasmic domain (PubMed:17167418, PubMed:23807078).
Function
Exhibits calcium-dependent phospholipid and inositol polyphosphate binding properties (PubMed:7961887). May have a regulatory role in the membrane interactions during trafficking of synaptic vesicles at the active zone of the synapse (PubMed:7961887). Plays a role in dendrite formation by melanocytes (By similarity).
(Microbial infection) Receptor for C.botulinum neurotoxin type B (BoNT/B, botB); interaction is improved in the presence of gangliosides (PubMed:14504267). The toxin binds via the vesicular domain (residues 47-60) (PubMed:14504267, PubMed:17167418, PubMed:23807078).
(Microbial infection) Receptor for C.botulinum neurotoxin type G (BoNT/G, botG); gangliosides are not required for (or only very slightly improve) binding to a membrane-anchored receptor fragment (PubMed:20219474). The toxin binds via the vesicular domain (residues 47-55) (PubMed:20219474).
Post-translational modifications
Phosphorylation at Thr-202 by WNK1, changes the calcium requirement for SYT2-binding to phospholipid membranes.
Sequence Similarities
Belongs to the synaptotagmin family.
Cellular localization
- Cytoplasmic vesicle
- Secretory vesicle
- Synaptic vesicle membrane
- Single-pass membrane protein
- Cytoplasmic vesicle
- Secretory vesicle
- Chromaffin granule membrane
- Single-pass membrane protein
- Cytoplasm
Alternative names
Synaptotagmin-2, Inositol polyphosphate-binding protein, Synaptotagmin II, IP4-binding protein, IP4BP, SytII, Syt2