Exhibits calcium-dependent phospholipid and inositol polyphosphate binding properties. May have a regulatory role in the membrane interactions during trafficking of synaptic vesicles at the active zone of the synapse. Plays a role in dendrite formation by melanocytes. (Microbial infection) Receptor for C.botulinum neurotoxin type B (BoNT/B, botB); unlike the case with BoNT/B interaction is not improved in the presence of gangliosides (PubMed:17167421). The toxin binds to the vesicular domain of Syt2 (residues 1-61) (PubMed:15123599). (Microbial infection) Receptor for C.botulinum neurotoxin type G (BoNT/G, botG); unlike the case with BoNT/B interaction is not improved in the presence of gangliosides (PubMed:15123599). The toxin binds to the vesicular domain of Syt2 (residues 1-61) (PubMed:15123599). Binds 3 Ca(2+) ions per subunit. The ions are bound to the C2 domains. Homotetramer (Probable). Interacts with SCAMP5 (By similarity). Interacts with STON2 (By similarity). Interacts with PRRT2 (By similarity). (Microbial infection) Interacts with C.botulinum neurotoxin type G (BoNT/G, botG). Predominantly expressed in brain regions such as the spinal cord, brain stem and cerebellum (PubMed:1856191). The first C2 domain mediates Ca(2+)-dependent phospholipid binding. The second C2 domain mediates interaction with Stonin 2. The second C2 domain mediates phospholipid and inositol polyphosphate binding in a calcium-independent manner. (Microbial infection) Binding to BoNT/B induces formation of an alpha-helix in the membrane-proximal extracytoplasmic domain (PubMed:17167421). Belongs to the synaptotagmin family.