Plays a role in the control of regulated secretion in neural and endocrine cells, enhancing selectively low-frequency neurotransmission. Positively regulates vesicle fusion by maintaining the readily releasable pool of secretory vesicles.
(Microbial infection) Receptor for C.botulinum neurotoxin type A (BoNT/A, botA); the toxin probably binds via extracellular loop 4 . Recognition by BoNT/A relies on both protein-protein and protein-N-glycosylation; glycosylation of Asn-559 increases its affinity for BoNT/A . Also serves as a receptor for the closely related C.botulinum neurotoxin type A2; glycosylation is not essential but enhances the interaction .
(Microbial infection) Possible receptor for C.botulinum neurotoxin type D (BoNT/D, botD); note that type D does not usually infect humans.
Subcellular locations: Cytoplasmic vesicle, Secretory vesicle, Synaptic vesicle membrane
Enriched in small synaptic vesicles and adrenal microsomes, not present in chromaffin granules. Associated with both insulin granules and synaptic-like microvesicles in insulin-secreting cells of the pancreas.