Intrinsic membrane protein of small synaptic vesicles. Neuronal synaptic vesicles. In vitro integrates into vesicles co- and post-translationally (PubMed:8197120). (Microbial infection) Targeted and hydrolyzed by C.botulinum neurotoxin type D (BoNT/D, botD) which hydrolyzes the 49-Lys-|-Ile-50 bond and probably inhibits neurotransmitter release (PubMed:8197120). (Microbial infection) Targeted and hydrolyzed by C.botulinum neurotoxin type F (BoNT/F, botF) which hydrolyzes the 48-Gln-|-Lys-49 bond and probably inhibits neurotransmitter release (PubMed:8197120). (Microbial infection) Targeted and hydrolyzed by C.tetani toxin (tetX) which hydrolyzes the 66-Gln-|-Phe-67 bond and probably inhibits neurotransmitter release (PubMed:8197120). Belongs to the synaptobrevin family. It is not known if C.botulinum or C.tetani infect this organism.