The protein encoded by this gene is a presynaptic protein that interacts with RAB3, a protein important for normal neurotransmitter release. The encoded protein can also bind several other synaptic proteins, including UNC-13 homolog B, ELKS/Rab6-interacting/CAST family member 1, and synaptotagmin 1. This protein is involved in synaptic membrane exocytosis. Polymorphisms in this gene have been associated with degenerative lumbar scoliosis. [provided by RefSeq, Feb 2017].