May play a role in vesicle maturation during exocytosis as a target of the diacylglycerol second messenger pathway. May be involved in the regulation of synaptic transmission at parallel fiber - Purkinje cell synapses (By similarity). Interacts with STX1A and/or STX1B1, VAMP2 and SNAP25. Localized to presynaptic structures. Exclusively expressed in brain. The C2 domains are not involved in calcium-dependent phospholipid binding. Belongs to the unc-13 family. Contaminating sequence. Sequence of unknown origin in the N-terminal part.