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, predominantly in the cerebellum. First detected at birth, after which expression level is steadily increasing until it reaches a plateau at P15. The C2 domains are not involved in calcium-dependent phospholipid binding. Belongs to the unc-13 family.