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. Interacts with STX1A and/or STX1B1, VAMP2 and SNAP25. Localized to presynaptic structures. Restricted to cerebellum, predominantly in the granule cell layer. Almost exclusively present in the molecular layer in which the parallel fiber axons of granule cells terminate on dendrites of Purkinje neurons (at protein level). The C2 domains are not involved in calcium-dependent phospholipid binding. Mutant mice showed no obvious physical or behavioral abnormalities. Some deficiency in motor learning can be observed, compared to wild type, in a motor performance and learning test on a rotating rod, but only at high rotation speed. Belongs to the unc-13 family. Contaminating sequence. Sequence of unknown origin in the N- terminal and C-terminal parts.