Plays a role in vesicle maturation during exocytosis as a target of the diacylglycerol second messenger pathway. Is involved in neurotransmitter release by acting in synaptic vesicle priming prior to vesicle fusion and participates in the activity-depending refilling of readily releasable vesicle pool (RRP) (By similarity). Essential for synaptic vesicle maturation in a subset of excitatory/glutamatergic but not inhibitory/GABA-mediated synapses. In collaboration with UNC13A, facilitates neuronal dense core vesicles fusion as well as controls the location and efficiency of their synaptic release (PubMed:23229896). Interacts with RIMS1. Localized to synapses (By similarity). Translocates to the Golgi in response to phorbol ester binding. The C2 domains are not involved in calcium-dependent phospholipid binding. Belongs to the unc-13 family.