Thought to be involved in the organization of the cytomatrix at the nerve terminals active zone (CAZ) which regulates neurotransmitter release. Seems to act together with BSN. May recruit liprin-alpha proteins to the CAZ. Interacts with BSN, ERC1, PPFIA1, PPFIA2, PPFIA3 and PPFIA4. Interacts through its C-terminus with the PDZ domain of RIMS1. Part of a complex consisting of ERC2, RIMS1 and UNC13A. Localized to the active zone of presynaptic density. Expressed throughout the central nervous system, including hippocampus, cortex, cerebellum and olfactory bulb. Due to intron retention. Extended N-terminus.