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. Colocalizes with RIMS1 and BSN in early stages of synapse formation. Predominantly expressed in brain, including hippocampus, cortex, cerebellum, amygdala and olfactory bulb. Detected at embryonic day E18 and at later stages. The expression does not significantly change during the developmental stages tested.