A structural constituent of presynaptic active zone. Involved in synaptic vesicle priming. Located in GABA-ergic synapse and glutamatergic synapse. Is active in presynaptic active zone cytoplasmic component. Is expressed in several structures, including gut; limb; nervous system; sensory organ; and urinary system. Orthologous to human ERC2 (ELKS/RAB6-interacting/CAST family member 2). [provided by Alliance of Genome Resources, Apr 2022]