Probable acetylcholine-gated chloride channel regulatory subunit. Does not have ion channel activity alone as a homopentamer, but forms a functional heteropentameric ion channel with acc-1. Does not form a functional homopentameric ion channel. Forms a functional heteropentameric ion channel composed of acc-1 and acc-3. May interact with acc-2; the interaction does not result in significant heteropentameric ion channel activity. Grossly normal movement. Belongs to the ligand-gated ion channel (TC 1.A.9) family.