Acetylcholine-gated chloride channel subunit. Forms functional homopentameric (in vitro) and functional heteropentameric ion channels with acc-3 and acc-4 ion channel subunits. Currents in channels are triggered in response to acetylcholine, but not in response to GABA, glutamate, glycine, histamine or dopamine. Homopentamer (in vitro). Forms heteropentamers composed of acc-1 and acc-4 or acc-1 and acc-3. Both homopentamers and heteropentamers form functional ion channels. Expressed in a subset of cholinergic motor neurons including cholinergic motor neurons in the ventral cord, the retrovesicular ganglion and in head neurons such as the SMD, RMD motor neurons, the AVA and AVE command interneurons and the SAA neurons. Also expressed in a small number of glutamatergic neurons including the pharyngeal neurons MI and M3, the PLM neurons and a pair of neurons in the lateral ganglion. Grossly normal movement. Belongs to the ligand-gated ion channel (TC 1.A.9) family.