Ligand-gated chloride channel subunit which is a component of the heteropentameric receptor for GABA, the major inhibitory neurotransmitter in the brain. May be involved in GABA-A receptor assembly, and GABA-A receptor immobilization and accumulation by gephyrin at the synapse. Generally pentameric. There are five types of GABA(A) receptor chains: alpha, beta, gamma, delta, and rho. Belongs to the ligand-gated ion channel (TC 1.A.9) family. Gamma-aminobutyric acid receptor (TC 1.A.9.5) subfamily. GABRA5 sub-subfamily.