Theta subunit of the heteropentameric ligand-gated chloride channel gated by gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the brain (PubMed:10449790, PubMed:16412217). GABA- gated chloride channels, also named GABA(A) receptors (GABAAR), consist of five subunits arranged around a central pore and contain GABA active binding site(s) located at the alpha and beta subunit interfaces (By similarity). When activated by GABA, GABAARs selectively allow the flow of chloride anions across the cell membrane down their electrochemical gradient (PubMed:10449790, PubMed:16412217). {ECO:0000250|UniProtKB:P47870, ECO:0000269|PubMed:10449790, ECO:0000269|PubMed:16412217}. This is the function of GABRQ (gamma-aminobutyric acid type A receptor subunit theta, Ensembl gene identifier ENSG00000268089).