The function of RGS17 (regulator of G protein signaling 17, Ensembl gene identifier ENSG00000091844) is as follows. Regulates G protein-coupled receptor signaling cascades, including signaling via muscarinic acetylcholine receptor CHRM2 and dopamine receptor DRD2. Inhibits signal transduction by increasing the GTPase activity of G protein alpha subunits, thereby driving them into their inactive GDP-bound form (PubMed:15096504). Binds selectively to GNAZ and GNAI2 subunits, accelerates their GTPase activity and regulates their signaling activities. Negatively regulates mu-opioid receptor-mediated activation of the G proteins (By similarity). .