The function of Ensembl gene identifier ENSG00000150681 (RGS18, regulator of G protein signaling 18) is as follows. Inhibits signal transduction by increasing the GTPase activity of G protein alpha subunits thereby driving them into their inactive GDP-bound form. Binds to G(i) alpha-1, G(i) alpha-2, G(i) alpha-3 and G(q) alpha. {ECO:0000269|PubMed:11042171, ECO:0000269|PubMed:11955952}.