Inhibits signal transduction by increasing the GTPase activity of G protein alpha subunits thereby driving them into their inactive GDP-bound form. Binds to GNAT1. Involved in phototransduction; key element in the recovery phase of visual transduction (By similarity).
Subcellular locations: Membrane
Isoform 3 is targeted to the membrane via its interaction with RGS9BP.
Highly expressed in the caudate and putamen, lower levels found in the hypothalamus and nucleus accumbens and very low levels in cerebellum. Not expressed in globus pallidus or cingulate cortex. Isoform 2 is expressed predominantly in pineal gland and retina. Isoform 3 is expressed in retina (abundant in photoreceptors).