RGS proteins constitute a newly appreciated and large group of negative regulators of G protein signaling. Four members of the RGS family act as GTPase-activating proteins (GAPs) with apparent specificity for members of the Giα subfamily of G protein subunits. We demonstrate here that two RGS proteins, RGS4 and GAIP, also act as GAPs for Gqα, the Gα protein responsible for activation of phospholipase Cβ. Furthermore, these RGS proteins block activation of phospholipase Cβ by guanosine 5′-(3-O-thio)triphosphate-Gqα. GAP activity does not explain this effect, which apparently results from occlusion of the binding site on Gα for effector. Inhibitory effects of RGS proteins on G protein-mediated signaling pathways can be demonstrated by simple mixture of RGS4 or GAIP with plasma membranes.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jan 21 1997|
ASJC Scopus subject areas