Interaction of human retinal RGS with G-protein α-subunits

Abstract

A novel family of RGS proteins negatively regulates signaling via heterotrimeric G-proteins by accelerating the GTPase activity of G-protein α subunits. We have investigated interaction of human retinal RGS protein (hRGSr) with in vitro translated G(α) subunits: G(tα) G(iα1), G(oα) and G(sα). hRGSr binds well to G(tα), G(iα1) and G(oα) in the presence of AIF4-, but does not interact with G(sα). The N- and C-terminally truncated G(α) subunits interact with hRGSr similarly to the intact G(α) polypeptides. Analysis of interaction between hRGSr and G(oα)/ G(sα) chimeras suggests that a region of G(oα), G(oα)22-212, contains major structural determinants for binding to RGS proteins.