A G protein γ subunit-like domain shared between RGS11 and other RGS proteins specifies binding to Gβ5 subunits

Regulators of G protein signaling (RGS) proteins act as GTPase-activating proteins (GAPs) toward the α subunits of heterotrimeric, signal-transducing G proteins. RGS11 contains a G protein γ subunit-like (GGL) domain between its Dishevelled/Egl-10/Pleckstrin and RGS domains. GGL domains are also found in RGS6, RGS7, RGS9, and the Caenorhabditis elegans protein EGL-10. Coexpression of RGS11 with different G β subunits reveals specific interaction between RGS11 and G β5 . The expression of mRNA for RGS11 and G β5 in human tissues overlaps. The G β5 /RGS11 heterodimer acts as a GAP on G αo , apparently selectively. RGS proteins that contain GGL domains appear to act as GAPs for G α proteins and form complexes with specific G β subunits, adding to the combinatorial complexity of G protein-mediated signaling pathways.