Interaction of G protein Gβγ dimers with small GTP‐binding proteins of the Rho family

Abstract

Gβγ dimers of heterotrimeric G proteins have been shown to be important for the translocation of cytosolic proteins to membranes. The involvement of Gβγ in those signaling processes mediated by small GTP‐binding proteins of the Rho family was studied using purified proteins. We showed specific binding of bovine brain Gβγ to immobilized GST‐Rho fusion proteins. In addition, brain Gβγ, but not transducin Gβγ, was able to inhibit GTPγS binding to GST‐Rho in a concentration‐dependent manner. GTPγS binding to GST‐Rac was also decreased by brain Gβγ whereas nucleotide binding to GST‐Cdc42 was not changed. We conclude that Gβγ dimers may participate in the process of membrane attachment and/or other regulations of Rho and Rac.