THE BETA-ADRENERGIC-RECEPTOR KINASE INTERACTS WITH THE AMINO-TERMINUSOF THE G-PROTEIN BETA-SUBUNIT

Desensitization of G protein-coupled receptors involves phosphorylatio n of the receptors by G protein-coupled receptor kinases, such as the beta-adrenerse receptor kinase (beta ARK). beta ARK activity depends u pon its translocation from the cytoplasm to the membrane. The beta gam ma subunits of G proteins bind to beta ARK and recruit the kinase to t he membrane. The G beta gamma binding domain is localized to a carboyl terminal region of beta ARK but the beta ARK binding domain of G beta gamma is not known, We used the yeast two-hybrid assay to characteriz e the interaction between G beta and beta ARK. We demonstrate an inter action between the carboxyl terminus of beta ARK and G beta 2. The str ength of this interaction is increased when the VP16 transactivation d omain is placed on the carboxyl end of G beta(2), indicating that an a ccessible G beta 2 amino terminus is important for its interaction wit h beta ARK. In addition, we show that amino acids 1 to 145 of G beta 2 are sufficient for beta ARK binding. (C) 1997 Academic Press.