the activated receptor, augmenting GRK activity to regulate the activated receptor. The amino terminal RGS-homology (RH) domain of GRK2 and GRK3 binds to heterotrimeric G protein subunits of the Gq family to reduce Gq signaling by sequestering active G proteins away from their effector proteins such as phospholipase C-beta; but the GRK2 and GRK3 RH domains are unable to function as GTPase-activating proteins (as do traditional RGS proteins) to turn off G protein signaling. Interactions GRK2 has been shown to interact with numerous protein partners, including: G protein βγ complex G protein GNAQ family members GIT1 and GIT2 PDE6G PRKCB1 Src See also G protein-coupled receptor kinases G protein desensitization (medicine) arrestin Kinase References External links Proteins EC 2.7.11 Transferases Protein kinases