Guanine nucleotide-binding proteins (G proteins) are involved as a modulator or transducer in various transmembrane signaling systems. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction. G proteins are composed of 3 units, alpha, beta and gamma. Interacts with beta-1 and beta-3, but not with beta-2. Abundantly expressed in all tissues tested except for brain. Belongs to the G protein gamma family.