THE ROLE OF PRENYLATION IN G-PROTEIN ASSEMBLY AND FUNCTION

Heterotrimeric guanine nucleotide-binding regulatory proteins (G-prote ins) are vital components of numerous signal transduction pathways, in cluding sensory and hormonal response systems. G-proteins transduce si gnals from heptahelical transmembrane receptors to downstream effector s. The localization of a G-protein to the plasma membrane, as well as its interaction with the appropriate receptor and effector, are essent ial for its function. In addition, the association of a G-protein's su bunits to form its trimer is required for interaction with its recepto r. The G-protein gamma subunits (G(gamma)) are subject to a set of car boxyl-terminal processing events that include prenylation of a cystein e, proteolysis, and methylation. Recent advances which elucidate the c ontributions that the post-translational modifications of the G(gamma) subunit have on the assembly, membrane association, and function of t he G-protein trimer reveal that these modifications are required for i mportant protein-protein, in addition to membrane-protein, interaction s. Copyright (C) 1996 Elsevier Science Inc.