Vanderbeld, B. and Kelly, G.M. (2000) New thoughts on the bg subunit in G protein signal transduction. Biochemistry and cell biology = Biochimie et biologie cellulaire. 78(5):537-550.
Heterotrimeric G proteins are involved in numerous biological processes, where they mediate signal transduction from agonist-bound G-protein-coupled receptors to a variety of intracellular effector molecules and ion channels. G proteins consist of two signaling moieties: a GTP-bound alpha subunit and a betagamma heterodimer. The betagamma dimer, recently credited as a significant modulator of G-protein-mediated cellular responses, is postulated to be a major determinant of signaling fidelity between G-protein-coupled receptors and downstream effectors. In this review we have focused on the role of betagamma signaling and have included examples to demonstrate the heterogeneity in the heterodimer composition and its implications in signaling fidelity. We also present an overview of some of the effectors regulated by betagamma and draw attention to the fact that, although G proteins and their associated receptors play an instrumental role in development, there is rather limited information on betagamma signaling in embryogenesis.