Regulation of cell proliferation by G proteins

Abstract

G Proteins provide signal transduction mechanisms to seven transmembrane receptors. Recent studies have indicated that the α-subunits as well as the βγ-subunits of these proteins regulate several critical signaling pathways involved in cell proliferation, differentiation and apoptosis. Of the 17 α-subunits that have been cloned, at least ten of them have been shown to couple mitogenic signaling in fibroblast cells. Activating mutations in Gα_s, Gα_i2, and Gα₁₂ have been correlated with different types of tumors. In addition, the ability of the βγ-subunits to activate mitogenic pathways in different cell-types has been defined. The present review briefly summarizes the diverse and novel signaling pathways regulated by the α- as well as the βγ-subunits of G proteins in regulating cell proliferation.