Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA

^aAuthor for correspondence

G Proteins provide signal transduction mechanisms to seven transmembrane receptors. Recent studies have indicated that the -subunits as well as the -subunits of these proteins regulate several critical signaling pathways involved in cell proliferation, differentiation and apoptosis. Of the 17 -subunits that have been cloned, at least ten of them have been shown to couple mitogenic signaling in fibroblast cells. Activating mutations in G_s, G_i2, and G₁₂ have been correlated with different types of tumors. In addition, the ability of the -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 - as well as the -subunits of G proteins in regulating cell proliferation.

G proteins; oncogene; signaling; ERK; JNK; Ras