G protein coupled receptor signaling through the Src and Stat3 pathway: role in proliferation and transformation

Extracellular signals when routed through signaling pathways that use heterotrimeric G proteins can engage multiple signaling pathways leading to diverse biological consequences, One locus at which signal sorting occurs is at the level of G proteins, G protein a-subunits appear to be capable of interacting with different effecters leading to engagement of distinct signaling pathways. Regulation of different pathways in turn leads to different biological outcomes, The process of neoplastic transformation is controlled to a large extent through the activation and inhibition of signaling pathways, Signaling pathways such as the Ras-MAPK, v-Src-Stat3 pathways are activated in the process of transformation. Expression of activated G alpha subunits have been shown to cause transformation of cells, While activation of the MAPK 1,2 pathway by various G alpha subunits has been reported for several years, recent studies show the activation and involvement of Src and Stat3 pathways in G alphao and G alphai mediated transformation of cells. Recent studies also suggest that both G alphai and G alphas may be able to interact with and activate Src, The activation of Src and Stat3 by G proteins has also been demonstrated by Ligand-induced activation of G protein receptors, So increasingly it is becoming clear that the Src and Stat3 pathways are potential effecters for G proteins and that they may play a role in G protein function.