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 heter otrimeric G proteins can engage multiple signaling pathways leading to dive rse 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 inte racting with different effecters leading to engagement of distinct signalin g pathways. Regulation of different pathways in turn leads to different bio logical 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 activat ed in the process of transformation. Expression of activated G alpha subuni ts have been shown to cause transformation of cells, While activation of th e MAPK 1,2 pathway by various G alpha subunits has been reported for severa l years, recent studies show the activation and involvement of Src and Stat 3 pathways in G alphao and G alphai mediated transformation of cells. Recen t studies also suggest that both G alphai and G alphas may be able to inter act with and activate Src, The activation of Src and Stat3 by G proteins ha s also been demonstrated by Ligand-induced activation of G protein receptor s, 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 prot ein function.