G-Protein Coupled Receptors sense extracellular signals and activate different Guanine nucleotide binding proteins. Upon activation, the Guanine nucleotide-binding protein G(i) subunit alpha (GNAI) can directly bind to proto-oncogene tyrosine-protein kinase Src (SRC). When bound to active GNAI, SRC can autophosphorylate the 416-tyrosine residue. Upon autophosphorylation, SRC dissociates from GNAI and is subsequently activated. GNAI increases SRC enzymatic activity by decreasing Km and not affecting Vm. Physiologically, the SRC family have implications in cell growth and cancer.