FIGURE 6.

Combined hormone-induced tyrosine phosphorylation of c-Src in PC12 cells. A, representative Western blots of anti-phosphotyrosine immunoprecipitates depicting c-Src Tyr-418 autophosphorylation upon EGF, IGF, or NGF stimulation for 5, 10, and 30 min duration. Protein expression was controlled by assessing the presence of nonphosphorylated c-Src in an anti-Src immunoprecipitate from the same original cell lysate sample. The histograms in B depict means ± S.E. Shc tyrosine phosphorylation data from at least three independent experiments per histogram as demonstrated in A. EGF (blue bars), IGF (red bars), and NGF (green bars) indicate responses induced by individual ligand stimulation. Shaded mixed color bars indicate theoretical summation of individual responses compared with the actual resultant response induced by legend co-stimulation (black bars). IP, immunoprecipitation; IB, immunoblot; NS, no stimulation.