Immunoblot Analysis: HeLa cells were cultured under serum-free conditions for 24h and subsequently stimulated with 10 ng/ml EGF. Cells were lysed with RIPA buffer and shc immunoprecipitated with polyclonal anti-shc (Transduction Labs). Immunoprecipitates were separated by SDS-PAGE. Immunoblots were developed using mab shc/p66-6E10 at 1 ug/ml.