IFN-β and IL-6 influence the interaction of Shc proteins with Grb2. Extracts prepared from IL-6 and IFN-β stimulated U266 cells were used for either GST-fusion protein interaction studies (top three panels) or immunoprecipitation with anti-Shc antibodies (bottom panel). In all cases lysates were incubated with the specified fusion proteins or antibodies for 2 hours at 4°C and associated proteins detected by immunoblotting with either anti-Shc (in the case of Grb2 fusion protein interaction studies) or anti-Grb2 MoAbs (in the case of Shc immunoprecipitations).