FIG. 3.

IL-6 induces SOCS3 phosphorylation resulting in an association with p120 RasGAP. IL-6KO dermal fibroblasts were cultured as described and treated with the indicated concentrations of rmIL-6 for up to 30 min. Cells were lysed and 100 μg of total protein per sample was immunoprecipitated with anti-SOCS3 antibody. SDS-PAGE gels were transferred to nitrocellulose membranes and blotted with anti-phospho-tyrosine (A), anti-p120 RasGap (B, upper panel), or anti-SOCS3 (B, lower panel). Expression of SOCS3 mRNA was evaluated after IL-6 treatment in fibroblasts (C) as determined by QPCR (n=4). SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; QPCR, quantitative polymerase chain reaction.