Figure 5.

SOCS2 regulates Jak2-STAT3 binding and Jak2 kinase activity. (A) Lysates from control and SOCS2-overexpressing cells were immunoprecipitated with Jak2 antibodies, and immunoprecipitated complexes were resolved on SDS-PAGE. The indicated molecules were visualized using Western blot analysis. (B) Purified recombinant SOCS2 and Jak2 proteins were incubated at room temperature in the presence of 15 μCi γ³²-ATP and the exogenous substrate enolase for 30 minutes. Reactions were terminated with the addition of sample buffer, boiled for 5 minutes, and separated on an 8% SDS-PAGE. Radiolabeled proteins were detected by autoradiography.