Tyrosine phosphorylation of Jak kinases, Stat-2, and the insulin receptor in THP-1 cells. Antiphosphotyrosine immunoblots are shown. (A) Cells were stimulated with IFN-α for 5 minutes as indicated, and cell lysates were immunoprecipitated with the indicated antibodies. (B) Cells were stimulated with IFN-α for 15 minutes as indicated, and cell lysates were immunoprecipitated with an antibody against Jak-1. (C) Cells were stimulated with IFN-α for 15 minutes as indicated, and cell lysates were immunoprecipitated with an antibody against Stat-2. (D) Cells were stimulated with insulin for 15 minutes as indicated, and cell lysates were immunoprecipitated with an antibody against the insulin receptor.