IL-4–induced signaling in osteoclasts. The indicated cells were treated with rmIL-4 (10 ng/mL) or insulin, as indicated for 10 minutes. Lysates were immunoprecipitated with anti-STAT6 or anti–IRS-2 antibody, run on a 4% polyacrylamide gel and probed first with antiphosphotyrosine antibody. Membranes were stripped and reprobed with anti-STAT6 or anti–IRS-2 antibody. (A) Analysis of STAT6 tyrosine phosphorylation and protein level. (B) IRS-2 tyrosine phosphorylation and protein level. (C) IRS-2 phosphorylation on mature osteoclasts in response to insulin.