IFN-γ–induced tyrosine phosphorylation of JAK1, JAK2, and STAT1 in LoVo and IGR-5. Parental LoVo cells (LoVo) or IFN-resistant cells (IGR-5) were stimulated with IFN-γ (1,000 IU/mL) for indicated periods (h) and lysed. The postnuclear supernatants were immunoprecipitated with anti-JAK1 (A) or anti-JAK2 (B). The immunoprecipitates were blotted with antiphosphotyrosine antibody (upper panels, PY), then the membrane was stripped and reprobed with anti-JAK1 (A) or anti-JAK2 (B) antibodies (lower panels). (C) Total cell extracts were also blotted with anti-phospho STAT1 (PY-STAT1) and anti-STAT1 (STAT1).