(A) Crkl and STAT5 immunoprecipitation was inhibited by the Crkl immunizing peptide. (Upper and lower panels) Crkl immunoprecipitation was performed as in Fig 3A and C, except that immunoprecipitation was performed in the presence of the Jak2 (control; left 2 lanes) or the Crkl immunizing peptides (right 2 lanes). (B) STAT5 was not immunoprecipitated by Crkl antisera after denaturing of Crkl immunoprecipitates. The left two lanes are same as in (A; 1st IP). After denaturing of Crkl immunoprecipitates and dilution into lysis buffer containing 0.5% SDS and 1% Triton X-100, Crkl was again immunoprecipitated (2nd IP; the right 2 lanes). Crkl and STAT5 were detected as in Fig 2A and C. (C) Crkl and STAT5 coimmunoprecipitation was inhibited by phenyl phosphate (20 mmol/L). (Upper and lower panels) Crkl immunoprecipitation was performed as in Fig 3A and C, except that immunoprecipitation was performed in the presence (right 2 lanes) or absence (left 2 lanes) of phenyl phosphate (20 mmol/L).