CDK-immune complex formation during terminal erythroid differentiation.

Whole cell lysates from FVA erythroblasts cultured with EPO for 0, 24, or 48 hours were immunoprecipitated with anti-cdk2 (A), -cdk4 (B), or -cdk6 (C) in the absence (−) or presence (+) of relevant blocking peptide. FVA erythroblasts were cultured with EPO for 6 hours in the presence of ActD and immunoprecipitated with anti-cdk2 or -cdk4 (D) or -cdk6 (C) in the absence (−) or presence (+) of relevant blocking peptide. Immune complexes were electrophoretically separated in 12% polyacrylamide gels and transferred to PVDF membranes. Western blot analysis was performed with antibodies to cdk2, cdk4, cdk6, p27, or p21.