Figure 7. PP2A-B56γ3 inhibits CDK2 activity.
CDK2 was immunoprecipitated from HeLa cells carrying vector only, B56γ3 overexpression or shB56γ3 by anti-CDK2 antibody. CDK2 kinase activities were assessed by using Histone H1 as substrate in the presence of [γ-32P]-ATP and kinase reactions were performed according to the procedure described under the “Materials and Methods”. Subsequently, reaction products were resolved by SDS-PAGE and analyzed by autoradiography. Relative CDK activities were quantified by densitometry and normalized with total CDK2 protein levels which were determined by immunoblotting. Representative immunoblotting data shown are from one representative experiment and quantified data of relative CDK activities shown are means ± S.D. of at least three experiments with similar results.