Role of phosphorylation of PP2Ac at Y307 in the SET/PP2A assembly. Freshly isolated CLL cells were cultured in the absence or presence of 50 µM pervanadate at different time points and subjected to 3 different analyses. (A) The samples were analyzed by western blot (Wb) analysis with anti-pY307-PP2Ac antibody, and the blots were reprobed with anti-PP2Ac antibody. (B) Whole B-cell lysates treated as described before were incubated with pAkt, obtained by immunoprecipitation from CLL cells, for 10 minutes at 37°C, and the samples were subsequently analyzed by Wb analysis with anti-pAkt and anti-Akt antibodies. (C) Each sample underwent immunoprecipitation with anti-PP2Ac antibody (left panel) or anti-SET antibody (right panel), and the immunocomplexes were analyzed by Wb analysis with anti-SET and anti-PP2Ac, respectively. Blots were then stripped and reprobed with the antibody applied for immunoprecipitations. The bar graph above the blot panels represents the values of a densitometric analysis (arbitrary units) of the anti-PP2Ac and anti-SET bands, expressed as ± SD. The pervanadate-treated samples compared with the untreated ones yielded statistically significant changes (*P < .01). Data are representative of experiments performed in triplicate on samples from 20 CLL patients.