(A) Pten+/+Baff+/+Cd19Cre and PtenL/LBaff+/+Cd19Cre B cells were left untreated, or were cultured in the presence of BAFF or anti-IgM F(ab′)2 fragments. Activation of non-canonical NF-κB was determined by western blotting with antibodies against p100/p52. Membranes were stripped and reprobed for actin as a loading control. (B) Western blots of protein lysates from freshly-isolated Pten+/+Baff+/+Cd19Cre, PtenL/LBaff+/+Cd19Cre, Pten+/+Baff−/−Cd19Cre, or PtenL/LBaff−/−Cd19Cre splenic B cells probed with anti-pAkt1 (S473), anti-GSK-3β (S9), anti-Mcl-1, or anti-Akt1 antibodies. (C) Pten+/+Cd19Cre and PtenL/LCd19Cre B cells were left untreated or were treated with BAFF. Lysates were generated and Mcl-1 was immunoprecipitated. Immunoprecipitates were resolved by SDS-PAGE and membranes probed with antibodies against Bim and Mcl-1.