Effects of combined MEK inhibition and ATO treatment on Ser112 Bad phosphorylation and Bad protein levels in AML blasts. For the analysis of Bad phosphorylation, lysates were immunoprecipitated with rabbit polyclonal anti-Bad or with a control antibody, and the immunoprecipitated samples were subjected to 15% sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) followed by Western blot analysis with the anti–phospho-Ser112-Bad antibody. Filters were then stripped and reprobed with the anti-Bad antibody.