Cdk phosphorylation of RUNX1 does not increase its interaction with the p300 coactivator. Cell lysates prepared from 293T cells transiently transfected with Flag-p300 and Myc-RUNX1, Myc-RUNX1(tripleA), or Myc-RUNX1(tripleD) were subjected to immunoprecipitation (IP) with rabbit Ig or rabbit anti-Flag followed by Western blotting (WB) with c-Myc tag monoclonal antibody. I indicates input and represents 5% of lysate used for immunoprecipitation. * indicates location of specific bands.