Figure 3.

Ku70 disruption results in accumulation of ubiquitinated Mcl-1 and reduced Mcl-1 half-life. (a) Mcl-1 ubiquitination analyzed by anti-HA western blot following anti-Mcl-1 co-IP in H1299 cells expressing Ku70 shRNA, USP9X shRNA or control shRNA 48 h after transfection with HA-tagged ubiquitin (HA-Ub) constructs. (b) Mcl-1 ubiquitination analyzed as in (a) in WT or Ku70^−/− MEF cells transfected with HA-Ub constructs. (c) Mcl-1 expression in WT or Ku70^−/− MEF cells treated with 100 mg/ml cycloheximide 5 min before starting the indicated time course. Mcl-1 levels were quantified by ImageJ software to calculate the half-life