D, E. HEK293T cells were transfected with plasmids encoding MYC-FOXP3, FLAG-USP44 (either wild type USP44, "wt" or the C282S mutant). These cells were subsequently treated with cycloheximide (CHX; 5μg/ml) for the indicated time points before harvested and cell lysis. FOXP3 levels and the relative turnover rate of this factor was determined by immunoblotting analysis with anti-MYC antibodies. 