B. Endogenous co-IP of USP44 and FOXP3 in murine iTregs. iTregs were generated as in Fig. 1 from naïve CD4+ T cells FACS isolated from pooled suspensions of the lymph node and spleen cells of wild type C57BL/6 mice (n=2-3/experiment). iTregs were lysed and key proteins were immunoprecipitated using either anti-USP44 (right panel) or anti-FOXP3 (left panel) antibody. Proteins pulled-down in this experiment were then resolved and analyzed by immunoblot using anti-FOXP3 or anti-USP44 antibodies. 