E HEK293T cells were transfected with the Flag-CUEDC2 or Flag-CUEDC2△CUE (deletion of the CUE domain of CUEDC2), and treated with MG-132 (10 µM) for 6 hours before harvest. Cell lysates were immunoprecipitated (IP) with anti-Flag (M2). The immunoprecipitates were analyzed by western blot using an anti-GPX1 antibody. Whole-cell lysates (WCL) were analyzed by Western blots with anti-Flag or anti-GPX1 antibody to determine the protein of Flag-CUEDC2 and GPX1. v: vector. 