(E) Apoptosis was assayed in indicated HCT116 cells after treatment with doxorubicin (Doxo, 1 μg/ml), UV irradiation (5 min after 50 mJ/cm2) or transfected with BAX (1 μg) for 24 h. BAX, BCL2‐associated X protein; CCD, coiled‐coil domain; CHAPS, 3‐[(3‐cholamidopropyl)‐dimethylammonio]‐1‐propane sulphonate; GST, glutathione‐S‐transferase; IB, immunoblotting; IgG, immunoglobulin G; IP, immunoprecipitation; RIPA, radioimmunoprecipitation assay; SDS-PAGE, SDS-polyacrylamide gel electrophoresis; UV, ultraviolet; UVRAG, ultraviolet irradiation resistance associated gene. 