KEAP1 and lung carcinoma: To alternatively assess if the K39 residue altered the expression of KEAP1, we constructed human H1299 lung carcinoma cells with knockdown of the endogenous KEAP1 by expression of a short-hairpin RNA, then introduced constructs to re-express either the WT or KEAP1-K39R proteins (coded H1299-shKEAP1-WT or -K39R, respectively).