CINPA1 disrupts interaction of CAR with coactivators and enhances corepressor binding. (A and B) Mammalian two-hybrid assays were set up in HEK293T cells transfected with expression plasmids encoding VP16AD-hCAR1 fusion protein, GAL4DBD-coregulator fusion proteins, and the reporter plasmid pG5luc . Cells were treated with DMSO (control), 5 µM CITCO, 5 µM CINPA1, 10 µM PK11195, or 1 µM CITCO + 5 µM CINPA1 for 24 hours before measurement of luciferase activities. Fold interaction represents pG5luc reporter activity normalized to the Renilla luciferase internal control. Data presented are the mean ± S.D. of at least three independent transfections. ***P < 0.001 compared with DMSO treatment within the same coregulator set. ns, not significant.