Influence of MRS2481 on TNFα-induced IκBα degradation in HeLa cells by MRS2481. (a) HeLa cells were pretreated with MRS2481 (5 μM) for 0, 1, 3, or 6 h, and then treated with 2 ng/ml TNFα for 15 min. Reaction mixtures were then subjected to polyacrylamide gel electrophoresis, blotted onto nitrocellulose, and probed with anti-IκBa antibody. (b) HeLa cells were pretreated with the less potent analogue MRS2485 (50 μM) for 0, 1, 3, or 6 h, and then treated with 2 ng/ml TNFα for 15 min. Reaction mixtures were then subjected to polyacrylamide gel electrophoresis, blotted onto nitrocellulose, and probed with anti-IκBα antibody.