FIG. 6.

Time courses of p38 activation and MKP-1 expression in the absence or presence of dexamethasone. HeLa cells were left untreated or treated with IL-1 (20 ng/ml) alone or with IL-1 (20 ng/ml) and dexamethasone (Dex) (1 μM), and lysates were prepared after the times indicated (15 min [15′]). (A) MKP-1 was immunoprecipitated from lysate (1.5 mg) and subjected to Western blotting. The band below MKP-1 is the light chain of the immunoprecipitating antibody. (B) Lysate (50 μg) was subjected to Western blotting using an antibody against p38α. (C) MAPK p38 was immunoprecipitated from lysate (500 μg) and used in immune complex kinase assays with recombinant MAPKAPK2 (MK2) as the substrate. (D) Quantitation of the data represented in panel C. The results shown are representative of at least two independent experiments.