FIG. 5.

MKP-1 mRNA induction by proinflammatory stimuli is dependent upon p38. HeLa cells were incubated for 10 min with different inhibitors as follows: no inhibitor (control) (−), 1 μM SB203580 (SB), 10 μM U0126 (U), 1 μM GF109203X (GF), and 0.5 μM protein kinase A inhibitor (PKI). Some cells were then incubated for 1 h in the presence of 100 nM dexamethasone (Dex lanes). Some cells were then stimulated with 20 ng of IL-1 per ml for 1 h (IL-1 lanes). MKP-1 mRNA was analyzed by Northern blotting. The 28S rRNA is shown as a loading control.