Effect of RWJ 67657 on phosphorylation of p38 MAPK and MAPKAPK-2. (a) Representative presentation of phosphorylation of p38 mitogen-activated protein kinase (MAPK) in monocyte-derived macrophages after stimulation with lipopolysaccharide (LPS) at various time points. Phosphorylation was measured by western blotting using specific antibodies to p38 MAPK and phospho-p38 MAPK. (b) Effect of RWJ 67657 on phosphorylation of the direct substrate of p38 MAPK, MAPKAPK-2 (MAPK-activating protein kinase-2), measured after 30 minutes of stimulation. DMSO = dimethyl sulfoxide.