Figure 3. Activation of p38 MAPK by TNF-{alpha}. (Panel A) Time course (min) of TNF-{alpha} stimulation (20 ng/mL). (Panel B) Inhibition of p38 MAPK phosphorylation by SB203580 HCl. Cells serum-starved overnight, pre-incubated with SB203580HCl (10 µM) for 1 hr, followed by TNF-{alpha} stimulation (20 ng/mL) for 5 min.