Selective inhibitor of p38 mitogen-activated protein kinase (IC50 values are 50 and 500 nM for SAPK2a/p38 and SAPK2b/p38β2 respectively). Displays 100-500-fold selectivity over LCK, GSK-3β and PKBα. Shown to inhibit interleukin-2-induced T-cell proliferation, cyclooxygenase-1 and -2, and thromboxane synthase. Enhances clonal growth of skin epithelial progenitor cells; stimulates neural stem cell (NSC) proliferation. Part of the MAPK Cascade Inhibitor Tocriset™ and MAPK Inhibitor Tocriset™. Water-soluble salt SB 203580 hydrochloride (Cat. No. 1402) also available.