SB-505124 is a selective inhibitor of transforming growth factor-beta type I receptors ALK4, ALK5, and ALK7

Clinically, there is a great need for small molecule inhibitors that could control pathogenic effects of transforming growth factor (TGF-) and/or modulate effects of TGF- in normal responses. Inhibition of TGF- signaling would be predicted to enhance re-epithelialization of cutaneous wounds and reduce scarring fibrosis. Selective small molecule inhibitors of the TGF- sig-naling pathway developed for therapeutics will also be powerful tools in experimentally dissecting this complex pathway, espe-cially its cross-talk with other signaling pathways. In this study, we characterized 2-(5-benzo[1,3]dioxol-5-yl-2-tert-butyl-3H-imidazol-4-yl)-6-methylpyridine hydrochloride (SB-505124), a member of a new class of small molecule inhibitors related to imidazole inhibitors of p38, which inhibit the TGF- type I receptor serine/threonine kinase known as activin receptor-lik