SB 431542

SB-431542 is a potent and selective inhibitor of the TGF-β1 receptor ALK5 (IC₅₀ = 94 nM). It is a less potent antagonist of ALK4 (IC₅₀ = 140 nM) and ALK7. It does not affect the BMP receptors ALK2, ALK3, ALK6, or a panel of other kinases tested. SB-431542 specifically blocks Smad signaling, reducing gene expression relevant to fibrosis and cancer. Through its effects on ALK/Smad signaling, SB-431542 suppresses renewal in embryonic and induced pluripotent stem cells and promotes their differentiation.

ChEBI: A member of the class of benzamides that is 4-(imidazol-2-yl)benzamide carrying additional 1,3-benzodioxol-5-yl and pyridin-2-yl substituents at positions 4 and 5 respectively on the imidazole ring.

A cell-permeable triarylimidazole compound that is shown to effectively inhibit cellular Smad2 phosphorylation (>90% inhibition by 10 μM inhibitor) upon vector-mediated expression of constitutively active ALK4, ALK5, or ALK7 in NIH 3T3 cells, while exhibiting little effect against Smad1 phosphorylation by other members of type I receptors for TGF-β in NIH 3T3 cultures expressing active ALK1, 2, 3, or 6. When tested directly in cell-free kinase assays, SB431542 is demonstrated to potently inhibit the activity of ALK4 and ALK5 (IC₅₀ = 140 nM and 94 nM, respectively) with no or much reduced potency toward a panel of 24 other kinases (IC₅₀ ≥10 μM in the presence of 10 μM ATP), including ALK2 and ALK6. Reported to improve the efficiency of 4-TF-induced human iPSCs generation from fibroblast cultures by >200-fold when used together with PD0325901 (Cat. No. 444966) and Thiazovivin (Cat. No. 420220).

Potent and selective inhibitor of the transforming growth factor- β (TGF- β ) type I receptor activin receptor-like kinase ALK5 (IC 50 = 94 nM), and its relatives ALK4 and ALK7. Suppresses TGF- β -induced proliferation of human osteosarcoma cells. Stimulates proliferation, differentiation and sheet formation of ESC-derived endothelial cells.