SB-431542

SB-431542 is a potent, specific TGF-β type I receptor (ALK5) inhibitor with IC50 of 94 nM; also substantially inhibits ALK4 and 7, but not other ALKs; efficiently inhibits the ability of activated ALK4, ALK5, and ALK7 to phosphorylate Smad2; a selective inhibitor of endogenous activin and TGF-beta signaling but has no effect on BMP signaling, and has no effect on components of the ERK, JNK, or p38 MAP kinase pathways.(In Vitro):SB-431542 can inhibit the activity for ALK4, ALK5 and ALK7 with IC50 values of 1 μM, 0.75 μM and 2 μM, respectively.SB-431542 (0- 10 μM; 24 h) inhibits ALK5 and also the activin type I receptor ALK4 and the nodal type I receptor ALK7, which are very highly related to ALK5 in their kinase domains.SB-431542 (0.1, 0.5, 1, 5, or 10 μM; 30 min) efficiently inhibits Smad phosphorylation induced by TGF-β and activin but not BMP4.SB-431542 (0-10 μM) inhibits TGF-beta-induced transcription, gene expression, apoptosis, and growth suppression.(In Vivo):SB-431542 (subconjunctival; 0.5 and 2 mM; on days 1, 2, 3, and 7) inhibits scar formation after glaucoma filtration surgery in New Zealand rabbits.