SB-431542 (hydrate)

SB-431542 is a potent and selective inhibitor of the TGF-?1 receptor ALK5 (IC50 = 94 nM){16928}. It is a less potent antagonist of ALK4 (IC50 = 140 nM){16992} and ALK7.{16927} It does not affect the BMP receptors ALK2, ALK3, ALK6, or a panel of other kinases tested.{16927} SB-431542 specifically blocks Smad signaling, reducing gene expression relevant to fibrosis and cancer.{16927} Through its effects on ALK/Smad signaling, SB-431542 suppresses renewal in embryonic and induced pluripotent stem cells and promotes their differentiation.{17335,17336}