TGF-β RI Kinase Inhibitor III is a cell-permeable imidazolyl-pyridine compound that acts as a potent, ATP-competitive, reversible, and selective inhibitor of ACTR-IB (activin receptor-like kinase 4, IC50 = 129 nM), TGF β RI (activin receptor-like kinase 5, IC50 = 47 nM), and ACTR-IC (activin receptor-like kinase 7). TGF-β RI Kinase Inhibitor III inhibits p38 MAPKα only at much higher concentrations IC50 = 10.6 βM) and has little effect against ALK1/2/3/6 as well as a panel of 26 other kinases.
