ALK5 inhibitor II is a cell permeable, selective inhibitor of the TGF-β type 1 activin like kinase receptor ALK5 (IC50s = 4, 18, and 23 nM for ALK5 autophosphorylation, TGF-β cellular assay, and ALK5 binding in HepG2 cells, respectively). This inhibitor demonstrated less potent activity (IC50s > 16 μM) when tested against a panel of 9 related kinases, including p38 MAPK and GSK3. At 25 μM, this compound has been used to induce stem cell pluripotency by replacing the reprogramming transcription factor Sox2 via inhibition of the TGF-β signaling pathway and induction of Nanog transcription.
