A selective inhibitor of ALK5 (TGF- type I receptor). It has also been shown that this compound can replace Sox2 when reprogramming cells to iPS cells.
Ref: Gellibert, F., et al. (2004) Identification of 1, 5-naphthyridine derivatives as a novel series of potent and selective TGF-beta type I receptor inhibitors. J Med Chem 47: 4494-4506. Ichida, J.K., et al. (2009) A small-molecule inhibitor of Tgf- signaling replaces Sox2 in reprogramming by inducing Nanog. Cell Stem Cell 5: 491-503.