A cell-permeable bis-indolo (indirubin) compound that acts as a highly potent, selective, reversible, and ATP-competitive inhibitor of GSK-3α/β (IC50
= 5 nM). Its specificity has been tested against various Cdk's (IC50
= 83, 300, 320, and 10,000 nM for Cdk5/p25, Cdk2/A, Cdk1/B, and Cdk4/D1, respectively) as well as many other commonly studied kinases (IC50
≥ 10 µM), including MAP kinases, PKA, PKC isoforms, PKG, CK, and IRTK. Inhibition of GSK by BIO has been shown to result in the activation of Wnt-signaling pathway and sustained pluripotency in human and murine ESCs (embryonic stem cells). Reported to maintain self-renewal in human and mouse embryonic stem cells. Also induces the differentiation of neonatal cardiomyocytes. A 10 mM (500 µg/140 µl) solution of GSK-3 Inhibitor IX (Cat. No. 361552
) in DMSO is also available.