Three related forms of the kinase Akt (1, 2, 3, also known as protein kinase B isoforms PKBα, β, γ) modulate cell proliferation, metabolism, and survival as well as angiogenesis. Akt inhibitor VIII is a potent allosteric inhibitor of Akt1 and Akt2 (IC50s = 58 and 210 nM, respectively) that less effectively blocks Akt3 activity (IC50 = 2.2 μM). It is a poor or ineffective inhibitor of a wide range of other serine-threonine kinases. Akt inhibitor VIII is cell permeable, blocking insulin regulation of forkhead box 01 activity at 1 μM in rat hepatoma cells.
