Akt regulates growth by phosphorylating and inhibiting the TSC1-TSC2 complex in drosophila. A schematic representation of genetic epistasis illustrates that stimulation of Akt activity, by activation of IR, PI(3)K, or loss of PTEN, results in TSC2 phosphorylation. This event inactivates TSC1–TSC2 complex. The inactivation results in increased cell growth, mediated by downstream inhibition of mTOR and activation of S6K.