Highlights • In healthy tissue, IRS signaling and negative feedback set PI3K pathway activity • Loss of PTEN leads to the adaptor PLEKHS1 becoming the main driver of PI3Ks • The switch results in part from negative feedback suppressing IRS activation of PI3Ks • PLEKHS1 evades negative feedback and is YXXM-phosphorylated by a PIP3-dependent mechanism Summary The PIP3/PI3K network is a central regulator of metabolism and is frequently activated in cancer, commonly by loss of the PIP3/PI(3,4)P2...