Phosphorylation and regulation of Akt/PKB by the rictor-mTOR complex

Science. 2005 Feb 18;307(5712):1098-101. doi: 10.1126/science.1106148.

Abstract

Deregulation of Akt/protein kinase B (PKB) is implicated in the pathogenesis of cancer and diabetes. Akt/PKB activation requires the phosphorylation of Thr308 in the activation loop by the phosphoinositide-dependent kinase 1 (PDK1) and Ser473 within the carboxyl-terminal hydrophobic motif by an unknown kinase. We show that in Drosophila and human cells the target of rapamycin (TOR) kinase and its associated protein rictor are necessary for Ser473 phosphorylation and that a reduction in rictor or mammalian TOR (mTOR) expression inhibited an Akt/PKB effector. The rictor-mTOR complex directly phosphorylated Akt/PKB on Ser473 in vitro and facilitated Thr308 phosphorylation by PDK1. Rictor-mTOR may serve as a drug target in tumors that have lost the expression of PTEN, a tumor suppressor that opposes Akt/PKB activation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3-Phosphoinositide-Dependent Protein Kinases
  • Adaptor Proteins, Signal Transducing
  • Animals
  • Carrier Proteins / metabolism*
  • Cell Line
  • Cell Line, Tumor
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster
  • Enzyme Activation
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Immunoprecipitation
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphorylation
  • Protein Kinases / metabolism*
  • Protein-Serine-Threonine Kinases / metabolism*
  • Proteins / metabolism
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-akt
  • RNA Interference
  • Rapamycin-Insensitive Companion of mTOR Protein
  • Regulatory-Associated Protein of mTOR
  • Serine / metabolism
  • TOR Serine-Threonine Kinases

Substances

  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • Drosophila Proteins
  • Proteins
  • Proto-Oncogene Proteins
  • RICTOR protein, human
  • RPTOR protein, human
  • Rapamycin-Insensitive Companion of mTOR Protein
  • Regulatory-Associated Protein of mTOR
  • rictor protein, Drosophila
  • Serine
  • Protein Kinases
  • Phosphatidylinositol 3-Kinases
  • target of rapamycin protein, Drosophila
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • 3-Phosphoinositide-Dependent Protein Kinases
  • AKT1 protein, human
  • Akt1 protein, Drosophila
  • PDPK1 protein, human
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt