Publication

A dynamic network model of mTOR signaling reveals TSC-independent mTORC2 regulation

Dalle Pezze, P., Sonntag, A. G., Thien, A., Prentzell, M. T., Gödel, M., Fischer, S., Neumann-Haefelin, E., Huber, T. B., Baumeister, R., Shanley, D. P. & Thedieck, K., 27-Mar-2012, In : Science signaling. 5, 217, p. ra25

Research output: Contribution to journalArticleAcademicpeer-review

  • Piero Dalle Pezze
  • Annika G Sonntag
  • Antje Thien
  • Mirja T Prentzell
  • Markus Gödel
  • Sven Fischer
  • Elke Neumann-Haefelin
  • Tobias B Huber
  • Ralf Baumeister
  • Daryl P Shanley
  • Kathrin Thedieck

The kinase mammalian target of rapamycin (mTOR) exists in two multiprotein complexes (mTORC1 and mTORC2) and is a central regulator of growth and metabolism. Insulin activation of mTORC1, mediated by phosphoinositide 3-kinase (PI3K), Akt, and the inhibitory tuberous sclerosis complex 1/2 (TSC1-TSC2), initiates a negative feedback loop that ultimately inhibits PI3K. We present a data-driven dynamic insulin-mTOR network model that integrates the entire core network and used this model to investigate the less well understood mechanisms by which insulin regulates mTORC2. By analyzing the effects of perturbations targeting several levels within the network in silico and experimentally, we found that, in contrast to current hypotheses, the TSC1-TSC2 complex was not a direct or indirect (acting through the negative feedback loop) regulator of mTORC2. Although mTORC2 activation required active PI3K, this was not affected by the negative feedback loop. Therefore, we propose an mTORC2 activation pathway through a PI3K variant that is insensitive to the negative feedback loop that regulates mTORC1. This putative pathway predicts that mTORC2 would be refractory to Akt, which inhibits TSC1-TSC2, and, indeed, we found that mTORC2 was insensitive to constitutive Akt activation in several cell types. Our results suggest that a previously unknown network structure connects mTORC2 to its upstream cues and clarifies which molecular connectors contribute to mTORC2 activation.

Original languageEnglish
Pages (from-to)ra25
JournalScience signaling
Volume5
Issue number217
Publication statusPublished - 27-Mar-2012

    Keywords

  • Adaptor Proteins, Signal Transducing, Animals, Carrier Proteins, Cell Line, Computer Simulation, Gene Knockdown Techniques, HeLa Cells, Humans, Immunoblotting, Immunoprecipitation, Insulin, Models, Biological, Multiprotein Complexes, Phosphatidylinositol 3-Kinases, Phosphorylation, Protein Binding, Ribosomal Protein S6 Kinases, 70-kDa, Signal Transduction, Software, TOR Serine-Threonine Kinases, Transcription Factors, Tumor Suppressor Proteins

ID: 13795772