Dynamic adipocyte phosphoproteome reveals that Akt directly regulates mTORC2

Cell Metab. 2013 Jun 4;17(6):1009-20. doi: 10.1016/j.cmet.2013.04.010. Epub 2013 May 16.

Abstract

A major challenge of the post-genomics era is to define the connectivity of protein phosphorylation networks. Here, we quantitatively delineate the insulin signaling network in adipocytes by high-resolution mass spectrometry-based proteomics. These data reveal the complexity of intracellular protein phosphorylation. We identified 37,248 phosphorylation sites on 5,705 proteins in this single-cell type, with approximately 15% responding to insulin. We integrated these large-scale phosphoproteomics data using a machine learning approach to predict physiological substrates of several diverse insulin-regulated kinases. This led to the identification of an Akt substrate, SIN1, a core component of the mTORC2 complex. The phosphorylation of SIN1 by Akt was found to regulate mTORC2 activity in response to growth factors, revealing topological insights into the Akt/mTOR signaling network. The dynamic phosphoproteome described here contains numerous phosphorylation sites on proteins involved in diverse molecular functions and should serve as a useful functional resource for cell biologists.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Adipocytes / metabolism*
  • Animals
  • Carrier Proteins / metabolism*
  • Cell Line
  • Insulin / metabolism
  • Mass Spectrometry
  • Mechanistic Target of Rapamycin Complex 2
  • Mice
  • Multiprotein Complexes / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation
  • Proteome
  • Proteomics
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Signal Transduction
  • TOR Serine-Threonine Kinases / metabolism*

Substances

  • Carrier Proteins
  • Insulin
  • Multiprotein Complexes
  • Proteome
  • stress-activated protein kinase-interacting protein, mouse
  • Phosphatidylinositol 3-Kinases
  • TOR Serine-Threonine Kinases
  • Mechanistic Target of Rapamycin Complex 2
  • Proto-Oncogene Proteins c-akt