mTORC2 is required for rit-mediated oxidative stress resistance

PLoS One. 2014 Dec 22;9(12):e115602. doi: 10.1371/journal.pone.0115602. eCollection 2014.

Abstract

Rit, a member of the Ras family of GTPases, has been shown to promote cell survival in response to oxidative stress, in part by directing an evolutionarily conserved p38 MAPK-Akt survival cascade. Aberrant Rit signaling has recently been implicated as a driver mutation in human cancer, adding importance to the characterization of critical Rit effector pathways. However, the mechanism by which Rit-p38 signaling regulated Akt activity was unknown. Here, we identify mTORC2 as a critical downstream mediator of Rit-dependent survival signaling in response to reactive oxygen species (ROS) stress. Rit interacts with Sin1 (MAPKAP1), and Rit loss compromises ROS-dependent mTORC2 complex activation, blunting mTORC2-mediated phosphorylation of Akt kinase. Taken together, our findings demonstrate that the p38/mTORC2/Akt signaling cascade mediates Rit-dependent oxidative stress survival. Inhibition of this previously unrecognized cascade should be explored as a potential therapy of Rit-dependent malignancies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • Apoptosis
  • Blotting, Western
  • Cell Proliferation
  • Cells, Cultured
  • Embryo, Mammalian / cytology
  • Embryo, Mammalian / metabolism
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • HeLa Cells
  • Humans
  • Immunoprecipitation
  • Mechanistic Target of Rapamycin Complex 2
  • Mice
  • Multiprotein Complexes / metabolism*
  • Oxidative Stress*
  • Phosphorylation
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Reactive Oxygen Species / metabolism*
  • Signal Transduction
  • TOR Serine-Threonine Kinases / metabolism*
  • p38 Mitogen-Activated Protein Kinases / metabolism*
  • ras Proteins / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • MAPKAP1 protein, human
  • Multiprotein Complexes
  • Reactive Oxygen Species
  • Mechanistic Target of Rapamycin Complex 2
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases
  • p38 Mitogen-Activated Protein Kinases
  • RIT1 protein, human
  • ras Proteins