HSF1 Critically Attunes Proteotoxic Stress Sensing by mTORC1 to Combat Stress and Promote Growth

Nat Cell Biol. 2016 May;18(5):527-39. doi: 10.1038/ncb3335. Epub 2016 Apr 4.


To cope with proteotoxic stress, cells attenuate protein synthesis. However, the precise mechanisms underlying this fundamental adaptation remain poorly defined. Here we report that mTORC1 acts as an immediate cellular sensor of proteotoxic stress. Surprisingly, the multifaceted stress-responsive kinase JNK constitutively associates with mTORC1 under normal growth conditions. On activation by proteotoxic stress, JNK phosphorylates both RAPTOR at S863 and mTOR at S567, causing partial disintegration of mTORC1 and subsequent translation inhibition. Importantly, HSF1, the central player in the proteotoxic stress response (PSR), preserves mTORC1 integrity and function by inactivating JNK, independently of its canonical transcriptional action. Thereby, HSF1 translationally augments the PSR. Beyond promoting stress resistance, this intricate HSF1-JNK-mTORC1 interplay, strikingly, regulates cell, organ and body sizes. Thus, these results illuminate a unifying mechanism that controls stress adaptation and growth.

MeSH terms

  • Animals
  • Body Size / drug effects
  • Cell Proliferation / drug effects
  • Cell Size / drug effects
  • DNA-Binding Proteins / metabolism*
  • Enzyme Activation / drug effects
  • HEK293 Cells
  • HeLa Cells
  • Heat Shock Transcription Factors
  • Heat-Shock Response* / drug effects
  • Humans
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Liver / cytology
  • Liver / drug effects
  • Liver / growth & development
  • MAP Kinase Signaling System / drug effects
  • Mechanistic Target of Rapamycin Complex 1
  • Mice
  • Multiprotein Complexes / metabolism*
  • Organ Size / drug effects
  • Phosphorylation / drug effects
  • Protein Biosynthesis / drug effects
  • Proteins / toxicity*
  • Stress, Physiological / drug effects*
  • TOR Serine-Threonine Kinases / metabolism*
  • Transcription Factors / metabolism*
  • Transcription, Genetic / drug effects


  • DNA-Binding Proteins
  • HSF1 protein, human
  • Heat Shock Transcription Factors
  • Hsf1 protein, mouse
  • Multiprotein Complexes
  • Proteins
  • Transcription Factors
  • TOR Serine-Threonine Kinases
  • Mechanistic Target of Rapamycin Complex 1
  • JNK Mitogen-Activated Protein Kinases