Heat Shock Factor 1 Is a Substrate for p38 Mitogen-Activated Protein Kinases

Mol Cell Biol. 2016 Aug 26;36(18):2403-17. doi: 10.1128/MCB.00292-16. Print 2016 Sep 15.


Heat shock factor 1 (HSF1) monitors the structural integrity of the proteome. Phosphorylation at S326 is a hallmark for HSF1 activation, but the identity of the kinase(s) phosphorylating this site has remained elusive. We show here that the dietary agent phenethyl isothiocyanate (PEITC) inhibits heat shock protein 90 (Hsp90), the main negative regulator of HSF1; activates p38 mitogen-activated protein kinase (MAPK); and increases S326 phosphorylation, trimerization, and nuclear translocation of HSF1, and the transcription of a luciferase reporter, as well as the endogenous prototypic HSF1 target Hsp70. In vitro, all members of the p38 MAPK family rapidly and stoichiometrically catalyze the S326 phosphorylation. The use of stable knockdown cell lines and inhibitors indicated that among the p38 MAPKs, p38γ is the principal isoform responsible for the phosphorylation of HSF1 at S326 in cells. A protease-mass spectrometry approach confirmed S326 phosphorylation and unexpectedly revealed that p38 MAPK also catalyzes the phosphorylation of HSF1 at S303/307, previously known repressive posttranslational modifications. Thus, we have identified p38 MAPKs as highly efficient catalysts for the phosphorylation of HSF1. Furthermore, our findings suggest that the magnitude and persistence of activation of p38 MAPK are important determinants of the extent and duration of the heat shock response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics*
  • HSP70 Heat-Shock Proteins / metabolism*
  • HSP90 Heat-Shock Proteins / antagonists & inhibitors
  • HeLa Cells
  • Heat Shock Transcription Factors
  • Humans
  • Isothiocyanates / pharmacology
  • Mice
  • Mouse Embryonic Stem Cells / cytology
  • Mouse Embryonic Stem Cells / metabolism
  • Phosphorylation
  • Protein Multimerization
  • Protein Transport
  • Serine / metabolism*
  • Transcription Factors / chemistry
  • Transcription Factors / genetics*
  • Transcription, Genetic*
  • p38 Mitogen-Activated Protein Kinases / metabolism*


  • DNA-Binding Proteins
  • HSF1 protein, human
  • HSP70 Heat-Shock Proteins
  • HSP90 Heat-Shock Proteins
  • Heat Shock Transcription Factors
  • Isothiocyanates
  • Transcription Factors
  • Serine
  • phenethyl isothiocyanate
  • p38 Mitogen-Activated Protein Kinases