HDAC6 modulates Hsp90 chaperone activity and regulates activation of aryl hydrocarbon receptor signaling Academic Article uri icon


MeSH Major

  • HSP90 Heat-Shock Proteins
  • Histone Deacetylases
  • Receptors, Aryl Hydrocarbon
  • Signal Transduction


  • The aryl hydrocarbon receptor (AhR), a ligand-activated member of the basic helix-loop-helix family of transcription factors, binds with high affinity to polycyclic aromatic hydrocarbons (PAH) and the environmental toxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). Most of the biochemical, biological, and toxicological responses caused by exposure to PAHs and polychlorinated dioxins are mediated, at least in part, by the AhR. The AhR is a client protein of Hsp90, a molecular chaperone that can be reversibly acetylated with functional consequences. The main objective of this study was to determine whether modulating Hsp90 acetylation would affect ligand-mediated activation of AhR signaling. Trichostatin A and suberoylanilide hydroxamic acid, two broad spectrum HDAC inhibitors, blocked PAH and dioxin-mediated induction of CYP1A1 and CYP1B1 in cell lines derived from the human aerodigestive tract. Silencing HDAC6 or treatment with tubacin, a pharmacological inhibitor of HDAC6, also suppressed the induction of CYP1A1 and CYP1B1. Inhibiting HDAC6 led to hyperacetylation of Hsp90 and loss of complex formation with AhR, cochaperone p23, and XAP-2. Inactivation or silencing of HDAC6 also led to reduced binding of ligand to the AhR and decreased translocation of the AhR from cytosol to nucleus in response to ligand. Ligand-induced recruitment of the AhR to the CYP1A1 and CYP1B1 promoters was inhibited when HDAC6 was inactivated. Mutation analysis of Hsp90 Lys(294) shows that its acetylation status is a strong determinant of interactions with AhR and p23 in addition to ligand-mediated activation of AhR signaling. Collectively, these results show that HDAC6 activity regulates the acetylation of Hsp90, the ability of Hsp90 to chaperone the AhR, and the expression of AhR-dependent genes. Given the established link between activation of AhR signaling and xenobiotic metabolism, inhibitors of HDAC6 may alter drug or carcinogen metabolism.

publication date

  • March 20, 2009



  • Academic Article



  • eng

PubMed Central ID

  • PMC2658039

Digital Object Identifier (DOI)

  • 10.1074/jbc.M808999200

PubMed ID

  • 19158084

Additional Document Info

start page

  • 7436

end page

  • 45


  • 284


  • 12