HDAC6 modulates Hsp90 chaperone activity and regulates activation of aryl hydrocarbon receptor signaling Journal Article
| Authors: | Kekatpure, V. D.; Dannenberg, A. J.; Subbaramaiah, K. |
| Article Title: | HDAC6 modulates Hsp90 chaperone activity and regulates activation of aryl hydrocarbon receptor signaling |
| Abstract: | 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 Lys294 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. |
| Journal Title: | Journal of Biological Chemistry |
| Volume: | 284 |
| Issue: | 12 |
| ISSN: | 0021-9258 |
| Publisher: | American Society for Biochemistry and Molecular Biology |
| Date Published: | 2009-03-20 |
| Start Page: | 7436 |
| End Page: | 7445 |
| Language: | English |
| DOI: | 10.1074/jbc.M808999200 |
| PUBMED: | 19158084 |
| PROVIDER: | scopus |
| PMCID: | PMC2658039 |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 8" - "Export Date: 30 November 2010" - "CODEN: JBCHA" - "Source: Scopus" |
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