Published December 28, 2009 | Version Supplemental Material + Published
Journal Article Open

IKK phosphorylates Huntingtin and targets it for degradation by the proteasome and lysosome

  • 1. ROR icon University of California, Irvine
  • 2. ROR icon Duke University
  • 3. ROR icon California Institute of Technology
  • 4. ROR icon Albert Einstein College of Medicine
  • 5. ROR icon Bellvitge University Hospital
  • 6. ROR icon University of Navarra
  • 7. ROR icon University of British Columbia
  • 8. ROR icon University of Virginia
  • 9. ROR icon Gladstone Institutes
  • 10. ROR icon University of California, San Francisco
  • 11. ROR icon King's College London

Abstract

Expansion of the polyglutamine repeat within the protein Huntingtin (Htt) causes Huntington's disease, a neurodegenerative disease associated with aging and the accumulation of mutant Htt in diseased neurons. Understanding the mechanisms that influence Htt cellular degradation may target treatments designed to activate mutant Htt clearance pathways. We find that Htt is phosphorylated by the inflammatory kinase IKK, enhancing its normal clearance by the proteasome and lysosome. Phosphorylation of Htt regulates additional post-translational modifications, including Htt ubiquitination, SUMOylation, and acetylation, and increases Htt nuclear localization, cleavage, and clearance mediated by lysosomal-associated membrane protein 2A and Hsc70. We propose that IKK activates mutant Htt clearance until an age-related loss of proteasome/lysosome function promotes accumulation of toxic post-translationally modified mutant Htt. Thus, IKK activation may modulate mutant Htt neurotoxicity depending on the cell's ability to degrade the modified species.

Additional Information

© 2009 Thompson et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.jcb.org/misc/terms.shtml). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/). Submitted: 10 September 2009; accepted: 20 November 2009. This paper is dedicated to the memory of Dr. Charles H. Sawyer, whose example was its constant inspiration. We thank Drs. David Housman, Matthew Blurton-Jones, Masashi Kitazawa, Peter Kaiser, Alex Osmand, Christian Landes, Bin Liu, and Daniel Keys for insightful discussion; Denise Dunn and Emily Mitchell for technical assistance; and Anne Dejean, Dirk Bohmann, Paul Muchowski, Harm Kampinga, Peter Kaiser, Christian Tagwerker, Cam Patterson, Heidi Rommelaere, Alex Kazantsev, Robert Friedlander, Erich Wanker, and Marian DiFiglia for their generous gifts of reagents for these experiments. This work was supported by the Hereditary Disease Foundation (J.S. Steffan, L.M. Thompson, J.L. Marsh, D.C. Lo, and P.H. Patterson); the Fox Family Foundation (J.S. Steffan and L.M. Thompson); the High Q Foundation (J.S. Steffan, L.M. Thompson, J.L. Marsh, and D.C. Lo); the Huntington's Disease Society of America Coalition for the Cure (L.M. Thompson); the Taube-Koret Center for Huntington's Disease Research (S. Finkbeiner); and National Institutes of Health awards NS52789 (L.M. Thompson and J.L. Marsh), HD36081 (J.L. Marsh), NS045283 (J.L. Marsh and L.M. Thompson), NS043466 (S.O. Zeitlin), GM74830 (L. Huang), 2R01NS039074 (S. Finkbeiner), 2R01NS045191 (S. Finkbeiner), 2P01AG022074 (S. Finkbeiner), P01AG031782 (A.M. Cuervo) and NS055298 (P.H. Patterson), and T32GM0731130 (C.T. Aiken).

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Additional details

Identifiers

PMCID
PMC2806289
Eprint ID
17302
Resolver ID
CaltechAUTHORS:20100125-115224074

Funding

Hereditary Disease Foundation
Fox Family Foundation
High Q Foundation
Huntington's Disease Society of America Coalition for the Cure
Taube-Koret Center for Huntington's Disease Research
NIH
NS52789
NIH
HD36081
NIH
NS045283
NIH
NS043466
NIH
GM74830
NIH
2R01NS039074
NIH
2R01NS045191
NIH
2P01AG022074
NIH
P01AG031782
NIH
NS055298
NIH
T32GM0731130

Dates

Created
2010-01-29
Created from EPrint's datestamp field
Updated
2021-11-08
Created from EPrint's last_modified field