Deletion of the ubiquitin ligase CHIP leads to the accumulation, but not the aggregation, of both endogenous phospho- and caspase-3-cleaved tau species

Chad A. Dickey, Mei Yue, Wen Lang Lin, Dennis W. Dickson, Judith H. Dunmore, Wing C. Lee, Cynthia Zehr, Gemma West, Songsong Cao, Amber M.K. Clark, Guy A. Caldwell, Kim A. Caldwell, Christopher Eckman, Cam Patterson, Michael Hutton, Leonard Petrucelli

Research output: Contribution to journalArticlepeer-review

191 Scopus citations


Accumulation of the microtubule-associated protein tau into neurofibrillary lesions is a pathological consequence of several neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease. Hereditary mutations in the MAPT gene were shown to promote the formation of structurally distinct tau aggregates in patients that had a parkinsonian-like clinical presentation. Whether tau aggregates themselves or the soluble intermediate species that precede their aggregation are neurotoxic entities in these disorders has yet to be resolved; however, recent in vivo evidence supports the latter. We hypothesized that depletion of CHIP, a tau ubiquitin ligase, would lead to an increase in abnormal tau. Here, we show that deletion of CHIP in mice leads to the accumulation of non-aggregated, ubiquitin-negative, hyperphosphorylated tau species. CHIP-/- mice also have increased neuronal caspase-3 levels and activity, as well as caspase-cleaved tau immunoreactivity. Overexpression of mutant (P301L) human tau in CHIP-/- mice is insufficient to promote either argyrophilic or "pre-tangle" structures, despite marked phospho-tau accumulation throughout the brain. These observations are supported in postdevelopmental studies using RNA interference for CHIP (chn-1) in Caenorhabditis elegans and cell culture systems. Our results demonstrate that CHIP is a primary component in the ubiquitin-dependent degradation of tau. We also show that hyperphosphorylation and caspase-3 cleavage of tau both occur before aggregate formation. Based on these findings, we propose that polyubiquitination of tau by CHIP may facilitate the formation of insoluble filamentous tau lesions.

Original languageEnglish (US)
Pages (from-to)6985-6996
Number of pages12
JournalJournal of Neuroscience
Issue number26
StatePublished - 2006


  • Alzheimer's disease
  • CHIP
  • Neuronal cell death
  • Parkinson's disease
  • Proteasome degradation
  • Synuclein
  • Ubiquitination

ASJC Scopus subject areas

  • Neuroscience(all)


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