Keap1 facilitates p62-mediated ubiquitin aggregate clearance via autophagy

Weiliang Fan, Zaiming Tang, Dandan Chen, Diana Moughon, Xiaojun Ding, She Chen, Muyuan Zhu, Qing Zhong

Research output: Contribution to journalArticlepeer-review

198 Scopus citations

Abstract

The accumulation of ubiquitin-positive protein aggregates has been implicated in the pathogenesis of neurodegenerative diseases, heart disease and diabetes. Emerging evidence indicates that the autophagy lysosomal pathway plays a critical role in the clearance of ubiquitin aggregates, a process that is mediated by the ubiquitin binding protein p62. In addition to binding ubiquitin, p62 also interacts with LC3 and transports ubiquitin conjugates to autophagosomes for degradation. The exact regulatory mechanism of this process is still largely unknown. Here we report the identification of Keap1 as a binding partner for p62 and LC3. Keap1 inhibits Nrf2 by sequestering it in the cytosol and preventing its translocation to the nucleus and activation of genes involved in the oxidative stress response. In this study, we found that Keap1 interacts with p62 and LC3 in a stress-inducible manner, and that Keap1 colocalizes with LC3 and p62 in puromycin-induced ubiquitin aggregates. Moreover, p62 serves as a bridge between Keap1 and ubiquitin aggregates and autophagosomes. Finally, genetic ablation of Keap1 leads to the accumulation of ubiquitin aggregates, increased cytotoxicity of misfolded protein aggregates, and defective activation of autophagy. Therefore, this study assigns a novel positive role of Keap1 in upregulating p62-mediated autophagic clearance of ubiquitin aggregates.

Original languageEnglish (US)
Pages (from-to)614-621
Number of pages8
JournalAutophagy
Volume6
Issue number5
DOIs
StatePublished - Jul 1 2010

Keywords

  • Autophagosome
  • Autophagy
  • Keap1
  • LC3
  • Nrf2
  • Oxidative stress
  • Protein aggregates
  • Ubiquitin
  • p62

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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