The peroxisomal AAA ATPase complex prevents pexophagy and development of peroxisome biogenesis disorders

Kelsey B. Law, Dana Bronte-Tinkew, Erminia Di Pietro, Ann Snowden, Richard O. Jones, Ann Moser, John H. Brumell, Nancy Braverman, Peter K. Kim

Research output: Contribution to journalArticlepeer-review

Abstract

Peroxisome biogenesis disorders (PBDs) are metabolic disorders caused by the loss of peroxisomes. The majority of PBDs result from mutation in one of 3 genes that encode for the peroxisomal AAA ATPase complex (AAA-complex) required for cycling PEX5 for peroxisomal matrix protein import. Mutations in these genes are thought to result in a defect in peroxisome assembly by preventing the import of matrix proteins. However, we show here that loss of the AAA-complex does not prevent matrix protein import, but instead causes an upregulation of peroxisome degradation by macroautophagy, or pexophagy. The loss of AAA-complex function in cells results in the accumulation of ubiquitinated PEX5 on the peroxisomal membrane that signals pexophagy. Inhibiting autophagy by genetic or pharmacological approaches rescues peroxisome number, protein import and function. Our findings suggest that the peroxisomal AAA-complex is required for peroxisome quality control, whereas its absence results in the selective degradation of the peroxisome. Thus the loss of peroxisomes in PBD patients with mutations in their peroxisomal AAA-complex is a result of increased pexophagy. Our study also provides a framework for the development of novel therapeutic treatments for PBDs.

Original languageEnglish (US)
Pages (from-to)868-884
Number of pages17
JournalAutophagy
Volume13
Issue number5
DOIs
StatePublished - May 4 2017

Keywords

  • AAA ATPase complex
  • PEX1
  • PEX26
  • PEX5
  • Zellweger spectrum disorder
  • autophagy
  • peroxisome biogenesis disorder
  • peroxisomes
  • pexophagy
  • selective autophagy

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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