The role of autophagy in mitochondria maintenance: Characterization of mitochondrial functions in autophagy-deficient S. cerevisiae strains

Yong Zhang, Haiyan Qi, Robert Taylor, Weihong Xu, Leroy-Fong Liu, Shengkan Jin

Research output: Contribution to journalArticle

163 Citations (Scopus)

Abstract

Autophagy is a lysosome-dependent cellular degradation process. Organisms bearing deletions of the essential autophagy genes exhibit various pathological conditions, including cancer in mammals and shortened life span in C. elegans. The direct cause for these phenotypes is not clear. Here we used yeast as a model system to characterize the cellular consequence of ATG (autophagy-related) gene deletions. We found that the atg mutant strains, atg1Δ, atg6Δ, atg8Δ and atg12Δ, showed defects related to mitochondrial biology. These strains were unable to degrade mitochondria in stationary culture. In non-fermentable medium, which requires mitochondrial oxidative phosphorylation for survival, these atg strains showed a growth defect with an increased cell population at the G1 phase of the cell cycle. The cells had lower oxygen consumption rates and reduced mitochondrial electron transport chain activities. Under these growth conditions, the atg strains had lower mitochondrial membrane potential. In addition, these mutants generated higher levels of reactive oxygen species (ROS) and they were prone to accumulate dysfunctional mitochondria. This study clearly indicates that an autophagy defect has a functional impact on various aspects of mitochondrial functions and suggests a critical role of autophagy in mitochondria maintenance.

Original languageEnglish
Pages (from-to)337-346
Number of pages10
JournalAutophagy
Volume3
Issue number4
Publication statusPublished - Jul 2007
Externally publishedYes

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Keywords

  • Autophagy
  • Mitochondrial function
  • Oxidative phosphorylation
  • Petite
  • Reactive oxygen species
  • S. Cerevisiae

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology

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