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Autophagy. 2013 Nov 1;9(11):1828-36. doi: 10.4161/auto.26281. Epub 2013 Sep 6.

Proteolytic processing of Atg32 by the mitochondrial i-AAA protease Yme1 regulates mitophagy.

Author information

1
Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology; University of Michigan; Ann Arbor, MI USA.

Abstract

Mitophagy, the autophagic removal of mitochondria, occurs through a highly selective mechanism. In the yeast Saccharomyces cerevisiae, the mitochondrial outer membrane protein Atg32 confers selectivity for mitochondria sequestration as a cargo by the autophagic machinery through its interaction with Atg11, a scaffold protein for selective types of autophagy. The activity of mitophagy in vivo must be tightly regulated considering that mitochondria are essential organelles that produce most of the cellular energy, but also generate reactive oxygen species that can be harmful to cell physiology. We found that Atg32 was proteolytically processed at its C terminus upon mitophagy induction. Adding an epitope tag to the C terminus of Atg32 interfered with its processing and caused a mitophagy defect, suggesting the processing is required for efficient mitophagy. Furthermore, we determined that the mitochondrial i-AAA protease Yme1 mediated Atg32 processing and was required for mitophagy. Finally, we found that the interaction between Atg32 and Atg11 was significantly weakened in yme1∆ cells. We propose that the processing of Atg32 by Yme1 acts as an important regulatory mechanism of cellular mitophagy activity.

KEYWORDS:

mitochondrial protease; mitophagy; starvation; vacuole; yeast

PMID:
24025448
PMCID:
PMC4028336
DOI:
10.4161/auto.26281
[Indexed for MEDLINE]
Free PMC Article

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