Abstract
Unlike many other organisms, the yeast Saccharomyces cerevisiae can tolerate the loss of mitochondrial DNA (mtDNA). Although a few proteins have been identified that are required for yeast cell viability without mtDNA, the mechanism of mtDNA-independent growth is not completely understood. To probe the relationship between the mitochondrial genome and cell viability, we conducted a microarray-based, genomewide screen for mitochondrial DNA-dependent yeast mutants. Among the several genes that we discovered is MGR1, which encodes a novel subunit of the i-AAA protease complex located in the mitochondrial inner membrane. mgr1Delta mutants retain some i-AAA protease activity, yet mitochondria lacking Mgr1p contain a misassembled i-AAA protease and are defective for turnover of mitochondrial inner membrane proteins. Our results highlight the importance of the i-AAA complex and proteolysis at the inner membrane in cells lacking mitochondrial DNA.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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ATP-Dependent Proteases
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Adenosine Triphosphatases / genetics
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Adenosine Triphosphatases / metabolism
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DNA, Mitochondrial / genetics
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Genetic Testing
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Genome, Fungal / genetics*
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Metalloendopeptidases / chemistry*
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Metalloendopeptidases / genetics
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Metalloendopeptidases / metabolism*
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Mitochondrial Proteins / genetics
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Mitochondrial Proteins / metabolism
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Mutation / genetics
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Phenotype
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Protein Binding
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Protein Subunits / genetics
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Protein Subunits / metabolism
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Saccharomyces cerevisiae / classification
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Saccharomyces cerevisiae / enzymology
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
Substances
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DNA, Mitochondrial
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Mitochondrial Proteins
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Protein Subunits
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Saccharomyces cerevisiae Proteins
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ATP-Dependent Proteases
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YME1 protein, S cerevisiae
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Metalloendopeptidases
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intermembrane space AAA protease-1
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Adenosine Triphosphatases