A genomewide screen for petite-negative yeast strains yields a new subunit of the i-AAA protease complex.
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.
Dunn
Cory D
CD
Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Lee
Marina S
MS
Spencer
Forrest A
FA
Jensen
Robert E
RE
D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics; D005820:Genetic Testing; D016681:Genome, Fungal / Q000235:genetics*; D008666:Metalloendopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011485:Protein Binding; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000145:classification / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism
D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D049069:ATP-Dependent Proteases; C082702:YME1 protein, S cerevisiae; D008666:Metalloendopeptidases; C439314:intermembrane space AAA protease-1; D000251:Adenosine Triphosphatases