Sue1p Is Required for Degradation of Labile Forms of Altered Cytochromes c in Yeast Mitochondria

• Published in: The Journal of biological chemistry Vol. 279; no. 29; pp. 30449 - 30458
• Main Authors: Wei, Jun, Sherman, Fred
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 16.07.2004
• Subjects: Alleles; Blotting, Western; Cell Division; Cell Nucleus - metabolism; Cytochromes c - chemistry; Cytochromes c - metabolism; Escherichia coli - metabolism; Green Fluorescent Proteins; Luminescent Proteins - metabolism; Mitochondria - metabolism; Mitochondrial Proteins - chemistry; Mitochondrial Proteins - physiology; Models, Genetic; Mutagenesis, Site-Directed; Mutation; Phenotype; Polymerase Chain Reaction; Protein Folding; Protein Structure, Tertiary; Recombinant Fusion Proteins - metabolism; Saccharomyces cerevisiae - metabolism; Temperature
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M403742200

Previous studies on certain altered holo-isocytochromes c revealed a ρ – -dependent degradation (RDD) phenotype, in which certain altered holo-iso-1-cytochromes c are at normal or nearly normal levels in ρ + strains, but are at low levels or absent in ρ – strains, although wild-type holo-iso-1-cytochrome c is present at normal levels in both ρ + and related ρ – strains. The diminished levels of altered holo-iso-1-cytochrome c are due to the rapid degradation that is carried out by a novel proteolytic pathway in the IMS of mitochondria. SUE1 , a nuclear gene that encodes a mitochondrial protein, was identified with a genetic screen for mutants that diminish RDD. The levels of RDD and certain other types of altered holo-iso-1-cytochrome c were elevated in ρ – sue1 strains. Also, ρ + sue1 strains containing certain altered holo-iso-1-cytochromes c grew better on non-fermentable carbon sources than the corresponding ρ + SUE1 strains. These results indicate that Sue1p may play an important role in the degradation of abnormal holo-iso-1-cytochrome c in the mitochondria.