Sue1p is required for degradation of labile forms of altered cytochromes C in yeast mitochondria.
Previous studies on certain altered holo-isocytochromes c revealed a rho(-)-dependent degradation (RDD) phenotype, in which certain altered holo-iso-1-cytochromes c are at normal or nearly normal levels in rho+ strains, but are at low levels or absent in rho- strains, although wild-type holo-iso-1-cytochrome c is present at normal levels in both rho+ and related rho- 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 rho- sue1 strains. Also, rho+ sue1 strains containing certain altered holo-iso-1-cytochromes c grew better on non-fermentable carbon sources than the corresponding rho+ 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.
Wei
Jun
J
Department of Biochemistry and Biophysics, University of Rochester, School of Medicine and Dentistry, Rochester, New York 14642, USA.
Sherman
Fred
F
D000483:Alleles; D015153:Blotting, Western; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism*; D045304:Cytochromes c / Q000737:chemistry* / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000502:physiology*; D008957:Models, Genetic; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010641:Phenotype; D016133:Polymerase Chain Reaction; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013696:Temperature
D008164:Luminescent Proteins; D024101:Mitochondrial Proteins; D011993:Recombinant Fusion Proteins; C488531:Sue1 protein, S cerevisiae; D049452:Green Fluorescent Proteins; D045304:Cytochromes c