Uth1p is involved in the autophagic degradation of mitochondria.
The absence of the outer mitochondrial membrane protein Uth1p was found to induce resistance to rapamycin treatment and starvation, two conditions that induce the autophagic process. Biochemical studies showed the onset of a fully active autophagic activity both in wild-type and Deltauth1 strains. On the other hand, the disorganization of the mitochondrial network induced by rapamycin treatment or 15 h of nitrogen starvation was followed in cells expressing mitochondria-targeted green fluorescent protein; a rapid colocalization of green fluorescent protein fluorescence with vacuole-selective FM4-64 labeling was observed in the wild-type but not in the Deltauth1 strain. Degradation of mitochondrial proteins, followed by Western blot analysis, did not occur in mutant strains carrying null mutations of the vacuolar protease Pep4p, the autophagy-specific protein Atg5p, and Uth1p. These data show that, although the autophagic machinery was fully functional in the absence of Uth1p, this protein is involved in the autophagic degradation of mitochondria.
Kissová
Ingrid
I
Unité Mixte de Recherche 5095 CNRS, Université de Bordeaux 2, 33077 Bordeaux, France.
Deffieu
Maïka
M
Manon
Stéphen
S
Camougrand
Nadine
N
D000469:Alkaline Phosphatase / Q000378:metabolism; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism; D001343:Autophagy; D015153:Blotting, Western; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism / Q000502:physiology*; D007425:Intracellular Membranes / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins; D009584:Nitrogen / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism / Q000502:physiology*; D020123:Sirolimus / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D013997:Time Factors
D006360:Heat-Shock Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; C116477:UTH1 protein, S cerevisiae; D049452:Green Fluorescent Proteins; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D003513:Cycloheximide; D000469:Alkaline Phosphatase; C022325:aspartic proteinase A; D016282:Aspartic Acid Endopeptidases; D009584:Nitrogen; D020123:Sirolimus