Afg3p, a mitochondrial ATP-dependent metalloprotease, is involved in degradation of mitochondrially-encoded Cox1, Cox3, Cob, Su6, Su8 and Su9 subunits of the inner membrane complexes III, IV and V.
The yeast AFG3 gene encodes an ATP-dependent metalloprotease belonging to a subgroup of the AAA-family. This protease has been suggested to be essential for a metal- and ATP-dependent breakdown of incompletely mitochondrially synthesized polypeptides in the inner membrane, a process proposed to be important for mitochondrial function (Pajic et al. (1994) FEBS Lett. 353, 201-206). Here, we confirm the proteolytic activity by site-directed mutagenesis and demonstrate that the proteins Cox1, Cox3, Cob, Su6, Su8 and Su9 are substrates of Afg3p. Surprisingly, this proteolytic activity is not required for respiratory function and thus presumably also not essential for mitochondrial biogenesis.
Guzélin
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Section for Molecular Biology, Department of Molecular Biology, University of Amsterdam, The Netherlands.
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Grivell
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D000251:Adenosine Triphosphatases / Q000096:biosynthesis / Q000378:metabolism*; D001483:Base Sequence; D002352:Carrier Proteins; D014450:Electron Transport Complex III / Q000096:biosynthesis / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000096:biosynthesis / Q000378:metabolism*; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D007425:Intracellular Membranes / Q000201:enzymology; D007700:Kinetics; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000096:biosynthesis / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology*; D025261:Mitochondrial Proton-Translocating ATPases; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010641:Phenotype; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D013045:Species Specificity
D002352:Carrier Proteins; D005656:Fungal Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases; C090045:AFG3 protein, S cerevisiae; D025261:Mitochondrial Proton-Translocating ATPases; D014450:Electron Transport Complex III; C020439:oligomycin sensitivity-conferring protein