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キーワード:
ATP-Binding Cassette Transporters/*metabolism
Adenosine Triphosphate/chemistry
Biological Transport
Centrifugation, Density Gradient
Chromatography
Cloning, Molecular
Detergents/pharmacology
Dimerization
Dose-Response Relationship, Drug
Electrophoresis, Polyacrylamide Gel
Endopeptidases/chemistry
Glycerol/pharmacology
Mitochondria/*enzymology/metabolism
Mitochondrial Proton-Translocating ATPases/*chemistry/metabolism
Octoxynol/pharmacology
Protein Binding
Saccharomyces cerevisiae/metabolism
*Saccharomyces cerevisiae Proteins
Ultracentrifugation
要旨:
The half-ABC transporter Mdl1 is localized in the inner membrane of mitochondria and mediates the export of peptides generated upon proteolysis of mitochondrial proteins. The physiological role of the peptides released from mitochondria is currently not understood. Here, we have analyzed the oligomeric state of Mdl1 in the inner membrane and demonstrate nucleotide-dependent binding to the F(1)F(0)-ATP synthase. Mdl1 forms homo-oligomeric, presumably dimeric complexes in the presence of ATP, but was found in association with the F(1)F(0)-ATP synthase at low ATP levels. Mdl1 binds membrane-embedded parts of the ATP synthase complex after the assembly of the F(1) and F(0) moieties. Although independent of Mdl1 activity, complex formation is impaired upon inhibition of the F(1)F(0)-ATP synthase with oligomycin or N,N'-dicyclohexylcarbodiimide. These results are consistent with an activation of Mdl1 upon dissociation from the ATP synthase and suggest a link of peptide export from mitochondria to the activity of the F(1)F(0)-ATP synthase and the cellular energy metabolism.
