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J Biol Chem. 2004 May 7;279(19):20411-21. Epub 2004 Feb 19.

Mobilization of adenine nucleotide translocators as molecular bases of the biochemical threshold effect observed in mitochondrial diseases.

Author information

1
INSERM, Université Victor Segalen-Bordeaux 2, 146 rue Léo-Saignat, F-33076 Bordeaux Cedex, France.

Abstract

The existence of a biochemical threshold effect in the metabolic expression of oxidative phosphorylation deficiencies has considerable implications for the understanding of mitochondrial bioenergetics and the study of mitochondrial diseases. However, the molecular bases of this phenomenon remain unclear. We report here a new mechanism to explain this threshold effect, based on a reserve of enzymes not initially participating in the respiratory rate that can be activated either to respond to a flux increase or to compensate for a defect induced by a mutation. We show that this mobilization occurs through 1) the assembly of inactive adenine nucleotide translocator isoform 1 subunits into oligomeric active carriers or 2) conformational changes in the adenine nucleotide translocator isoform 1 in a permeability transition pore-like structure. We discuss how these transitions are sensitive to the steady state of oxidative phosphorylation functioning or tissue and analyze their consequences on the threshold effect.

PMID:
14976187
DOI:
10.1074/jbc.M314259200
[Indexed for MEDLINE]
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