Flux-force relationships in intact cells: a helpful tool for understanding the mechanism of oxidative phosphorylation alterations?
On isolated mitochondria, numerous studies of the relationships between fluxes and their associated forces have led to the description of some properties of the oxidative phosphorylation pathway. However whether such an approach can be applied to understanding the actual situation in intact living cells needs further consideration. In this study on isolated hepatocytes, we describe the dependence of the respiratory rate on the three thermodynamic forces linked to oxidative phosphorylation (i.e. the redox span over the respiratory chain, the electrical potential difference across the inner mitochondrial membrane and the free energy of ATP synthesis reaction). Even if this description is phenomenological and some objections may be raised regarding the relevance of such a bulk-phase force estimation, we present some results showing that the study of flux-force relationships in intact cells may be a helpful approach for understanding the mechanisms by which oxidative phosphorylation activity is changed.
Institut de Biochimie et Génétique Cellulaires du C.N.R.S., Université de Bordeaux, Bordeaux, France. Michel.Rigoulet@ibgc.u-bordeaux2.fr
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D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004734:Energy Metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D010085:Oxidative Phosphorylation; D006180:Proton-Translocating ATPases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013816:Thermodynamics
D005231:Fatty Acids, Unsaturated; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases