The control of cytochrome C oxidase on the cellular oxidative phosphorylation system depends on the mitochondrial energy state

International audienceRecent measurements of the flux control exerted by cytochrome c oxidase on the respiratory activity in intact cells have led to a re-appraisal of its regulatory function. We have further extended this "in vivo" study in the framework of the metabolic control analysis and evaluated the impact of the mitochondrial transmembrane electrochemical potential ({Delta}{mu}H +}) on the control strength of the oxidase. The outcomes here presented show that, under conditions mimicking the mitochondrial state 4 of respiration both the flux control coefficient and threshold value of cytochrome oxidase are modified with respect to the uncoupled condition. The results obtained are consistent with a model based on changes in the assembly state of the oxidative phosphorylation enzyme complexes and the possible implication for the understanding of the exercise-intolerance of human neuro-muscular degenerative diseases is discussed