Bax and heart mitochondria: uncoupling and inhibition of respiration without permeability transition. - Archive ouverte HAL Access content directly
Journal Articles Biochimica et Biophysica Acta - Molecular Cell Research Year : 2002

Bax and heart mitochondria: uncoupling and inhibition of respiration without permeability transition.

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Abstract

The effects of Bax (full-length, FL, and C-terminal truncated, DeltaC) on respiration rate, membrane potential, MgATPase activity and kinetics of regulation of respiration were studied in isolated rat heart mitochondria and permeabilized cardiomyocytes. The results showed that while both Bax-FL and Bax-DeltaC permeabilized the outer mitochondrial membrane, released cytochrome c and reduced the respiration rate, the latter could be fully restored by exogenous cytochrome c only in the case of Bax-DeltaC, but not in presence of Bax-FL. In addition, Bax-FL but not Bax-DeltaC increased the MgATPase activity, and their effects on the mitochondrial membrane potential were quantitatively different. None of these effects was sensitive to cyclosporin A (CsA).It is concluded that Bax-FL affects both the outer and the inner mitochondrial membranes by: (1) opening large pores in the outer membrane; (2) inhibiting some segments of the respiratory chain in the inner membrane; and (3) uncoupling the inner mitochondrial membrane by increasing proton leak without opening the permeability transition pore (PTP).
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Dates and versions

inserm-00391055 , version 1 (03-06-2009)

Identifiers

  • HAL Id : inserm-00391055 , version 1
  • PUBMED : 12460673

Cite

Florence Appaix, Karen Guerrero, David Rampal, Mohamed Izikki, Tuuli Käämbre, et al.. Bax and heart mitochondria: uncoupling and inhibition of respiration without permeability transition.. Biochimica et Biophysica Acta - Molecular Cell Research, 2002, 1556 (2-3), pp.155-67. ⟨inserm-00391055⟩

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