Calcium-dependent nonspecific permeability of the inner mitochondrial membrane is not induced in mitochondria of the yeast Endomyces magnusii

Mitochondria of the yeast Endomyces magnusii were examined for the presence of a Ca2+- and phosphate-induced permeability of the inner mitochondrial membrane (pore). For this purpose, coupled mitochondria were incubated under conditions known to induce the permeability transition pore in animal mito...

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Bibliographic Details
Published in:Biochemistry (Moscow) 2004-09, Vol.69 (9), p.1025-1033
Main Authors: Deryabina, Y I, Isakova, E P, Shurubor, E I, Zvyagilskaya, R A
Format: Article
Language:English
Subjects:
Adenosine diphosphate
Biochemistry
Calcium - metabolism
Calcium - pharmacology
Cellular biology
Intracellular Membranes - drug effects
Intracellular Membranes - metabolism
Mitochondria
Mitochondria - drug effects
Mitochondria - metabolism
Mitochondrial Proteins - analysis
Mitochondrial Swelling - drug effects
Permeability
Permeability - drug effects
Phosphates - pharmacology
Reagents
Saccharomycetales - drug effects
Saccharomycetales - metabolism
Yeast fungi
Yeasts
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Summary:Mitochondria of the yeast Endomyces magnusii were examined for the presence of a Ca2+- and phosphate-induced permeability of the inner mitochondrial membrane (pore). For this purpose, coupled mitochondria were incubated under conditions known to induce the permeability transition pore in animal mitochondria, i.e., in the presence of high concentrations of Ca2+ and P(i), prooxidants (t-butylhydroperoxide), oxaloacetate, atractyloside (an inhibitor of ADP/ATP translocator), SH-reagents, by depletion of adenine nucleotide pools, and deenergization of the mitochondria. Large amplitude swelling, collapse of the membrane potential, and efflux of the accumulated Ca2+ were used as parameters for demonstrating pore induction. E. magnusii mitochondria were highly resistant to the above-mentioned substances. Deenergization of mitochondria or depletion of adenine nucleotide pools have no effect on low-amplitude swelling or the other parameters. Cyclosporin A, a specific inhibitor of the nonspecific permeability transition in animal mitochondria, did not affect the parameters measured. It is thus evident that E. magnusii mitochondria lack a functional Ca2+-dependent pore, or possess a pore differently regulated as compared to that of mammalian mitochondria.
ISSN:0006-2979
1608-3040
DOI:10.1023/B:BIRY.0000043545.32343.50