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Type: Artigo de periódico
Title: Ca2+ induces a cyclosporin A-insensitive permeability transition pore in isolated potato tuber mitochondria mediated by reactive oxygen species
Author: Fortes, F
Castilho, RF
Catisti, R
Carnieri, EGS
Vercesi, AE
Abstract: Oxidative damage of mammalian mitochondria induced by Ca2+ and prooxidants is mediated by the attack of mirochondria-generated reactive oxygen species on membrane protein thiols promoting oxidation and cross-linkage that leads to the opening of the mitochondrial permeability transition pore (Castilho et al., 1995). In this study, we present evidence that deenergized potato tuber (Solanum tuberosum) mitochondria, which do not possess a Ca2+ uniport, undergo inner membrane permeabilization when treated with Ca2+ (>0.2 mM), as indicated by mitochondrial swelling. Similar to rat liver mitochondria, this permeabilization is enhanced by diamide, a thiol oxidant that creates a condition of oxidative stress by oxidizing pyridine nucleotides. This is inhibited by the antioxidants catalase and dithiothreitol. Potato mitochondrial membrane permeabilization is not inhibited by ADP, cyclosporin A, and ruthenium red, acid is partially inhibited by Mg2+ and acidic pH, well known inhibitors of the mammalian mitochondrial permeability transition. The lack of inhibition of potato mitochondrial permeabilization by cyclosporin A is in contrast to the inhibition of the peptidylprolyl cis-trans isomerase activity, that is related to the cyclosporin A-binding protein cyclophilin. Interestingly, the monofunctional thiol reagent mersalyl induces an extensive cyclosporin A-insensitive potato mitochondrial swelling, even in the presence of lower Ca2+ concentrations (>0.01 mM). In conclusion, we have identified a cyclosporin A-insensitive permeability transition pore in isolated potato mitochondria that is induced by reactive oxygen species.
Subject: calcium
cyclosporin A
mitochondrial permeability transition
plant mitochondria
oxidative stress
Solanum tuberosum
Country: EUA
Editor: Kluwer Academic/plenum Publ
Citation: Journal Of Bioenergetics And Biomembranes. Kluwer Academic/plenum Publ, v. 33, n. 1, n. 43, n. 51, 2001.
Rights: fechado
Identifier DOI: 10.1023/A:1005672623709
Date Issue: 2001
Appears in Collections:Unicamp - Artigos e Outros Documentos

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