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Plasma membrane NADH‐oxidoreductase in cells carrying mitochondrial DNA G11778A mutation and in cells devoid of mitochondrial DNA (ρ 0 )
Author(s) -
Malik Safarina G.,
Vaillant François,
Lawen Alfons
Publication year - 2004
Publication title -
biofactors
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 94
eISSN - 1872-8081
pISSN - 0951-6433
DOI - 10.1002/biof.5520200402
Subject(s) - biology , mitochondrial dna , oxidoreductase , microbiology and biotechnology , biochemistry , mitochondrion , cell culture , oxidative phosphorylation , enzyme , genetics , gene
The mammalian plasma membrane (PM) NADH‐oxidoreductase (PMOR) system is a multi‐enzyme complex located in the plasma membrane of all eukaryotic cells, harboring at least two distinct activities, the plasma membrane NADH‐ferricyanide reductase and the NADH‐oxidase. To assess the behaviour of the two activities of the PMOR system, we measured the NADH‐ferricyanide reductase and NADH‐oxidase activities in fibroblast cell lines derived from patients carrying a mitochondrial DNA (mtDNA) G11778A mutation. We also measured the two activities in other cell lines, the HL‐60 and HeLa (S3) lines, as well as in ρ 0 cells (cells devoid of mtDNA) generated from those lines and the fibroblast cells. These ρ 0 cells consequently lack oxidative phosphorylation and rely on anaerobic glycolysis for their ATP need. We have proposed that in ρ 0 cells, at least in part, up‐regulation of the PMOR is a necessity to maintain the NAD + /NADH ratio, and a pre‐requisite for cell growth and viability. We show here that the PM NADH‐ferricyanide reductase activity was up‐regulated in HL‐AV2 (HL‐60 ρ 0 ) cell lines, but not in the other ρ 0 and mtDNA mutant lines. The plasma membrane NADH oxidase activity was found to be up‐regulated in both HL‐AV2 and HeLa ρ 0 cell lines, but not significantly in the fibroblast ρ 0 and G11778A lines.