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Effects of a transition from normoxia to ... ions for hypoxic gene induction
Effects of a transition from normoxia to anoxia on yeast cytochrome c oxidase and the mitochondrial respiratory chain: implications for hypoxic gene induction.
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Previous studies have demonstrated that the mitochondrial respiratory chain and cytochrome c oxidase participate in oxygen sensing and the induction of some hypoxic nuclear genes in eukaryotes. In addition, it has been proposed that mitochondrially-generated reactive oxygen and nitrogen species function as signals in a signaling pathway for the induction of hypoxic genes. To gain insight concerning this pathway, we have looked at changes in the functionality of the yeast respiratory chain as cells experience a shift from normoxia to anoxia. These studies have revealed that yeast cells retain the ability to respire at normoxic levels for up to 4 h after a shift and that the mitochondrial cytochrome levels drop rapidly to 30--50% of their normoxic levels and the turnover rate of cytochrome c oxidase (COX) increases during this shift. The increase in COX turnover rate cannot be explained by replacing the aerobic isoform, Va, of cytochrome c oxidase subunit V with the more active hypoxic isoform, Vb. We have also found that mitochondria retain the ability to respire, albeit at reduced levels, in anoxic cells, indicating that yeast cells maintain a functional mitochondrial respiratory chain in the absence of oxygen. This raises the intriguing possibility that the mitochondrial respiratory chain has a previously unexplored role in anoxic cells and may function with an alternative electron acceptor when oxygen is unavailable.
David PS, Poyton RO
Biochimica et biophysica acta
2005-09-05 00:00
1709
2
169-80
Anaerobiosis,Cytochromes,Electron Transport,Electron Transport Complex IV,Fatty Acid Desaturases,Gene Expression Regulation, Fungal,Isoenzymes,Mitochondria,Oxygen,Saccharomyces cerevisiae,Saccharomyces cerevisiae Proteins,Cytochromes,Isoenzymes,Saccharomyces cerevisiae Proteins,Oxygen,Fatty Acid Desaturases,delta-9 fatty acid desaturase,Electron Transport Complex IV
The Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
Biochim. Biophys. Acta
NIGMS GM30228
0006-3002
10.1016/j.bbabio.2005.07.002
S0005-2728(05)00166-0
1030
True
16084486
