POS5 gene of Saccharomyces cerevisiae encodes a mitochondrial NADH kinase required for stability of mitochondrial DNA.

Abstract

In a search for nuclear genes that affect mutagenesis of mitochondrial DNA in Saccharomyces cerevisiae, an ATP-NAD (NADH) kinase, encoded by POS5, that functions exclusively in mitochondria was identified. The POS5 gene product was overproduced in Escherichia coli and purified without a mitochondrial targeting sequence. A direct biochemical assay demonstrated that the POS5 gene product utilizes ATP to phosphorylate both NADH and NAD(+), with a twofold preference for NADH. Disruption of POS5 increased minus-one frameshift mutations in mitochondrial DNA 50-fold, as measured by the arg8(m) reversion assay, with no increase in nuclear mutations. Also, a dramatic increase in petite colony formation and slow growth on glycerol or limited glucose were observed. POS5 was previously described as a gene required for resistance to hydrogen peroxide. Consistent with a role in the mitochondrial response to oxidative stress, a pos5 deletion exhibited a 28-fold increase in oxidative damage to mitochondrial proteins and hypersensitivity to exogenous copper. Furthermore, disruption of POS5 induced mitochondrial biogenesis as a response to mitochondrial dysfunction. Thus, the POS5 NADH kinase is required for mitochondrial DNA stability with a critical role in detoxification of reactive oxygen species. These results predict a role for NADH kinase in human mitochondrial diseases.

• Authors: Micheline K Strand, Gregory R Stuart, Matthew J Longley, Maria A Graziewicz, Olivia C Dominick, William C Copeland
• Journal: Eukaryotic cell (Eukaryot Cell) Vol. 2 Issue 4 Pg. 809-20 (Aug 2003) ISSN: 1535-9778 [Print] United States
• PMID: 12912900 (Publication Type: Journal Article, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• DNA, Mitochondrial
• Mitochondrial Proteins
• Reactive Oxygen Species
• Saccharomyces cerevisiae Proteins
• NAD
• Copper
• Adenosine Triphosphate
• Phosphotransferases (Alcohol Group Acceptor)
• POS5 protein, S cerevisiae

Topics

• Adenosine Triphosphate (metabolism)
• Cells, Cultured
• Copper (pharmacology)
• DNA, Mitochondrial (genetics)
• Energy Metabolism (genetics)
• Escherichia coli (enzymology, genetics)
• Mitochondria (enzymology, genetics)
• Mitochondrial Diseases (enzymology, genetics)
• Mitochondrial Proteins
• Mutation (genetics)
• NAD
• Oxidative Stress (genetics)
• Phosphorylation
• Phosphotransferases (Alcohol Group Acceptor) (genetics, isolation & purification, physiology)
• Reactive Oxygen Species (metabolism)
• Saccharomyces cerevisiae (enzymology, genetics)
• Saccharomyces cerevisiae Proteins (genetics, isolation & purification, physiology)