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Synthetic lethal and biochemical analyses of NAD and NADH kinases in Saccharomyces cerevisiae establish separation of cellular functions
Journal article   Open access   Peer reviewed

Synthetic lethal and biochemical analyses of NAD and NADH kinases in Saccharomyces cerevisiae establish separation of cellular functions

Pawel Bieganowski, Heather F Seidle, Marzena Wojcik and Charles Brenner
The Journal of biological chemistry, Vol.281(32), pp.22439-22445
08/11/2006
DOI: 10.1074/jbc.M513919200
PMID: 16760478
url
https://doi.org/10.1074/jbc.M513919200View
Published (Version of record) Open Access

Abstract

Production of NADP and NADPH depends on activity of NAD and NADH kinases. Here we characterized all combinations of mutants in yeast NAD and NADH kinases to determine their physiological roles. We constructed a diploid strain heterozygous for disruption of POS5, encoding mitochondrial NADH kinase, UTR1, cytosolic NAD kinase, and YEF1, a UTR1-homologous gene we characterized as encoding a low specific activity cytosolic NAD kinase. pos5 utr1 is a synthetic lethal combination rescued by plasmid-borne copies of the POS5 or UTR1 genes or by YEF1 driven by the ADH1 promoter. Respiratory-deficient and oxidative damage-sensitive defects in pos5 mutants were not made more deleterious by yef1 deletion, and a quantitative growth phenotype of pos5 and its arginine auxotrophy were repaired by plasmid-borne POS5 but not UTR1 or ADH1-driven YEF1. utr1 haploids have a slow growth phenotype on glucose not exacerbated by yef1 deletion but reversed by either plasmid-borne UTR1 or ADH1-driven YEF1. The defect in fermentative growth of utr1 mutants renders POS5 but not POS5-dependent mitochondrial genome maintenance essential because rho-utr1 derivatives are viable. Purified Yef1 has similar nucleoside triphosphate specificity but substantially lower specific activity and less discrimination in favor of NAD versus NADH phosphorylation than Utr1. Low expression and low intrinsic NAD kinase activity of Yef1 and the lack of phenotype associated with yef1 suggest that Utr1 and Pos5 are responsible for essentially all NAD/NADH kinase activity in vivo. The data are compatible with a model in which there is no exchange of NADP, NADPH, or cytoplasmic NAD/NADH kinase between nucleocytoplasmic and mitochondrial compartments, but the cytoplasm is exposed to mitochondrial NAD/NADH kinase during the transit of the molecule.
Amino Acid Sequence Phosphorylation Phosphotransferases (Alcohol Group Acceptor) - physiology Phosphotransferases (Alcohol Group Acceptor) - chemistry Molecular Sequence Data Cytoplasm - metabolism Phosphotransferases (Alcohol Group Acceptor) - genetics Saccharomyces cerevisiae Proteins - genetics Mitochondrial Proteins Phosphotransferases (Alcohol Group Acceptor) - metabolism NAD - chemistry Saccharomyces cerevisiae - metabolism Sequence Homology, Amino Acid Cell Nucleus - metabolism Biochemistry - methods Saccharomyces cerevisiae Proteins - metabolism Cytosol - metabolism Saccharomyces cerevisiae Proteins - physiology Saccharomyces cerevisiae Proteins - chemistry

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