Identification of Isn1 and Sdt1 as Glucose- and Vitamin-regulated Nicotinamide Mononucleotide and Nicotinic Acid Mononucleotide 5′-Nucleotidases Responsible for Production of Nicotinamide Riboside and Nicotinic Acid Riboside
| Autor: | Charles R. Evans, Charles F. Burant, Robert T. Kennedy, Peter Belenky, Katrina L. Bogan, Peng Song, Charles Brenner |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Niacinamide
Vitamin Saccharomyces cerevisiae Proteins Pyridinium Compounds Saccharomyces cerevisiae Biology Niacin Biochemistry Gene Knockout Techniques Nucleotidases chemistry.chemical_compound 5'-Nucleotidase Molecular Biology Nicotinamide Mononucleotide Nicotinamide mononucleotide chemistry.chemical_classification Vitamins Cell Biology Metabolism Riboside NAD Metabolism and Bioenergetics Glucose Nicotinic agonist Enzyme Nicotinic acid mononucleotide chemistry Nicotinamide riboside Additions and Corrections Ribonucleosides NAD+ kinase |
| Zdroj: | Journal of Biological Chemistry. 284:34861-34869 |
| ISSN: | 0021-9258 |
| Popis: | Recently, we discovered that nicotinamide riboside and nicotinic acid riboside are biosynthetic precursors of NAD(+), which are utilized through two pathways consisting of distinct enzymes. In addition, we have shown that exogenously supplied nicotinamide riboside is imported into yeast cells by a dedicated transporter, and it extends replicative lifespan on high glucose medium. Here, we show that nicotinamide riboside and nicotinic acid riboside are authentic intracellular metabolites in yeast. Secreted nicotinamide riboside was detected with a biological assay, and intracellular levels of nicotinamide riboside, nicotinic acid riboside, and other NAD(+) metabolites were determined by a liquid chromatography-mass spectrometry method. A biochemical genomic screen indicated that three yeast enzymes possess nicotinamide mononucleotide 5'-nucleotidase activity in vitro. Metabolic profiling of knock-out mutants established that Isn1 and Sdt1 are responsible for production of nicotinamide riboside and nicotinic acid riboside in cells. Isn1, initially classified as an IMP-specific 5'-nucleotidase, and Sdt1, initially classified as a pyrimidine 5'-nucleotidase, are additionally responsible for dephosphorylation of pyridine mononucleotides. Sdt1 overexpression is growth-inhibitory to cells in a manner that depends on its active site and correlates with reduced cellular NAD(+). Expression of Isn1 protein is positively regulated by the availability of nicotinic acid and glucose. These results reveal unanticipated and highly regulated steps in NAD(+) metabolism. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|