Nicotinamide adenine dinucleotide (NAD(+)) is an essential substrate for sirtuins and poly(adenosine diphosphate-ribose) polymerases (PARPs), which are NAD(+)-consuming enzymes localized in the nucleus, cytosol, and mitochondria. Fluctuations in NAD(+) concentrations within these subcellular compartments are thought to regulate the activity of NAD(+)-consuming enzymes; however, the challenge in measuring compartmentalized NAD(+) in cells has precluded direct evidence for this type of regulation. We describe the development of a genetically encoded fluorescent biosensor for directly monitoring free NAD(+) concentrations in subcellular compartments. We found that the concentrations of free NAD(+) in the nucleus, cytoplasm, and mitochondria approximate the Michaelis constants for sirtuins and PARPs in their respective compartments. Systematic depletion of enzymes that catalyze the final step of NAD(+) biosynthesis revealed cell-specific mechanisms for maintaining mitochondrial NAD(+) concentrations.
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http://dx.doi.org/10.1126/science.aad5168 | DOI Listing |
J Ginseng Res
January 2025
Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea.
Background: Ginseng Berry Concentrate (GBC) enhances exercise capacity in mice, but the effects of its key component, ginsenoside Re (G-Re), on aging and mitochondrial function are not well understood. This study investigates the impact of G-Re on mitophagy and its potential to promote healthy aging.
Methods: Experiments in C2C12 myocytes and HeLa-mitoKeima-PARKIN cells assessed GBC and G-Re's effects on mitophagy, supported by Gene Set Enrichment Analysis.
Plant Cell
January 2025
Department of Biology, University of Oxford, South Parks Road, Oxford, OX1 3RB, United Kingdom.
C4 photosynthesis is a highly efficient form of photosynthesis that utilises a biochemical pump to concentrate CO2 around rubisco. Although variation in the implementation of this biochemical pump exists between species, each variant of the C4 pathway is critically dependent on metabolite transport between organelles and between cells. Here we review our understanding of metabolite transport in C4 photosynthesis.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
January 2025
Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
The enzyme D-sorbitol dehydrogenase (SLDH) facilitates the conversion of D-sorbitol to L-sorbose. While current knowledge of this enzyme class predominantly centers on Gluconobacter oxydans, the catalytic properties of enzymes from alternative sources, particularly their substrate specificity and coenzyme dependency, remain ambiguous. In this investigation, we conducted BLASTp analysis and screened out a novel SLDH (Fpsldh) from Faunimonas pinastri A52C2.
View Article and Find Full Text PDFTriple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with no targeted treatments currently available. TNBC cells participate in metabolic symbiosis, a process that optimizes tumor growth by balancing metabolic processes between glycolysis and oxidative phosphorylation through increased activity by the enzyme lactate dehydrogenase B (LDHB). Metabolic symbiosis allows oxidative cancer cells to function at a similar rate as glycolytic cancer cells, increasing overall metabolic activity and proliferation.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
Centre for Nanomaterials and Biotechnology, Faculty of Science, University of Jan Evangelista Purkyně, Pasteurova 15, 400 96 Ústí nad Labem, Czech Republic.
Surface modification of various polymer foils was achieved by UV activation and chemical grafting with cysteamine to improve surface properties and antimicrobial efficacy. UVC activation at 254 nm led to changes in surface wettability and charge density, which allowed the introduction of amino and thiol functional groups by cysteamine grafting. X-ray photoelectron spectroscopy (XPS) confirmed increased nitrogen and sulfur content on the modified surfaces.
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