Nicotinamide and PNC1 govern lifespan extension by calorie restriction in Saccharomyces cerevisiae.
Level 5 - mechanism / opinion, no new human data
Mechanism-based bench research in yeast (Saccharomyces cerevisiae)
PubMed 12736687 · doi:10.1038/nature01578
What was done
Investigated the molecular pathway linking calorie restriction and low-intensity stress to Sir2-dependent lifespan extension in yeast (*Saccharomyces cerevisiae*), focusing on the nicotinamide-deaminating enzyme encoded by *PNC1* and its regulation of Sir2 activity.
What was found
Increased *PNC1* expression was necessary and sufficient to extend yeast lifespan under calorie restriction and low-intensity stress. *PNC1* acted as a longevity gene responsive to lifespan-extending stimuli, and nicotinamide depletion alone was sufficient to activate Sir2. The abstract reports no quantitative values, statistical metrics, or effect sizes.
Why it matters
This study delineates an enzymatic mechanism (nicotinamide clearance via PNC1) by which calorie restriction relieves Sir2 inhibition to promote longevity in yeast, suggesting a model for how stress responses interface with NAD+-dependent deacetylation.
Limits
Findings are limited strictly to single-celled yeast (*S. cerevisiae*) and mechanism-based laboratory experiments; relevance to mammalian physiology or human aging is unproven. The abstract provides no sample sizes, effect sizes, or quantitative lifespan data.
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