#8 NS 160 Sirtuins

#8 NS 160 Sirtuins - Sir tuins Metabolic Regulation...

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Sirtuins - Metabolic Regulation & Longevity
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Caloric Restriction Caloric restriction (CR), normally defined as a 20-40% reduction in caloric intake without malnutrition, extends the longevity in yeast, spiders, worms, flies, fish, mice, rats and rhesus monkeys CR protects from many aging associated pathophysiologies including type-2 diabetes, atherosclerosis, oxidative damage and senescence of the immune system
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CR and Longevity - Why & How Live extension due to CR may represent adaptation to scarcity. Slowing down aging and reproduction during scarcity maximizes chances of survival and reproduction when food is available again. CR affects many metabolic pathways. Mammalian signaling pathways involved in CR effect on aging are not completely understood but include insulin signaling, AMPK activation and Sirtuins
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CR and Longevity - Why & How Live extension due to CR may represent adaptation to scarcity. Slowing down aging and reproduction during scarcity maximizes chances of survival and reproduction when food is available again. CR affects many metabolic pathways. Mammalian signaling pathways involved in CR effect on aging are not completely understood but include insulin signaling, AMPK activation and Sirtuins
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Sirtuins are mediators of CR The yeast protein Sir2 (silent information regulator 2) was isolated in a screen for silencing factors of the mating locus and later found to extend lifespan in S. cerevisiae. Humans express 7 Sir2 homologs (sirtuins SIRT1-7) that differ in their subcellular localization. CR enhances sirtuin expression and CR dependent lifespan extension in sirtuin- deficient yeast and mice is abolished.
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Sirtuins are mediators of CR The yeast protein Sir2 (silent information regulator 2) was isolated in a screen for silencing factors of the mating locus and later found to extend lifespan in S. cerevisiae. Humans express 7 Sir2 homologs (sirtuins SIRT1-7) that differ in their subcellular localization. CR enhances sirtuin expression and CR dependent lifespan extension in sirtuin- deficient yeast and mice is abolished.
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Sirtuins and Nutrient Sensing Sirtuins are NAD + -dependent protein deacetylases. CR may activate sirtuins by changing the redox balance between NADH and NAD + . Alternatively, CR may decrease nicotinamide (a product and inhibitor of SIRT1 catalytic activity). In mammalian cells Nampt (NAM phosphoribosyltransferase) is the rate- limiting enzyme of the NAM -> NAD+ resynthesis pathway and regulation of Nampt activity by CR can lead to SIRT1 activation
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Sirtuins and Nutrient Sensing Sirtuins are NAD + -dependent protein deacetylases.
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