Nutrient control of glucose homeostasis through a complex of PGC-1α and SIRT1

JT Rodgers, C Lerin, W Haas, SP Gygi… - Nature, 2005 - nature.com
Nature, 2005nature.com
Homeostatic mechanisms in mammals respond to hormones and nutrients to maintain blood
glucose levels within a narrow range. Caloric restriction causes many changes in glucose
metabolism and extends lifespan; however, how this metabolism is connected to the ageing
process is largely unknown. We show here that the Sir2 homologue, SIRT1—which
modulates ageing in several species,,—controls the gluconeogenic/glycolytic pathways in
liver in response to fasting signals through the transcriptional coactivator PGC-1α. A nutrient …
Abstract
Homeostatic mechanisms in mammals respond to hormones and nutrients to maintain blood glucose levels within a narrow range. Caloric restriction causes many changes in glucose metabolism and extends lifespan; however, how this metabolism is connected to the ageing process is largely unknown. We show here that the Sir2 homologue, SIRT1—which modulates ageing in several species,, —controls the gluconeogenic/glycolytic pathways in liver in response to fasting signals through the transcriptional coactivator PGC-1α. A nutrient signalling response that is mediated by pyruvate induces SIRT1 protein in liver during fasting. We find that once SIRT1 is induced, it interacts with and deacetylates PGC-1α at specific lysine residues in an NAD+-dependent manner. SIRT1 induces gluconeogenic genes and hepatic glucose output through PGC-1α, but does not regulate the effects of PGC-1α on mitochondrial genes. In addition, SIRT1 modulates the effects of PGC-1α repression of glycolytic genes in response to fasting and pyruvate. Thus, we have identified a molecular mechanism whereby SIRT1 functions in glucose homeostasis as a modulator of PGC-1α. These findings have strong implications for the basic pathways of energy homeostasis, diabetes and lifespan.
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