Exploring the Biochemistry of Calorie Restriction
Researchers continue to make solid progress in detailing the biochemical mechanisms by which calorie restriction extends healthy life: "Calorie restriction (CR), the only non-genetic intervention known to slow aging and extend life span in organisms ranging from yeast to mice, has been linked to the down-regulation of Tor, Akt, and Ras signaling. In this study, we demonstrate that the serine/threonine kinase Rim15 is required for yeast chronological life span extension caused [by] calorie restriction. ... Deletion of stress resistance transcription factors Gis1 and Msn2/4, which are positively regulated by Rim15, also caused a major although not complete reversion of the effect of calorie restriction on life span. ... Notably, the anti-aging effect caused by the inactivation of both pathways is much more potent than that caused by CR." Enumerating the required parts of the chain, one by one, is an early step in the process of building a full understanding - and then reproducing and improving upon natural longevity-inducing biochemistry. Interestingly, Rim15 is also required for the recently demonstrated set of genetic tweaks that boost yeast life-span ten-fold - even though that did not involve calorie restriction.