Revisiting Sirtuins

I was looking at a review of what is known of the role of sirtuins in aging and longevity earlier today: Calorie restriction lengthens lifespan, in part, due to mitochondrial metabolism reorganization through [sirtuin 1-regulated] mitochondrial biogenesis. This reduces radical oxygen species levels that cause macromolecule damage, a major contributor to aging. Little is known about these processes in stem cells, whose longevity is implicated in human aging. Recent work indicates that sirtuin 1 influences growth-factor responses and maintenance of stem cells. Sirtuin 1 is required for calorie restriction-induced lifespan extension in mice, and calorie restriction upregulates sirtuin 1 in humans. Sirtuin 1 also appears to influence lineage/cell-fate decisions of stem cells via redox status. I notice that sirtuins are also theorized to link processes important to cancer suppression and processes important to insulin metabolism (one of the important metabolic determinants of life span), which is why rate of aging and cancer risk seem balanced against one another in most organisms: Recent evidence suggests that the sirtuin family of proteins act as central mediators of this molecular crosstalk. The coordination of DNA repair with overall energy balance may be essential for reducing the risk of developing cancer as well as...