Metabolic control and ageing

There appear to he multiple processes that are limiting for longevity and t he associated mechanisms of ageing. Among these processes, metabolic contro l is coming to the forefront, because it has surfaced in studies in several model systems and because of its relevance to mammalian ageing. The geneti c and molecular dissection of ageing in yeast points to mechanisms involvin g three aspects of metabolism. First, dysfunctional mitochondria signal man y changes in nuclear gene expression that result in metabolic adjustments t hat extend life span. Second, manipulation of nutritional status can also i ncrease longevity in a separate caloric-restriction pathway. Finally, prote in synthesis is a third aspect, which depends on the transcriptional state of chromatin and the histone deacetylases that modulate it.