Chronological
aging and protein oxidative damage.
Gemma Reverter,
Elisa Cabiscol, Jordi Tamarit, Joaquim Ros
Ciencies Mediques Basiques, Facultat de Medicina, Rovira Roure, 44, Lleida,
25198, Spain (gemma.reverter@cmb.udl.es)
Oxidative stress has been related with many pathological conditions, including aging. Yeast aging has been intensively reviewed, although the precise relationship of stress resistance to lifespan is still unclear. In S. cerevisiae, two types of aging have been described. The so-called replicative senescence, measured as the number of daughters produced by each dividing mother cell, and the chronological (non-replicative) senescence, measured as the ability of the stationary cultures to maintain viability over time. Stationary phase induce several enzymes important to detoxify reactive oxygen species, like superoxide dismutase. Therefore, chronological lifespan might be expected to relate to oxidative stress resistance. One of the most important players related to oxidative stress is iron. Fe2+ is involved in Fenton and Haber-Weiss reactions, producing highly reactive oxygen species. Total iron increased two to three-fold in response to chronological senescence, but more important 'free-iron' (properly called labile iron pool), increased strongly in this situation. Carbonyl groups, a marker of protein oxidation, were detected in 2D-gels followed by Western blot. Cells obtained at different days of stationary phase showed an increase in protein carbonylation. There are several target proteins strongly affected during senescence. Identification of these proteins will give us important information to understand their role during aging.