Dietary Restriction and Nutrient Balance in Aging

Figure 1

Scheme of longevity regulatory pathways in various model organisms (yeast, worms, flies, and mammals). Identical symbols are used for the orthologous genes in each model organism. In worms, flies, and mammals, dietary restriction reduces signalling through IIS/TOR pathways, deactivating the PI3K/Akt/TOR intracellular signalling cascade and consequently activating the antiaging FOXO family transcription factor(s), known to regulate stress resistance and aging. In yeast, dietary restriction reduces the activity of the TOR/Sch9 and RAS/PKA nutrient-signalling pathways, both converging on the protein kinase Rim15 that in consequence activates its downstream transcription factors Gis1 and Msn2/4, involved in the postdiauxic shift (PDS) element-driven gene expression and stress-responsive elements (STRE) gene expression, respectively. The involvement of RAS signalling in longevity regulation is indicated in the two models where it has been described. lysine (Lys.), methionine (Met.), threonine (Thr.), and valine (Val.). The detailed description and other abbreviations are given in the text.