fig1

Figure 1. The hallmarks of cellular senescence. Cellular senescence can be defined as the irreversible growth arrest that occurs when the cells encounter a stressor. Senescent cells differ from other nondividing (quiescent, terminally differentiated) cells in several ways, although no single feature of the senescent phenotype is exclusively specific. The hallmarks of senescent cells include an essentially irreversible growth arrest; expression of senescence associated (SA)-β gal activity and p16INK4a; robust secretion of numerous growth factors, cytokines, proteases, and other proteins (SASP); and nuclear foci containing damaged DNA. SASP: Senescence associated secretory proteins; TERT: telomerase reverse transcriptase.