Abstract
Numerous observations support the existence of senescence factors in yeast. Historically, the asymmetric propagation and accumulation of extra-chromosomal ribosomal DNA circles (ERCs) has been proposed to fulfill this function. On the other hand, several recent papers have re-invigorated the discussion of a potential role for cell size and/or hypertrophy in yeast senescence. While studies have revealed evidence both in favor of and against the hypertrophy model, the prevalent dogma largely discounts a potential role for cell size in the control of cellular lifespan. However, new results not only demonstrate a correlation between cell size and senescence, but allude to a causative role of cell size and hypertrophy in aging. In particular, the degree of hypertrophy, as determined by the rate of cell growth per generation, appears to function as a major determinant of cellular lifespan. Herein, in light of these new data, we examine the recent debate regarding a potential role for cell size in yeast aging, address criticisms of this model, and suggest that the balance is tipping in favor of hypertrophy having a causative role in aging, albeit not as the sole “aging factor.”