Recent findings suggest that evolutionarily distant organisms share the key features of the aging process and exhibit similar mechanisms of its modulation by certain genetic, dietary and pharmacological interventions. The scope of this review is to analyze mechanisms that in the yeast Saccharomyces cerevisiae underlie: (1) the replicative and chronological modes of aging; (2) the convergence of these 2 modes of aging into a single aging process; (3) a programmed differentiation of aging cell communities in liquid media and on solid surfaces; and (4) longevity-defining responses of cells to some chemical compounds released to an ecosystem by other organisms populating it. Based on such analysis, we conclude that all these mechanisms are programs for upholding the long-term survival of the entire yeast population inhabiting an ecological niche; however, none of these mechanisms is a "program of aging" - i.e., a program for progressing through consecutive steps of the aging process.
Keywords: D, diauxic growth phase; ERCs, extrachromosomal rDNA circles; IPOD, insoluble protein deposit; JUNQ, juxtanuclear quality control compartment; L, logarithmic growth phase; MBS, the mitochondrial back-signaling pathway; MTC, the mitochondrial translation control signaling pathway; NPCs, nuclear pore complexes; NQ, non-quiescent cells; PD, post-diauxic growth phase; Q, quiescent cells; ROS, reactive oxygen species; RTG, the mitochondrial retrograde signaling pathway; Ras/cAMP/PKA, the Ras family GTPase/cAMP/protein kinase A signaling pathway; ST, stationary growth phase; TOR/Sch9, the target of rapamycin/serine-threonine protein kinase Sch9 signaling pathway; UPRER, the unfolded protein response pathway in the endoplasmic reticulum; UPRmt, the unfolded protein response pathway in mitochondria; cell growth and proliferation; cell survival; cellular aging; ecosystems; evolution; longevity; programmed cell death; yeast; yeast colony; yeast replicative and chronological aging.