Figure 2.

Processes involved in the regulation of replicative, chronological and colony ageing. Different molecular processes govern the modulation of yeast longevity, among them processes involved in mitochondrial function, protein quality control and nutrient signalling. Some of the corresponding mechanisms in each ageing model remain to be elucidated; some are specific for a given paradigm, while others either completely or partly overlap. Several mechanisms even result in opposed outcomes: the inactivation of main nutrient signalling pathways (Ras/PKA and TOR–Sch9), for instance, causes replicative and chronological longevity but results in the demise of a colony in the long run, since the region-specific death in its centre is necessary for colony differentiation. Note that the mechanisms shown in the figure represent only examples for each process and do not constitute the entirety of known pathways for each ageing model