Sir2p-dependent protein segregation gives rise to a superior reactive oxygen species management in the progeny of Saccharomyces cerevisiae.

Yeast cytokinesis entails a rejuvenation process by which the aged mother cell generates daughter cells enjoying full replicative potential. Here we show that this process includes a precipitous reduction in the levels of reactive oxygen species in the progeny immediately after completion of cytokinesis. The reduction in hydrogen peroxide is the result of a Sir2p and actin cytoskeleton-dependent segregation of the cytosolic catalase Ctt1p such that the daughter cell receives a higher load of undamaged and active Ctt1p than the progenitor cell. Such spatial quality control provides the daughter cells with a superior capacity to combat external oxidative stress and delays self-inflicted oxidative damage to their cellular proteins.