Cell Biology

Sequestration Stress

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Science  11 Oct 2013:
Vol. 342, Issue 6155, pp. 165
DOI: 10.1126/science.342.6155.165-c
CREDIT: M. COELHO ET AL., CURRENT BIOLOGY 23 (12 SEPTEMBER 2013) © ELSEVIER LTD

All organisms age—at least that's what we thought until now. Although we are familiar with the signs of aging in multicellular organisms such as ourselves, unicellular organisms also get old though replicative aging, measured as an increase in cell division times and an increased probability of cell death. For example, the budding yeast Saccharomyces cerevisae divides asymmetrically. The larger mother cell ages and normally dies after about 20 divisions. Coelho et al. study the fission yeast Schizosaccharomyces pombe, which has rod-shaped cells that divide symmetrically, and show that under nonstressed conditions, neither of the daughter cells or their progeny age—all cells continue to divide at a roughly constant rate. Making the cell divisions asymmetric, producing larger and smaller daughter cells, also did not result in aging. Cells did occasionally die, but death was not preceded by signs of aging and instead was due to catastrophic failure of a cellular process. Under stressful conditions that cause the aggregation of misfolded proteins, fission yeast cells do age. The daughter cell and her progeny, which sequester the single large protein aggregate from the stressed mother cell, will age, whereas the unencumbered daughters will remain ageless.

Curr. Biol. 23, 10.1016/j.cub.2013.07.084 (2013).

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