Department of Cell and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, 413 90 Göteborg, Sweden.
Cell. 2010 Jan 22;140(2):257-67. doi: 10.1016/j.cell.2009.12.031.
The paradigm sirtuin, Sir2p, of budding yeast is required for establishing cellular age asymmetry, which includes the retention of damaged and aggregated proteins in mother cells. By establishing the global genetic interaction network of SIR2 we identified the polarisome, the formin Bni1p, and myosin motor protein Myo2p as essential components of the machinery segregating protein aggregates during mitotic cytokinesis. Moreover, we found that daughter cells can clear themselves of damage by a polarisome- and tropomyosin-dependent polarized flow of aggregates into the mother cell compartment. The role of Sir2p in cytoskeletal functions and polarity is linked to the CCT chaperonin in sir2Delta cells being compromised in folding actin. We discuss the findings in view of recent models hypothesizing that polarity may have evolved to avoid clonal senescence by establishing an aging (soma-like) and rejuvenated (germ-like) lineage.
模式酵母 Sirt2p 对于建立细胞年龄不对称性是必需的，其中包括将受损和聚集的蛋白质保留在母细胞中。通过建立 SIR2 的全局遗传相互作用网络，我们鉴定出极体、formin Bni1p 和肌球蛋白马达蛋白 Myo2p 是在有丝分裂胞质分裂过程中分离蛋白质聚集体的机器的必需成分。此外，我们发现子细胞可以通过聚集体进入母细胞隔室的极化依赖性流来清除自身损伤。Sir2p 在细胞骨架功能和极性中的作用与 CCT 伴侣蛋白在 sir2Delta 细胞中折叠肌动蛋白的能力受损有关。我们根据最近的模型讨论了这些发现，这些模型假设极性可能是通过建立一个衰老（体样）和恢复活力（生殖样）的谱系来避免克隆衰老而进化的。
