Microscopy Unit, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, 142 20, Czech Republic.
Department of Membrane Biochemistry, Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Ivanka pri Dunaji, 900 28, Slovakia.
Eur J Cell Biol. 2017 Sep;96(6):591-599. doi: 10.1016/j.ejcb.2017.05.001. Epub 2017 May 3.
We describe a novel mechanism of mRNA decay regulation, which takes place under the conditions of glucose deprivation in the yeast Saccharomyces cerevisiae. The regulation is based on temporally stable sequestration of the main 5'-3' mRNA exoribonuclease Xrn1 at the eisosome, a plasma membrane-associated protein complex organizing a specialized membrane microdomain. As documented by monitoring the decay of a specific mRNA substrate in time, Xrn1-mediated mRNA degradation ceases during the accumulation of Xrn1 at eisosome, but the eisosome-associated Xrn1 retains its functionality and can be re-activated when released to cytoplasm following the addition of glucose. In cells lacking the eisosome organizer Pil1, Xrn1 does not associate with the plasma membrane and its activity is preserved till the stationary phase. Thus, properly assembled eisosome is necessary for this kind of Xrn1 regulation, which occurs in a liquid culture as well as in a differentiated colony.
我们描述了一种在酵母酿酒酵母葡萄糖饥饿条件下发生的 mRNA 降解调控的新机制。这种调控是基于主要的 5' - 3 'mRNA 外切核酸酶 Xrn1 在 eisosome （一种与质膜相关的蛋白复合物，组织一个专门的膜微区）上的暂时稳定的隔离。通过监测特定 mRNA 底物在时间上的降解情况，我们记录到 Xrn1 介导的 mRNA 降解在 Xrn1 在 eisosome 上积累期间停止，但与 eisosome 相关的 Xrn1 保留其功能，并且可以在添加葡萄糖后释放到细胞质中时重新激活。在缺乏 eisosome 组织者 Pil1 的细胞中，Xrn1 不会与质膜结合，其活性一直保持到静止期。因此，适当组装的 eisosome 是这种 Xrn1 调控所必需的，这种调控不仅发生在液体培养中，也发生在分化的菌落中。
