Division of Biological Sciences, Section of Molecular Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0377, USA.
Cell. 2010 Jul 23;142(2):256-69. doi: 10.1016/j.cell.2010.06.006. Epub 2010 Jul 8.
The endoplasmic reticulum (ER) plays an essential role in the production of lipids and secretory proteins. Because the ER cannot be generated de novo, it must be faithfully transmitted or divided at each cell division. Little is known of how cells monitor the functionality of the ER during the cell cycle or how this regulates inheritance. We report here that ER stress in S. cerevisiae activates the MAP kinase Slt2 in a new ER stress surveillance (ERSU) pathway, independent of the unfolded protein response. Upon ER stress, ERSU alters the septin complex to delay ER inheritance and cytokinesis. In the absence of Slt2 kinase, the stressed ER is transmitted to the daughter cell, causing the death of both mother and daughter cells. Furthermore, Slt2 is activated via the cell surface receptor Wsc1 by a previously undescribed mechanism. We conclude that the ERSU pathway ensures inheritance of a functional ER.
内质网（ER）在脂质和分泌蛋白的产生中发挥着重要作用。由于内质网不能从头生成，因此它必须在每次细胞分裂时被准确地传递或分裂。目前还不清楚细胞在细胞周期中如何监测内质网的功能，以及这种功能如何调节遗传。我们在这里报告，酿酒酵母中的内质网应激通过一个新的内质网应激监测（ERSU）途径激活丝裂原活化蛋白激酶 Slt2，该途径独立于未折叠蛋白反应。在内质网应激时，ERSU 改变了隔膜复合物以延迟内质网的遗传和胞质分裂。在缺乏 Slt2 激酶的情况下，应激的内质网被传递到子细胞，导致母细胞和子细胞都死亡。此外，Slt2 通过以前未描述的机制被细胞表面受体 Wsc1 激活。我们得出结论，ERSU 途径确保了功能正常的内质网的遗传。
