A novel role of the budding yeast separin Esp1 in anaphase spindle elongation: evidence that proper spindle association of Esp1 is regulated by Pds1.
A novel role of the budding yeast separin Esp1 in anaphase spindle elongation: evidence that proper spindle association of Esp1 is regulated by Pds1.
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DOI：
10.1083/jcb.152.1.27
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发表时间：
2001-01-08
影响因子：
7.8
通讯作者：
Reed, S I
中科院分区：
文献类型：
--
作者：
Jensen, S;Segal, M;Clarke, D J;Reed, S I
在酿酒酵母中，Pds1的中期-后期转变是由后期促进复合体依赖的降解启动的，由此ESP1被激活以促进姐妹染色单体的分离。虽然这是细胞周期中的基本步骤，但人们对ESP1的调节以及凝聚力的丧失如何与后期纺锤体的运动相协调知之甚少。在这里，我们证明了ESP1在促进后期纺锤体延长方面具有新的作用。通过活细胞成像分析，ESP1在纺锤体上的定位是以一种与后期B的功能一致的方式调节的。蛋白质在G2期积累在细胞核中，并在后期开始动员到纺锤体和纺锤体中间区，在那里它持续到中期。与Pds1的结合发生在S期，是有效的核靶向ESP1所必需的。在表达ESP1-核定位序列融合蛋白的pds1突变体中，纺锤体关联没有完全恢复，这表明pds1也是促进ESP1纺锤体结合所必需的。结果表明，Pds1在中后期与纺锤体发生相互作用，在后期细胞的纺锤体极体和纺锤体中间区残留了一小部分。最后，突变分析表明，ESP1保守的COOH末端区域对纺锤体相互作用是重要的。
In Saccharomyces cerevisiae, the metaphase–anaphase transition is initiated by the anaphase-promoting complex–dependent degradation of Pds1, whereby Esp1 is activated to promote sister chromatid separation. Although this is a fundamental step in the cell cycle, little is known about the regulation of Esp1 and how loss of cohesion is coordinated with movement of the anaphase spindle. Here, we show that Esp1 has a novel role in promoting anaphase spindle elongation. The localization of Esp1 to the spindle apparatus, analyzed by live cell imaging, is regulated in a manner consistent with a function during anaphase B. The protein accumulates in the nucleus in G2 and is mobilized onto the spindle pole bodies and spindle midzone at anaphase onset, where it persists into midanaphase. Association with Pds1 occurs during S phase and is required for efficient nuclear targeting of Esp1. Spindle association is not fully restored in pds1 mutants expressing an Esp1-nuclear localization sequence fusion protein, suggesting that Pds1 is also required to promote Esp1 spindle binding. In agreement, Pds1 interacts with the spindle at the metaphase–anaphase transition and a fraction remains at the spindle pole bodies and the spindle midzone in anaphase cells. Finally, mutational analysis reveals that the conserved COOH-terminal region of Esp1 is important for spindle interaction.