Yeast Fin1-PP1 dephosphorylates an Ipl1 substrate, Ndc80, to remove Bub1-Bub3 checkpoint proteins from the kinetochore during anaphase.
Yeast Fin1-PP1 dephosphorylates an Ipl1 substrate, Ndc80, to remove Bub1-Bub3 checkpoint proteins from the kinetochore during anaphase.
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DOI：
10.1371/journal.pgen.1009592
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发表时间：
2021-05
期刊：
影响因子：
4.5
通讯作者：
Wang Y
中科院分区：
文献类型：
--
作者：
Bokros M;Sherwin D;Kabbaj MH;Wang Y
纺锤体组装检查点(SAC)防止对染色体附着缺陷的后期启动，而SAC沉默是后期启动所必需的。在细胞分裂后期开始后，激活的CDC14磷酸酶使细胞周期蛋白依赖的激酶底物去磷酸化，以促进后期进程和有丝分裂的退出。在萌芽酵母中，CDC14使蛋白磷酸酶1(PP1)的一个调节亚基Fin1去磷酸化，使Fin1-PP1的动粒定位成为可能。我们先前已经证明，动粒定位的Fin1-PP1在动粒后期促进SAC蛋白Bub1从动粒中移除。我们在这里报道，Fin1-PP1也促进Bub1伙伴Bub3的动粒去除，但对另一种SAC蛋白Mad1没有影响。此外，Bub1-Bub3在后期的动粒定位需要Aurora B/Ipl1激酶的活性。我们进一步证明Fin1-PP1促进动粒蛋白Ndc80的去磷酸化，动粒蛋白Ndc80是一种已知的Ipl1底物。这种去磷酸化减少了后期Bub1-Bub3的动粒结合。此外，我们发现过早的Ndc80去磷酸化会导致活性丧失，以响应无张力的染色体附着。这些结果表明，Fin1-PP1及时定位于着丝粒，控制着SAC的功能窗口，因此对于忠实的染色体分离是至关重要的。染色体附着中的错误激活了纺锤体组件检查点，以停止细胞周期以进行纠错。这种激活依赖于检查点蛋白的动粒招募，包括Bub1-Bub3复合体。在细胞建立染色体双极连接后，纺锤体组装检查点被蛋白磷酸酶1(PP1)沉默，以允许后期进入。Fin1是发芽酵母中PP1的一个调节亚基，当纺锤体组装检查点沉默时，Fin1在后期将PP1招募到动粒中。我们先前证明Fin1-PP1促进检查点蛋白Bub1在后期从着丝粒中解离，揭示了在其沉默后对纺锤体组装检查点的意外调节。在这里，我们证明了Fin1-PP1在后期促进了Bub1和Bub3的动粒解离，并且Bub1和Bub3的动粒结合是相互依赖的。研究表明，PP1拮抗Ipl1/Aurora B的磷酸化，Ipl1/Aurora B是一种保守的蛋白激酶，对准确的染色体分离至关重要。我们进一步发现，Fin1-PP1促进动粒蛋白Ndc80的去磷酸化，这是Ipl1底物，从而减少Bub1-Bub3的动粒结合。此外，Ndc80磷酸化的失调导致在诱导联觉依附时增加了存活率损失。因此，我们确定了纺锤体组装检查点在细胞后期的一层新的调控层，以确保其在细胞周期中的功能窗口。
The spindle assembly checkpoint (SAC) prevents anaphase onset in response to chromosome attachment defects, and SAC silencing is essential for anaphase onset. Following anaphase onset, activated Cdc14 phosphatase dephosphorylates the substrates of cyclin-dependent kinase to facilitate anaphase progression and mitotic exit. In budding yeast, Cdc14 dephosphorylates Fin1, a regulatory subunit of protein phosphatase 1 (PP1), to enable kinetochore localization of Fin1-PP1. We previously showed that kinetochore-localized Fin1-PP1 promotes the removal of the SAC protein Bub1 from the kinetochore during anaphase. We report here that Fin1-PP1 also promotes kinetochore removal of Bub3, the Bub1 partner, but has no effect on another SAC protein Mad1. Moreover, the kinetochore localization of Bub1-Bub3 during anaphase requires Aurora B/Ipl1 kinase activity. We further showed that Fin1-PP1 facilitates the dephosphorylation of kinetochore protein Ndc80, a known Ipl1 substrate. This dephosphorylation reduces kinetochore association of Bub1-Bub3 during anaphase. In addition, we found that untimely Ndc80 dephosphorylation causes viability loss in response to tensionless chromosome attachments. These results suggest that timely localization of Fin1-PP1 to the kinetochore controls the functional window of SAC and is therefore critical for faithful chromosome segregation. Mistakes in chromosome attachment activate the spindle assembly checkpoint to stop the cell cycle for error correction. This activation depends on kinetochore recruitment of checkpoint proteins, including the Bub1-Bub3 complex. After cells have established chromosome bipolar attachment, the spindle assembly checkpoint is silenced by protein phosphatase 1 (PP1) to enable anaphase entry. Fin1 is a regulatory subunit of PP1 in budding yeast, and Fin1 recruits PP1 to the kinetochore during anaphase when the spindle assembly checkpoint is silenced. We previously showed that Fin1-PP1 promotes the dissociation of checkpoint protein Bub1 from the kinetochore during anaphase, revealing an unexpected regulation of the spindle assembly checkpoint after its silencing. Here, we showed that Fin1-PP1 promotes the kinetochore dissociation of both Bub1 and Bub3 during anaphase, and that the kinetochore association of Bub1 and Bub3 is interdependent. It has been shown that PP1 antagonizes the phosphorylation imposed by Ipl1/Aurora B, a conserved protein kinase critical for accurate chromosome segregation. We further found that Fin1-PP1 promotes the dephosphorylation of kinetochore protein Ndc80, an Ipl1 substrate, which reduces kinetochore association of Bub1-Bub3. Moreover, dysregulation of Ndc80 phosphorylation results in increased viability loss when syntelic attachment is induced. Therefore, we identified a new layer of regulation of the spindle assembly checkpoint during anaphase, which ensures its functional window during cell cycle.
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影响因子：
8.8
作者：
Bokros M;Gravenmier C;Jin F;Richmond D;Wang Y
通讯作者：
Wang Y
影响因子：
10.5
作者：
CohenFix, O;Peters, JM;Koshland, D
通讯作者：
Koshland, D
影响因子：
5.3
作者：
Baetz, KK;Krogan, NJ;Hieter, P
通讯作者：
Hieter, P
影响因子：
7.8
作者：
Dhatchinamoorthy, Karthik;Unruh, Jay R.;Gerton, Jennifer L.
通讯作者：
Gerton, Jennifer L.
DOI：
10.1083/jcb.145.7.1381
发表时间：
1999-06-28
期刊：
The Journal of cell biology
影响因子：
--
作者：
Kim JH;Kang JS;Chan CS
通讯作者：
Chan CS