Roles of polo-like kinase 1 in the assembly of functional mitotic spindles
Roles of polo-like kinase 1 in the assembly of functional mitotic spindles
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DOI：
10.1016/j.cub.2004.09.049
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发表时间：
2004-10-05
期刊：
影响因子：
9.2
通讯作者：
Peters, JM
中科院分区：
文献类型：
--
作者：
Sumara, I;Giménez-Abián, JF;Peters, JM
背景：染色体与有丝分裂纺锤体两极的稳定结合（双向定向）依赖于纺锤体的牵拉力。这些力在姐妹动粒之间产生张力，并被认为可稳定微管 - 动粒相互作用以及使纺锤体检查点沉默。波罗蛋白样激酶1（Plk1）涉及调节中心体成熟、有丝分裂进入、姐妹染色单体粘连、后期促进复合物/周期体（APC/C）以及胞质分裂，但Plk1是否控制染色体双向定向尚不清楚。
结果：我们通过RNA干扰（RNAi）分析了Plk1在同步化哺乳动物细胞中的功能。Plk1缺失的细胞在短暂延迟后进入有丝分裂，在前后期状态积累，随后常常因凋亡而死亡。Plk1缺失细胞中的纺锤体缺乏集中的极，且与中心体无关联。染色体附着在这些纺锤体上，但检查点蛋白Mad2、BubR1和CENP - E在许多动粒处富集。当用极光B抑制剂赫斯珀拉丁处理Plk1缺失的细胞时，该抑制剂通过稳定微管 - 动粒相互作用使纺锤体检查点沉默，细胞降解APC/C底物并在没有染色体分离和胞质分裂的情况下退出有丝分裂。用驱动蛋白抑制剂莫纳斯托尔诱导单极纺锤体的实验表明，Plk1是能够产生向极牵拉力的纺锤体组装所必需的。
结论：我们的结果表明，Plk1对于有丝分裂进入和APC/C激活不是必需的，但对于正常的纺锤体组装和功能是必需的。在Plk1缺失的细胞中，纺锤体可能无法在姐妹动粒之间产生足够的张力以稳定微管 - 动粒相互作用并使纺锤体检查点沉默。
Background: The stable association of chromosomes with both poles of the mitotic spindle (biorientation) depends on spindle pulling forces. These forces create tension across sister kinetochores and are thought to stabilize microtubule-kinetochore interactions and to silence the spindle checkpoint. Polo-like kinase 1 (Plk1) has been implicated in regulating centrosome maturation, mitotic entry, sister chromatid cohesion, the anaphase-promoting complex/cyclosome (APC/C), and cytokinesis, but it is unknown if Plk1 controls chromosome biorientation.Results: We have analyzed Plk1 functions in synchronized mammalian cells by RNA interference (RNAi). Plk1 depleted cells enter mitosis after a short delay, accumulate in a preanaphase state, and subsequently often die by apoptosis. Spindles in Plk1-depleted cells lack focused poles and are not associated with centrosomes. Chromosomes attach to these spindles, but the checkpoint proteins Mad2, BubR1, and CENP-E are enriched at many kinetochores. When Plk1-depleted cells are treated with the Aurora B inhibitor Hesperadin, which silences the spindle checkpoint by stabilizing microtubule-kinetochore interactions, cells degrade APC/C substrates and exit mitosis without chromosome segregation and cytokinesis. Experiments with monopolar spindles that are induced by the kinesin inhibitor Monastrol indicate that Plk1 is required for the assembly of spindles that are able to generate poleward pulling forces.Conclusions: Our results imply that Plk1 is not essential for mitotic entry and APC/C activation but is required for proper spindle assembly and function. In Plk1-depleted cells spindles may not be able to create enough tension across sister kinetochores to stabilize microtubule-kinetochore interactions and to silence the spindle checkpoint.