Characterization of spindle checkpoint kinase Mps1 reveals domain with functional and structural similarities to tetratricopeptide repeat motifs of Bub1 and BubR1 checkpoint kinases.
Characterization of spindle checkpoint kinase Mps1 reveals domain with functional and structural similarities to tetratricopeptide repeat motifs of Bub1 and BubR1 checkpoint kinases.
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DOI：
10.1074/jbc.m111.307355
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发表时间：
2012-02-17
期刊：
影响因子：
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通讯作者：
Elowe S
中科院分区：
文献类型：
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作者：
Lee S;Thebault P;Freschi L;Beaufils S;Blundell TL;Landry CR;Bolanos-Garcia VM;Elowe S
背景：N端是Mps 1、Bub 1和BubR 1激酶定位和功能所必需的。结果：在Mps 1中发现了一个新的Bub 1/BubR 1相关TPR基序，该基序是激酶活性所必需的。结论：Mps 1的TPR结构域调节激酶活性、Mps 1染色体排列和检查点功能。意义：Mps 1中一个新结构域的鉴定增强了我们对其维持基因组完整性的贡献的理解。有丝分裂激酶Bub 1、BubR 1和Mps 1的动粒靶向作用与它们在纺锤体检查点中的功能的有效执行有关，纺锤体检查点是真核细胞周期的自我监测系统，其确保染色体分离以高保真度发生。在所有三种激酶中，动粒对接由蛋白质的N-末端区域介导。该区域内的缺失导致检查点失败和染色体分离缺陷。在这里，我们使用跨学科的方法，包括生物物理学，生物化学，细胞生物学和生物信息学的方法来研究人类Mps 1的N-末端区域。我们报告的四个三肽重复（TPR）基序的N-末端动粒结合区的Mps 1，与Bub 1和BubR 1的串联TPR基序的同源性密切的串联重复的鉴定。系统发育分析表明，TPR Mps 1是在后口动物和原口动物之间分裂后获得的，因为它在脊索动物和棘皮动物中是可区分的。TPR Mps 1的过表达导致染色体排列和有丝分裂停滞的效率降低，可能是通过从动粒置换内源性Mps 1和降低Mps 1催化活性。总之，我们的多学科战略提供了新的见解Mps 1 N-末端区域的演变，结构组织和功能。
Background: The N terminus is required for localization and functions of Mps1, Bub1, and BubR1 kinases. Results: A novel Bub1/BubR1-related TPR motif is identified in Mps1 and is required for kinase activity. Conclusion: TPR domain of Mps1 regulates kinase activity, Mps1 chromosome alignment, and checkpoint functions. Significance: Identification of a novel domain in Mps1 enhances our understanding of its contribution to maintaining genome integrity. Kinetochore targeting of the mitotic kinases Bub1, BubR1, and Mps1 has been implicated in efficient execution of their functions in the spindle checkpoint, the self-monitoring system of the eukaryotic cell cycle that ensures chromosome segregation occurs with high fidelity. In all three kinases, kinetochore docking is mediated by the N-terminal region of the protein. Deletions within this region result in checkpoint failure and chromosome segregation defects. Here, we use an interdisciplinary approach that includes biophysical, biochemical, cell biological, and bioinformatics methods to study the N-terminal region of human Mps1. We report the identification of a tandem repeat of the tetratricopeptide repeat (TPR) motif in the N-terminal kinetochore binding region of Mps1, with close homology to the tandem TPR motif of Bub1 and BubR1. Phylogenetic analysis indicates that TPR Mps1 was acquired after the split between deutorostomes and protostomes, as it is distinguishable in chordates and echinoderms. Overexpression of TPR Mps1 resulted in decreased efficiency of both chromosome alignment and mitotic arrest, likely through displacement of endogenous Mps1 from the kinetochore and decreased Mps1 catalytic activity. Taken together, our multidisciplinary strategy provides new insights into the evolution, structural organization, and function of Mps1 N-terminal region.