Cell cycle regulation of the activity and subcellular localization of Plk1, a human protein kinase implicated in mitotic spindle function.
Cell cycle regulation of the activity and subcellular localization of Plk1, a human protein kinase implicated in mitotic spindle function.
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DOI：
10.1083/jcb.129.6.1617
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发表时间：
1995-06
期刊：
影响因子：
--
通讯作者：
Nigg EA
中科院分区：
文献类型：
--
作者：
Golsteyn RM;Mundt KE;Fry AM;Nigg EA
细胞分裂过程中有丝分裂主轴的正确组装和功能对于将重复的基因组准确分配到子细胞中至关重要。长期以来，蛋白质磷酸化一直与控制纺锤体功能和染色体分离有关，遗传研究已经鉴定出可能调节这些过程的几种蛋白激酶和磷酸酶。特别是，丝氨酸/苏氨酸特异性果蝇激酶马球的突变以及酿酒酵母的结构相关的激酶CDC5P导致异常有丝分裂和减数分裂分裂。在这里，我们描述了PLK1的细胞周期依赖性活性和亚细胞定位的详细分析，PLK1是一种最近鉴定出的人类蛋白激酶，与果蝇和酿酒酵母Cdc5p具有广泛的序列相似性。借助重组杆菌病毒，我们为PLK1激酶活性建立了可靠的体外测定法。我们表明，人PLK1的活性是细胞周期调节，PLK1在相间期间的活性较低，但在有丝分裂过程中很高。通过免疫荧光共聚焦激光扫描显微镜进一步表明，人PLK1在有丝分裂的所有阶段与有丝分裂纺锤体的成分结合，但随着细胞从中期从中期发展到后期，经过引人注目的重新分布。具体而言，PLK1与主轴杆相连到中期，但重新定位到赤道平面，当细胞穿过后期时，纺锤微管重叠（MIDZONE）的赤道平面。这些结果表明，PLK1与纺锤体的关联是高度动态的，PLK1可能在有丝分裂进程的多个阶段起作用。综上所述，我们的数据加强了人类PLK1可能代表Polo和Cdc5p的功能同源物的观念，他们认为这种激酶在染色体分离过程中有丝分裂纺锤体的动态功能中起重要作用。
Correct assembly and function of the mitotic spindle during cell division is essential for the accurate partitioning of the duplicated genome to daughter cells. Protein phosphorylation has long been implicated in controlling spindle function and chromosome segregation, and genetic studies have identified several protein kinases and phosphatases that are likely to regulate these processes. In particular, mutations in the serine/threonine-specific Drosophila kinase polo, and the structurally related kinase Cdc5p of Saccharomyces cerevisae, result in abnormal mitotic and meiotic divisions. Here, we describe a detailed analysis of the cell cycle-dependent activity and subcellular localization of Plk1, a recently identified human protein kinase with extensive sequence similarity to both Drosophila polo and S. cerevisiae Cdc5p. With the aid of recombinant baculoviruses, we have established a reliable in vitro assay for Plk1 kinase activity. We show that the activity of human Plk1 is cell cycle regulated, Plk1 activity being low during interphase but high during mitosis. We further show, by immunofluorescent confocal laser scanning microscopy, that human Plk1 binds to components of the mitotic spindle at all stages of mitosis, but undergoes a striking redistribution as cells progress from metaphase to anaphase. Specifically, Plk1 associates with spindle poles up to metaphase, but relocalizes to the equatorial plane, where spindle microtubules overlap (the midzone), as cells go through anaphase. These results indicate that the association of Plk1 with the spindle is highly dynamic and that Plk1 may function at multiple stages of mitotic progression. Taken together, our data strengthen the notion that human Plk1 may represent a functional homolog of polo and Cdc5p, and they suggest that this kinase plays an important role in the dynamic function of the mitotic spindle during chromosome segregation.