Dual Regulation of the Anaphase Promoting Complex in Human Cells by Cyclin A-Cdk2 and Cyclin A-Cdk1 Complexes
Dual Regulation of the Anaphase Promoting Complex in Human Cells by Cyclin A-Cdk2 and Cyclin A-Cdk1 Complexes
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DOI：
10.4161/cc.5.6.2604
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发表时间：
2006-02
期刊：
影响因子：
4.3
通讯作者：
J. Mitra;G. Enders;J. Azizkhan-Clifford;K. Lengel
中科院分区：
文献类型：
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作者：
J. Mitra;G. Enders;J. Azizkhan-Clifford;K. Lengel
在哺乳动物体细胞中，后期促进复合物（APC）在S期期间被活性细胞周期蛋白A-细胞周期蛋白依赖性激酶（Cdk）2复合物失活，所述复合物促进有丝分裂调节因子如细胞周期蛋白B和波罗样激酶1（Plk 1）的积累。然而，在Cdk 2 RNA干扰（i）或Cdk 2基因缺失后，在一些人类癌细胞或正常小鼠细胞中，有丝分裂进入似乎没有受到干扰。这些结果表明APC调节的功能互补的补偿激酶。使用Plk 1蛋白水平作为APC活性的读数，我们发现APC在人类细胞中的S期期间被细胞周期蛋白A-Cdk 2和细胞周期蛋白A-Cdk 1复合物灭活。Cdk 2或Cdk 2 RNAi的显性负突变体在早期S期的表达使Plk 1不稳定，因为它开始积累。然而，这种效应在S期后期减弱，其中Plk 1的不稳定也需要Cdk 1 RNAi。虽然Cdk 2是细胞周期蛋白A在这些设置中的主要合作伙伴，细胞周期蛋白A也结合Cdk 1。这两种复合物结合APC靶向因子Cdh 1，但Cdk 1复合物在早期S期无活性，这说明Cdk 2对APC功能的调节更强。这些结果提供了进一步的证据表明，细胞周期蛋白A-Cdk 2和-Cdk 1复合物显示重叠和部分冗余的作用，在准备细胞的有丝分裂，通过调节的APC。
In mammalian somatic cells, the Anaphase Promoting Complex (APC) is inactivated during S phase by active cyclin A-Cyclin dependent kinase (Cdk) 2 complexes promoting accumulation of mitotic regulators, such as cyclin B and Polo like kinase 1 (Plk1). However, mitotic entry does not appear to be perturbed in some human cancer cells or in normal mouse cells following Cdk2 RNA interference (i) or deletion of the Cdk2 gene. These results suggest functional complementation of APC regulation by a compensatory kinase. Using Plk1 protein level as readout of APC activity, we show that APC is inactivated during S phase in human cells by both cyclin A-Cdk2 and cyclin A-Cdk1 complexes. Expression of a dominant negative mutant of Cdk2 or Cdk2 RNAi in early S phase destabilizes Plk1 as it begins to accumulate. However, this effect wanes in late S phase, where destabilization of Plk1 also requires Cdk1 RNAi. Although Cdk2 is the dominant partner of cyclin A in these settings, cyclin A also binds Cdk1. Both complexes bind the APC targeting factor Cdh1, but Cdk1 complexes are inactive in early S phase, accounting for the stronger regulation of APC function by Cdk2. These results provide further evidence that cyclin A-Cdk2 and -Cdk1 complexes display overlapping and partially redundant roles in preparing cells for mitosis, through regulation of the APC.