The Plant-Specific Kinase CDKF;1 Is Involved in Activating Phosphorylation of Cyclin-Dependent Kinase-Activating Kinases in Arabidopsis
The Plant-Specific Kinase CDKF;1 Is Involved in Activating Phosphorylation of Cyclin-Dependent Kinase-Activating Kinases in Arabidopsis
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DOI：
10.1105/tpc.104.025601
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发表时间：
2004-11
期刊：
影响因子：
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通讯作者：
Akie Shimotohno;C. Umeda-Hara;K. Bišová;H. Uchimiya;M. Umeda
中科院分区：
文献类型：
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作者：
Akie Shimotohno;C. Umeda-Hara;K. Bišová;H. Uchimiya;M. Umeda
细胞周期蛋白依赖性激酶（CDKs）在协调控制细胞周期进程中发挥重要作用。CDK的激活需要与特定的细胞周期蛋白伴侣相互作用，并通过CDK激活激酶（CAK）磷酸化其T环。拟南芥基因组编码四种潜在的CAK。CAK2At（CDKD; 3）和CAK 4At（CDKD; 2）与脊椎动物CAK（CDK 7/p40 MO 15）密切相关;它们与细胞周期蛋白H相互作用并磷酸化CDK，以及RNA聚合酶II的最大亚基的C-末端结构域（CTD）。CAK 1At（CDKF;1）显示细胞周期蛋白H非依赖性CDK-激酶活性，并且可以激活裂殖酵母中的异源CAK，Mcs 6。在拟南芥中，CAK 1At是130 kD蛋白复合物的亚基，其在体外和根原生质体中磷酸化CAK 2At和CAK 4At的T环并激活CAK 4At的CTD激酶活性。这些结果表明，CAK 1At是一个新的CAK激活激酶，调节CAK 2At和CAK 4At的活性，从而控制CDK活性和基础转录在拟南芥。
Cyclin-dependent kinases (CDKs) play essential roles in coordinate control of cell cycle progression. Activation of CDKs requires interaction with specific cyclin partners and phosphorylation of their T-loops by CDK-activating kinases (CAKs). The Arabidopsis thaliana genome encodes four potential CAKs. CAK2At (CDKD;3) and CAK4At (CDKD;2) are closely related to the vertebrate CAK, CDK7/p40MO15; they interact with cyclin H and phosphorylate CDKs, as well as the C-terminal domain (CTD) of the largest subunit of RNA polymerase II. CAK1At (CDKF;1) shows cyclin H-independent CDK-kinase activity and can activate a heterologous CAK, Mcs6, in fission yeast. In Arabidopsis, CAK1At is a subunit of a protein complex of 130 kD, which phosphorylates the T-loop of CAK2At and CAK4At and activates the CTD-kinase activity of CAK4At in vitro and in root protoplasts. These results suggest that CAK1At is a novel CAK-activating kinase that modulates the activity of CAK2At and CAK4At, thereby controlling CDK activities and basal transcription in Arabidopsis.