CK2 phosphorylation of CCA1 is necessary for its circadian oscillator function in Arabidopsis
CK2 phosphorylation of CCA1 is necessary for its circadian oscillator function in Arabidopsis
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DOI：
10.1073/pnas.0400163101
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发表时间：
2004-03-02
影响因子：
11.1
通讯作者：
Tobin, EM
中科院分区：
文献类型：
--
作者：
Daniel, X;Sugano, S;Tobin, EM
生物钟控制着从真菌到人类等生物体的许多生理和分子过程。在植物中，这些过程包括叶片运动、气孔打开和大量基因的表达。在生物钟的核心，中央振荡器由一个与日常环境变化相协调的负自我调节反馈回路组成，并产生显性过程的昼夜节律。一些中心振荡蛋白的磷酸化对于果蝇、人类和神经孢子虫的正常昼夜节律的产生是必要的，其中CK1和CK2正成为参与PER和FRQ磷酸化的主要蛋白激酶。我们之前已经证明，在拟南芥中，蛋白激酶CK2可以体外磷酸化生物钟相关蛋白昼夜节律钟相关蛋白1 （CIRCADIAN CLOCK ASSOCIATED 1, CCA1）。其调控亚基之一CKB3的过表达影响昼夜节律的调节。CK2对生物钟的影响是否由于其对生物钟成分的磷酸化而尚未得到证实。通过检测组成性表达不能被CK2磷酸化的拟南芥时钟蛋白CCA1突变体的影响，我们在这里证明了CCA1被CK2磷酸化对中心振荡器的正常功能是重要的。
The circadian clock controls numerous physiological and molecular processes in organisms ranging from fungi to human. In plants, these processes include leaf movement, stomata opening, and expression of a large number of genes. At the core of the circadian clock, the central oscillator consists of a negative autoregulatory feedback loop that is coordinated with the daily environmental changes, and that generates the circadian rhythms of the overt processes. Phosphorylation of some of the central oscillator proteins is necessary for the generation of normal circadian rhythms of Drosophila, humans, and Neurospora, where CK1 and CK2 are emerging as the main protein kinases involved in the phosphorylation of PER and FRQ. We have previously shown that in Arabidopsis, the protein kinase CK2 can phosphorylate the clock-associated protein CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) in vitro. The overexpression of one of its regulatory subunits, CKB3, affects the regulation of circadian rhythms. Whether the effects of CK2 on the clock were due to its phosphorylation of a clock component had yet to be proven. By examining the effects of constitutively expressing a mutant form of the Arabidopsis clock protein CCA1 that cannot be phosphorylated by CK2, we demonstrate here that CCA1 phosphorylation by CK2 is important for the normal functioning of the central oscillator.