Site-specific phosphorylation of casein kinase 1 δ (CK1δ) regulates its activity towards the circadian regulator PER2
Site-specific phosphorylation of casein kinase 1 δ (CK1δ) regulates its activity towards the circadian regulator PER2
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DOI：
10.1371/journal.pone.0177834
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发表时间：
2017-05-17
期刊：
影响因子：
3.7
通讯作者：
Virshup, David M.
中科院分区：
文献类型：
--
作者：
Eng, Gracie Wee Ling;Edison;Virshup, David M.
昼夜节律是内在的类似于24小时周期，调节生理学的各个方面，反过来又通过与外部环境的相互作用来调节。酪蛋白激酶1 δ (CK1 δ, CSNK1D)是生物钟的关键调节因子，在一种被称为磷酸化开关的机制中磷酸化PER2蛋白上的稳定位点和不稳定位点。CK1 delta本身可以通过其调控区域的磷酸化来调节，但所涉及的具体位点及其在控制昼夜节律和其他CK1依赖性过程中的作用尚不清楚。通过敏化PER2:: LUC报告基因分析，我们在CK1 δ上发现了一个特定的磷酸化位点T347，该位点调节CK1 δ对PER2的活性。突变体CK1 δ T347A在促进PER2降解方面更为活跃。在细胞中，这个CK1调控位点在反式中被dinaciclib和staurosporine敏感激酶磷酸化，与细胞周期蛋白依赖性激酶和其他脯氨酸定向激酶的潜在调控一致。通过细胞周期和其他信号通路的位点特异性磷酸化对CK1 δ的调节提供了一种机制，将外部刺激偶联到包括生物钟在内的CK1 δ依赖通路的调节中。
Circadian rhythms are intrinsic similar to 24 hour cycles that regulate diverse aspects of physiology, and in turn are regulated by interactions with the external environment. Casein kinase 1 delta (CK1 delta, CSNK1D) is a key regulator of the clock, phosphorylating both stabilizing and destabilizing sites on the PER2 protein, in a mechanism known as the phosphoswitch. CK1 delta can itself be regulated by phosphorylation on its regulatory domain, but the specific sites involved, and the role this plays in control of circadian rhythms as well as other CK1-dependent processes is not well understood. Using a sensitized PER2:: LUC reporter assay, we identified a specific phosphorylation site, T347, on CK1 delta, that regulates CK1 delta activity towards PER2. A mutant CK1 delta T347A was more active in promoting PER2 degradation. This CK1 delta regulatory site is phosphorylated in cells in trans by dinaciclib- and staurosporine-sensitive kinases, consistent with their potential regulation by cyclin dependent and other proline-directed kinases. The regulation of CK1 delta by site-specific phosphorylation via the cell cycle and other signaling pathways provides a mechanism to couple external stimuli to regulation of CK1 delta-dependent pathways including the circadian clock.