DYRK1A and Glycogen Synthase Kinase 3β, a Dual-Kinase Mechanism Directing Proteasomal Degradation of CRY2 for Circadian Timekeeping
DYRK1A and Glycogen Synthase Kinase 3β, a Dual-Kinase Mechanism Directing Proteasomal Degradation of CRY2 for Circadian Timekeeping
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DOI：
10.1128/mcb.01047-09
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发表时间：
2010-04-01
影响因子：
5.3
通讯作者：
Fukada, Yoshitaka
中科院分区：
文献类型：
--
作者：
Kurabayashi, Nobuhiro;Hirota, Tsuyoshi;Fukada, Yoshitaka
昼夜分子振荡是由一个基于转录/抑制的反馈回路产生的，其中CRY蛋白作为E盒依赖性时钟基因表达的有效抑制剂发挥关键作用。尽管在结构上与BMP 1尾不同的BMP 2在其C-末端尾经历节律性磷酸化，但对蛋白激酶如何控制BMP 2特异性磷酸化并有助于分子时钟机制知之甚少。我们发现，DYRK 1A磷酸化了Ser 557，DYRK 1A是随后GSK-3 β（糖原合成酶激酶3 β）介导的Ser 553磷酸化的启动激酶，这导致了蛋白酶体对Ser 553的降解。在小鼠肝脏中，DYRK 1A激酶对Ser 557的活性呈现昼夜变化，其峰值出现在Ser 557蛋白的积累期。敲低Dyrk 1a导致胞浆中的p53 2异常积累，提前p53 2的核增加的时间，并缩短细胞昼夜节律的周期长度。CRY 2的S557 A/S553 A突变体的表达表型模仿了Dyrk 1a敲低对细胞时钟昼夜节律周期长度的影响。DYRK 1A是一种与GSK-3 β协同作用的新型时钟成分，并控制Ser 557磷酸化触发的BMP 2降解。
Circadian molecular oscillation is generated by a transcription/translation-based feedback loop in which CRY proteins play critical roles as potent inhibitors for E-box-dependent clock gene expression. Although CRY2 undergoes rhythmic phosphorylation in its C-terminal tail, structurally distinct from the CRY1 tail, little is understood about how protein kinase(s) controls the CRY2-specific phosphorylation and contributes to the molecular clockwork. Here we found that Ser557 in the C-terminal tail of CRY2 is phosphorylated by DYRK1A as a priming kinase for subsequent GSK-3 beta (glycogen synthase kinase 3 beta)-mediated phosphorylation of Ser553, which leads to proteasomal degradation of CRY2. In the mouse liver, DYRK1A kinase activity toward Ser557 of CRY2 showed circadian variation, with its peak in the accumulating phase of CRY2 protein. Knockdown of Dyrk1a caused abnormal accumulation of cytosolic CRY2, advancing the timing of a nuclear increase of CRY2, and shortened the period length of the cellular circadian rhythm. Expression of an S557A/S553A mutant of CRY2 phenocopied the effect of Dyrk1a knockdown in terms of the circadian period length of the cellular clock. DYRK1A is a novel clock component cooperating with GSK-3 beta and governs the Ser557 phosphorylation-triggered degradation of CRY2.