A large-scale functional RNAi screen reveals a role for CK2 in the mammalian circadian clock
A large-scale functional RNAi screen reveals a role for CK2 in the mammalian circadian clock
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DOI：
10.1101/gad.512209
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发表时间：
2009-03-15
影响因子：
10.5
通讯作者：
Kramer, Achim
中科院分区：
文献类型：
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作者：
Maier, Bert;Wendt, Sabrina;Kramer, Achim
翻译后过程对于哺乳动物昼夜节律的产生和动态至关重要。特别是，关键昼夜节律蛋白 PER2 的磷酸化精确控制昼夜节律振荡的周期和相位。然而，人们对这种控制背后的机制知之甚少。在这里，我们在基于高通量 RNAi 的遗传筛选中鉴定出酪蛋白激酶 2 (CK2) 作为 PER2 磷酸化激酶和哺乳动物生物钟的新组成部分。当 CK2 亚基被 RNAi 沉默或当 CK2 活性受到药物抑制时，昼夜节律就会被扰乱。 CK2 在体内与 PER2 结合，在体外特异性磷酸化 PER2 N 端残基，并支持正常的细胞核 PER2 积累。 CK2 磷酸化位点的突变会降低 PER2 稳定性并复制有关振荡动力学的 CK2 抑制。我们提出了一个新概念，即 PER2 磷酸化和稳定化如何根据作用阶段将时钟速度设置为相反方向。
Post-translational processes are essential for the generation and dynamics of mammalian circadian rhythms. In particular, phosphorylation of the key circadian protein PER2 precisely controls the period and phase of circadian oscillations. However, the mechanisms underlying that control are poorly understood. Here, we identified in a high-throughput RNAi-based genetic screen casein kinase 2 (CK2) as a PER2-phosphorylating kinase and novel component of the mammalian circadian clock. When CK2 subunits are silenced by RNAi or when CK2 activity is inhibited pharmacologically, circadian rhythms are disrupted. CK2 binds to PER2 in vivo, phosphorylates PER2 specifically at N-terminal residues in vitro, and supports normal nuclear PER2 accumulation. Mutation of CK2 phosphorylation sites decreases PER2 stability and copies CK2 inhibition regarding oscillation dynamics. We propose a new concept of how PER2 phosphorylation and stabilization can set the clock speed in opposite directions, dependent on the phase of action.