Autonomous synchronization of the circadian KaiC phosphorylation rhythm
Autonomous synchronization of the circadian KaiC phosphorylation rhythm
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DOI：
10.1038/nsmb1312
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发表时间：
2007-11-01
影响因子：
16.8
通讯作者：
Kondo, Takao
中科院分区：
文献类型：
--
作者：
Ito, Hiroshi;Kageyama, Hakuto;Kondo, Takao
通过将三种纯化的时钟蛋白KaiA、KaiB和KaiC与ATP混合，可以在体外重建蓝藻昼夜节律振荡器。KaiC磷酸化节律持续至少10天而没有衰减。通过混合具有不同相位的振荡样品并分析其相位关系的动力学，我们发现KaiC磷酸化节律的鲁棒性来自KaiC蛋白的磷酸化状态和反应方向（磷酸化或去磷酸化）的快速同步。我们进一步证明了同步化与KaiC去磷酸化密切相关，并且在早期去磷酸化阶段由KaiC六聚体之间的单体交换介导。这种自主同步机制可能是蓝藻昼夜节律系统的弹性的基础上，对定量波动的时钟组件在细胞事件，如细胞生长和分裂。
The cyanobacterial circadian oscillator can be reconstituted in vitro by mixing three purified clock proteins, KaiA, KaiB and KaiC, with ATP. The KaiC phosphorylation rhythm persists for at least 10 days without damping. By mixing oscillatory samples that have different phases and analyzing the dynamics of their phase relationships, we found that the robustness of the KaiC phosphorylation rhythm arises from the rapid synchronization of the phosphorylation state and reaction direction ( phosphorylation or dephosphorylation) of KaiC proteins. We further demonstrate that synchronization is tightly linked with KaiC dephosphorylation and is mediated by monomer exchange between KaiC hexamers during the early dephosphorylation phase. This autonomous synchronization mechanism is probably the basis for the resilience of the cyanobacterial circadian system against quantitative fluctuations in clock components during cellular events such as cell growth and division.