Dynamics of the circadian clock protein PERIOD2 in living cells
Dynamics of the circadian clock protein PERIOD2 in living cells
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DOI：
10.1242/jcs.156612
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发表时间：
2014-10-01
影响因子：
4
通讯作者：
Kramer, Achim
中科院分区：
文献类型：
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作者：
Oellinger, Rupert;Korge, Sandra;Kramer, Achim
在哺乳动物中，昼夜节律是通过延迟负反馈产生的，其中周期（PER1-PER3）和隐花色素（CRY1、CRY2）蛋白逐渐在细胞核中积累，以抑制自身基因的转录。尽管核输入和输出信号对于时钟蛋白亚细胞定位的重要性已得到充分证实，但人们对这些过程的动力学及其对昼夜节律产生的重要性知之甚少。我们通过振荡细胞的药理扰动表明，核输入和输出对于昼夜节律至关重要。活细胞荧光显微镜显示，关键昼夜节律蛋白 PER2 的核输入速度很快，并被 CRY1 进一步加速。此外，PER2 核输入主要依赖于 PER2 中特定的核受体结合基序，该基序也介导核固定性。然而，核输出相对较慢，支持快速输入、缓慢输出和大量核退化的 PER2 核积累模型。
In mammals, circadian rhythms are generated by delayed negative feedback, in which period (PER1-PER3) and cryptochrome (CRY1, CRY2) proteins gradually accumulate in the nucleus to suppress the transcription of their own genes. Although the importance of nuclear import and export signals for the subcellular localization of clock proteins is well established, little is known about the dynamics of these processes as well as their importance for the generation of circadian rhythms. We show by pharmacological perturbations of oscillating cells that nuclear import and export are of crucial importance for the circadian period. Live-cell fluorescence microscopy revealed that nuclear import of the key circadian protein PER2 is fast and further accelerated by CRY1. Moreover, PER2 nuclear import is crucially dependent on a specific nuclear-receptor-binding motif in PER2 that also mediates nuclear immobility. Nuclear export, however, is relatively slow, supporting a model of PER2 nuclear accumulation by rapid import, slow export and substantial nuclear degradation.