Laboratory of Genetics, The Rockefeller University, New York, United States.
Department of Chemistry and Chemical Biology, Cornell University, New York, United States.
Elife. 2018 Apr 3;7:e32679. doi: 10.7554/eLife.32679.
In the circadian clock, Period (PER) and Timeless (TIM) proteins inhibit Clock-mediated transcription of and genes until PER is degraded by Doubletime/CK1 (DBT)-mediated phosphorylation, establishing a negative feedback loop. Multiple regulatory delays within this feedback loop ensure ~24 hr periodicity. Of these delays, the mechanisms that regulate delayed PER degradation (and Clock reactivation) remain unclear. Here we show that phosphorylation of certain DBT target sites within a central region of PER affect PER inhibition of Clock and the stability of the PER/TIM complex. Our results indicate that phosphorylation of PER residue S589 stabilizes and activates PER inhibitory function in the presence of TIM, but promotes PER degradation in its absence. The role of DBT in regulating PER activity, stabilization and degradation ensures that these events are chronologically and biochemically linked, and contributes to the timing of an essential delay that influences the period of the circadian clock.
在生物钟中，PER 和 TIM 蛋白抑制 Clock 介导的 和 基因的转录，直到 PER 被 DBT/CK1（DBT）介导的磷酸化降解，建立一个负反馈回路。这个反馈回路中的多个调节延迟确保了大约 24 小时的周期性。在这些延迟中，调节延迟 PER 降解（和 Clock 再激活）的机制尚不清楚。在这里，我们表明，PER 中一个中央区域的某些 DBT 靶标位点的磷酸化影响 PER 对 Clock 的抑制作用和 PER/TIM 复合物的稳定性。我们的结果表明，PER 残基 S589 的磷酸化在 TIM 存在的情况下稳定并激活了 PER 的抑制功能，但在 TIM 不存在的情况下促进了 PER 的降解。DBT 在调节 PER 活性、稳定性和降解中的作用确保了这些事件在时间上和生化上是相互关联的，并有助于影响生物钟周期的一个重要延迟的定时。
