Center for Biological Clocks Research, Department of Biology, Texas A&M University, College Station, 77843-3258, USA.
Cell. 2010 Feb 19;140(4):529-39. doi: 10.1016/j.cell.2009.12.042.
A circadian clock coordinates physiology and behavior in diverse groups of living organisms. Another major cyclic cellular event, the cell cycle, is regulated by the circadian clock in the few cases where linkage of these cycles has been studied. In the cyanobacterium Synechococcus elongatus, the circadian clock gates cell division by an unknown mechanism. Using timelapse microscopy, we confirm the gating of cell division in the wild-type and demonstrate the regulation of cytokinesis by key clock components. Specifically, a state of the oscillator protein KaiC that is associated with elevated ATPase activity closes the gate by acting through a known clock output pathway to inhibit FtsZ ring formation at the division site. An activity that stimulates KaiC phosphorylation independently of the KaiA protein was also uncovered. We propose a model that separates the functions of KaiC ATPase and phosphorylation in cell division gating and other circadian behaviors.
生物钟协调着不同生物群体的生理和行为。另一个主要的周期性细胞事件是细胞周期，在已经研究过这些周期联系的少数情况下，细胞周期受生物钟调控。在蓝藻聚球藻中，生物钟通过未知机制控制细胞分裂。通过延时显微镜，我们确认了野生型中的细胞分裂门控，并证明了关键生物钟成分对胞质分裂的调节。具体来说，与高 ATPase 活性相关的振荡器蛋白 KaiC 的一种状态通过作用于已知的时钟输出途径来关闭门控，从而抑制分裂部位 FtsZ 环的形成。还发现了一种独立于 KaiA 蛋白刺激 KaiC 磷酸化的活性。我们提出了一个模型，将 KaiC ATPase 和磷酸化在细胞分裂门控和其他生物钟行为中的功能分开。
