Coordinated Reversal of Flagellar Motors on a Single Escherichia coli Cell
Coordinated Reversal of Flagellar Motors on a Single Escherichia coli Cell
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DOI：
10.1016/j.bpj.2011.03.030
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发表时间：
2011-05-04
影响因子：
3.4
通讯作者：
Ishijima, Akihiko
中科院分区：
文献类型：
--
作者：
Terasawa, Shun;Fukuoka, Hajime;Ishijima, Akihiko
大肠杆菌细胞将化学感受器感受到的细胞外刺激转换为细胞内信号分子的状态，其调节鞭毛马达的旋转方向从逆时针（CCW）到顺时针（CW）以及从CW回到CCW的切换。在这里，我们进行了高速成像的鞭毛电机旋转，并表明，切换两个不同的电机上的细胞是由细胞内的信号蛋白，磷酸化的CheY（CheY-P）协调控制。开关是高度协调的亚秒级的延迟电机之间的明确相关的距离，每个电机从化学感受器补丁定位在一个细胞的极点，这将被解释为扩散运动的CheY-P分子在细胞中。协调开关变得无序的组成型活性的CheY突变体，模仿CW旋转刺激功能的表达。协调开关需要CheZ，这是磷酸酶的CheY-P。我们的研究结果表明，一个瞬时的增加和减少，在浓度的CheY-P引起的自发爆发其生产的化学感受器补丁，然后由其去磷酸化的CheZ，这可能是一个波浪状的传播在亚秒的时间尺度，触发和调节鞭毛电机的协调开关。
An Escherichia coli cell transduces extracellular stimuli sensed by chemoreceptors to the state of an intracellular signal molecule, which regulates the switching of the rotational direction of the flagellar motors from counterclockwise (CCW) to clockwise (CW) and from CW back to CCW. Here, we performed high-speed imaging of flagellar motor rotation and show that the switching of two different motors on a cell is controlled coordinatedly by an intracellular signal protein, phosphorylated CheY (CheY-P). The switching is highly coordinated with a subsecond delay between motors in clear correlation with the distance of each motor from the chemoreceptor patch localized at a cell pole, which would be explained by the diffusive motion of CheY-P molecules in the cell. The coordinated switching becomes disordered by the expression of a constitutively active CheY mutant that mimics the CW-rotation stimulating function. The coordinated switching requires CheZ, which is the phosphatase for CheY-P. Our results suggest that a transient increase and decrease in the concentration of CheY-P caused by a spontaneous burst of its production by the chemoreceptor patch followed by its dephosphorylation by CheZ, which is probably a wavelike propagation in a subsecond timescale, triggers and regulates the coordinated switching of flagellar motors.