Independence and interdependence of Dif and Frz chemosensory pathways in Myxococcus xanthus chemotaxis.
Independence and interdependence of Dif and Frz chemosensory pathways in Myxococcus xanthus chemotaxis.
复制标题
黄粘球菌趋化作用中 Dif 和 Frz 化学感应途径的独立性和相互依赖性。
DOI：
10.1111/j.1365-2958.2008.06322.x
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发表时间：
2008
影响因子：
3.6
通讯作者：
Yang,Zhaomin
中科院分区：
文献类型：
--
作者：
Xu,Qian;Black,WesleyP;Cadieux,CLinn;Yang,Zhaomin
在磷脂酰乙醇胺(PE)的趋化作用中，DIF和FRZ是两个黄色粘球菌化学感觉通路，分别用于激发和适应。在趋化作用和途径间相互作用的背景下，对这两个通路中接受甲基的化学受体的同系物DIFA和FrzCD进行了甲基化检测。有证据表明，DIFA可能不会发生甲基化，但通过DIFA传递的信号确实会调节FrzCD的甲基化。结果还表明，黄曲霉( xanthus)具有Dif依赖和Dif非依赖的PE敏感机制。以前的研究表明，负化学刺激降低了FrzCD甲基化，而PE等引诱剂则增加了该甲基化。这里的结果表明，依赖Dif的感觉机制抑制了引诱剂反应中FrzCD甲基化的增加，并在负刺激下提高了FrzCD甲基化。换句话说，FrzCD甲基化是由Dif依赖和Dif独立感知机制的相反力量控制的。我们认为，依赖于Dif但依赖于FRZ的PE感应导致了FrzCD甲基化和随后的适应的增加，而依赖于Dif的PE信号抑制或减少了FrzCD甲基化的增加，从而减慢或延迟了适应。我们认为，这些拮抗作用对于这种滑动细菌的有效趋化至关重要，以确保适应不会发生得太快，而不是像 一样以缓慢的速度移动。
Dif and Frz, twoMyxococcus xanthuschemosensory pathways, are required in phosphatidylethanolamine (PE) chemotaxis for excitation and adaptation respectively. DifA and FrzCD, the homologues of methyl‐accepting chemoreceptors in the two pathways, were examined for methylation in the context of chemotaxis and inter‐pathway interactions. Evidence indicates that DifA may not undergo methylation, but signals transmitting through DifA do modulate FrzCD methylation. Results also revealed thatM. xanthuspossesses Dif‐dependent and Dif‐independent PE‐sensing mechanisms. Previous studies showed that FrzCD methylation is decreased by negative chemostimuli but increased by attractants such as PE. Results here demonstrate that the Dif‐dependent sensory mechanism suppresses the increase in FrzCD methylation in attractant response and elevates FrzCD methylation upon negative stimulation. In other words, FrzCD methylation is governed by opposing forces from Dif‐dependent and Dif‐independent sensing mechanisms. We propose that the Dif‐independent but Frz‐dependent PE sensing leads to increases in FrzCD methylation and subsequent adaptation, while the Dif‐dependent PE signalling suppresses or diminishes the increase in FrzCD methylation to decelerate or delay adaptation. We contend that these antagonistic interactions are crucial for effective chemotaxis in this gliding bacterium to ensure that adaptation does not occur too quickly relative to the slow speed ofM. xanthusmovement.