Fundamental Constraints on the Abundances of Chemotaxis Proteins
Fundamental Constraints on the Abundances of Chemotaxis Proteins
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DOI：
10.1016/j.bpj.2015.01.024
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发表时间：
2015-03-10
影响因子：
3.4
通讯作者：
Wingreen, Ned S.
中科院分区：
文献类型：
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作者：
Bitbol, Anne-Florence;Wingreen, Ned S.
有鞭毛的细菌，如大肠杆菌，在一个称为趋化性的过程中，在引诱剂和排斥剂的浓度梯度中进行定向运动。急诊大肠杆菌趋化性信号通路是一种信号转导的模型，但它有其独特之处。我们证明，需要快速的信号需要高丰度的蛋白质参与这一途径。我们表明，进一步限制趋化性蛋白的丰度产生的鞭毛电机和化学感受器阵列的自组装的要求。所有这些限制都是特定于趋化性的，已发表的数据证实趋化性蛋白往往比其他途径中的同源物表达更高。采用一个趋化途径模型，我们表明，在响应调节剂CheY的水平上的途径的增益增加与整体趋化蛋白丰度。这可以解释为什么，至少在一个E。大肠杆菌菌株中，所有趋化蛋白的丰度在营养含量较低的培养基中较高。我们还证明了E.大肠杆菌趋化途径对马达蛋白FliM的丰度变化特别稳健。
Flagellated bacteria, such as Escherichia coli, perform directed motion in gradients of concentration of attractants and repellents in a process called chemotaxis. The E. coli chemotaxis signaling pathway is a model for signal transduction, but it has unique features. We demonstrate that the need for fast signaling necessitates high abundances of the proteins involved in this pathway. We show that further constraints on the abundances of chemotaxis proteins arise from the requirements of self-assembly both of flagellar motors and of chemoreceptor arrays. All these constraints are specific to chemotaxis, and published data confirm that chemotaxis proteins tend to be more highly expressed than their homologs in other pathways. Employing a chemotaxis pathway model, we show that the gain of the pathway at the level of the response regulator CheY increases with overall chemotaxis protein abundances. This may explain why, at least in one E. coli strain, the abundance of all chemotaxis proteins is higher in media with lower nutrient content. We also demonstrate that the E. coli chemotaxis pathway is particularly robust to abundance variations of the motor protein FliM.