Systems Biology Approach to Study the Escherichia coli Two-Component Signal Transduction Interactome

所有生物都在不断地调整以适应环境的变化。单细胞微生物使用一种被称为双组分调节剂的蛋白质家族来感知环境的变化，并产生适应性变化。每个双组分系统由一个暴露在细胞外部以检测环境参数的传感器蛋白和一个与传感器通信并在基因表达中做出适当改变的调节蛋白组成。微生物可能拥有数十或数百个双组分系统，每个系统对不同的环境线索作出反应。最近的研究表明，一些双组分系统是通过称为连接器的信号蛋白连接起来的。连接器由一个双组件系统打开，并影响另一个双组件系统的信令活动。这些连接允许形成一个细胞调节网络，通过整合多个双组分系统的活动来实现对给定信号的最佳适应。在这个提议中，我假设在30个具有良好特征的模式生物大肠杆菌的双组分系统之间存在着额外的、未被发现的联系。我们将首先通过比较单个双组分通路打开时获得的基因表达谱来识别连接的双组分系统。一旦我们确定了双组分系统之间的联系，我们将使用基因筛选来确定负责建立这种联系的“连接器”。最后，我们将了解这些连接器是如何工作的。先前确定的连接器通过与受影响的双组分系统的传感器或调节器相互作用来改变其活动。我们将设置实验来评估双组分系统的哪个成员受到连接器的影响，以及如何影响。由于双组分调节因子在控制涉及疾病病因和代谢的细菌活动中发挥重要作用，这项工作有可能揭示如何治疗微生物感染以及如何利用细菌生产有用化合物的新思路。

All organisms make continual adjustments to account for changes in their environments. Single celled microbes use a family of proteins called two-component regulators to sense alterations in their environments and institute adaptive changes. Each two-component system consists of a sensor protein that is exposed to the outside of the cell to detect environmental parameters and a regulator protein that communicates with the sensor and makes appropriate changes in gene expression. A microbe may possess tens or hundreds of two-component systems, each one responsive to a different environmental cue. Recent studies indicate that some two-component systems are connected by means of signaling proteins called connectors. Connectors are turned on by one two-component system and influence the signaling activities of another two-component system. These connections allow for the formation of a cellular regulatory network that results in optimal adaptation to a given signal by integrating the activities of multiple two-component systems. In this proposal, I hypothesize that additional, undiscovered connections exist between the 30 two-component systems of the well-characterized model organism Escherichia coli. We will first identify connected two-component systems by comparing gene expression profiles obtained when individual two-component pathways are turned on. Once we have identified connections between two-component systems, we will use genetic screens to identify the "connectors" that are responsible for making the connections. Finally, we will figure out how these connectors work. Previously identified connectors work by interacting with the sensor or the regulator of the affected two-component system to alter its activity. We will set up experiments to evaluate which member of the two-component system is affected by the connector, and how. Since two-component regulators play important roles in controlling bacterial activities involved in disease causation and metabolism, this work has the potential to uncover new ideas about how to treat microbial infections and how to harness bacteria for the production of useful compounds.