Two-component signal transduction systems enable bacteria to sense, respond, and adapt to a wide range of environments, stressors, and growth conditions. In the prototypical two-component system, a sensor histidine kinase catalyzes its autophosphorylation and then subsequently transfers the phosphoryl group to a response regulator, which can then effect changes in cellular physiology, often by regulating gene expression. The utility of these signaling systems is underscored by their prevalence throughout the bacterial kingdom and by the fact that many bacteria contain dozens, or sometimes hundreds, of these signaling proteins. The presence of so many highly related signaling proteins in individual cells creates both an opportunity and a challenge. Do cells take advantage of the similarity between signaling proteins to integrate signals or diversify responses, and thereby enhance their ability to process information? Conversely, how do cells prevent unwanted cross-talk and maintain the insulation of distinct pathways? Here we address both questions by reviewing the cellular and molecular mechanisms that dictate the specificity of two-component signaling pathways.

中文翻译：

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两组分信号转导途径的特异性。

两成分信号转导系统使细菌能够感应，响应并适应各种环境，应激源和生长条件。在典型的两组分系统中，传感器组氨酸激酶催化其自身磷酸化，然后将磷酰基转移至响应调节剂，然后通常可以通过调节基因表达来影响细胞生理学变化。这些信号传导系统的实用性因其在整个细菌界的普遍性以及许多细菌包含数十种或有时数百种这些信号传导蛋白的事实而得到强调。单个细胞中如此众多高度相关的信号蛋白的存在既带来了机遇，也带来了挑战。细胞是否利用信号蛋白之间的相似性来整合信号或使反应多样化，从而增强其处理信息的能力？相反，细胞如何防止不必要的串扰并保持不同途径的绝缘？在这里，我们通过审查指示两组分信号传导途径特异性的细胞和分子机制来解决这两个问题。