Bacterial two-component systems (TCS) are versatile signaling mechanisms that govern cellular responses to diverse environmental cues. These systems rely on phosphoryl-group transfers between histidine- and aspartate-containing modules of sensor histidine kinase and response regulator proteins. TCS diversity is shaped by the ecological niche of the bacterium, resulting in significant population-level variations. Consequently, orthologous TCSs can display considerable divergence throughout the signaling process. Here, we venture into the mechanisms governing the emergence of TCS variation, and explore the adaptation of orthologous TCS in bacteria with dissimilar lifestyles. The peculiar features of the bacterial adaptive response A/ultraviolet light repair Y (BarA/UvrY) and anoxic redox control B/anoxic redox control A (ArcB/ArcA) and their ortholog TCSs illustrate the remarkable capacity of TCSs to evolve and finely tune their signaling mechanisms, effectively addressing specific environmental challenges.

细菌双组分系统 (TCS) 是一种多功能信号机制，可控制细胞对不同环境信号的反应。这些系统依赖于传感器组氨酸激酶和反应调节蛋白的含组氨酸和天冬氨酸模块之间的磷酰基转移。TCS 多样性是由细菌的生态位决定的，从而导致显着的种群水平差异。因此，直系同源 TCS 在整个信令过程中可能表现出相当大的分歧。在这里，我们深入研究 TCS 变异出现的机制，并探索直系同源 TCS 在具有不同生活方式的细菌中的适应。细菌适应性反应 A/紫外线修复 Y (BarA/UvrY) 和缺氧氧化还原控制 B/缺氧氧化还原控制 A (ArcB/ArcA) 及其直系同源 TCS 的独特特征说明了 TCS 进化和微调其自身特性的卓越能力。信号机制，有效应对特定的环境挑战。