Conformational rearrangements in the sensory RcsF/OMP complex mediate signal transduction across the bacterial cell envelope.
Conformational rearrangements in the sensory RcsF/OMP complex mediate signal transduction across the bacterial cell envelope.
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DOI：
10.1371/journal.pgen.1010601
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发表时间：
2023-01
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影响因子：
4.5
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中科院分区：
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及时检测和修复包膜损伤对于细菌的生存至关重要。被膜合成调节因子（Regulator of Capsule Synthesis，Rcs）应激反应可以将应激信号传递到革兰氏阴性细胞的膜上，从而调节细胞质中的基因表达。以前的研究定义了整个途径，该途径始于感觉脂蛋白RcsF与几种外膜蛋白（OMP）的相互作用。RcsF还可以与负调节因子IgaA的周质结构域相互作用，从而解抑制下游RcsCDB磷酸化中继。然而，RcsF/IgaA相互作用如何在分子水平上调节以激活响应于应激的信号传导仍然知之甚少。在这项研究中，我们使用了一个网站饱和的突变库的rcsF进行了几个独立的遗传筛选，询问从RcsF的信号转导IgaA的机制。我们分析了几种不同类型的rcsF信号转导突变体，并确定了区域的RcsF是至关重要的信号转导。该区域是双功能的，因为它对于RcsF与IgaA和OMP的相互作用是重要的。突变体分析提供了强有力的证据，RcsF/OMP复合物介导的信号转导IgaA的构象变化，和第一个直接的证据，OMP发挥重要的调节作用，Rcs信号。荚膜合成调节因子（Regulator of Capsule Synthesis，Rcs）是一种信号通路，可以检测细菌细胞最外层的损伤，并将信息传递到细胞内以诱导保护性反应。Rcs信号传导机制知之甚少，特别是调节下游磷酸化中继活性的信号转导的早期步骤。在这项研究中，我们展示了Rcs系统如何依赖于蛋白质组分相互作用的变化，类似于多米诺骨牌效应。在应对压力时，传感器蛋白RcsF与外膜蛋白合作，经历构象变化，促进其接近信号传导抑制剂IgaA，释放制动器并允许信号传导在细胞内进行。
Timely detection and repair of envelope damage are paramount for bacterial survival. The Regulator of Capsule Synthesis (Rcs) stress response can transduce the stress signals across the multilayered gram-negative cell envelope to regulate gene expression in the cytoplasm. Previous studies defined the overall pathway, which begins with the sensory lipoprotein RcsF interacting with several outer membrane proteins (OMPs). RcsF can also interact with the periplasmic domain of the negative regulator IgaA, derepressing the downstream RcsCDB phosphorelay. However, how the RcsF/IgaA interaction is regulated at the molecular level to activate the signaling in response to stress remains poorly understood. In this study, we used a site-saturated mutant library of rcsF to carry out several independent genetic screens to interrogate the mechanism of signal transduction from RcsF to IgaA. We analyzed several distinct classes of rcsF signaling mutants, and determined the region of RcsF that is critically important for signal transduction. This region is bifunctional as it is important for RcsF interaction with both IgaA and OMPs. The mutant analysis provides strong evidence for conformational changes in the RcsF/OMP complex mediating signal transduction to IgaA, and the first direct evidence that OMPs play an important regulatory role in Rcs signaling. Regulator of Capsule Synthesis (Rcs) is a signaling pathway that can detect damage in the most outer layers of the bacterial cell, and transmits the information inside the cell to induce a protective response. The Rcs signaling mechanism is poorly understood, especially the early steps of signal transduction that regulate activity of downstream phosphorelay. In this study, we show how the Rcs system relies on changes in how protein components interact, similar to a domino effect. In response to stress, the sensor protein RcsF, partnered with outer membrane proteins, undergoes conformational changes that facilitate its access to the signaling inhibitor IgaA, releasing the brakes and allowing signaling to proceed inside the cell.