RcsF-independent mechanisms of signaling within the Rcs phosphorelay.

IF 4 2区 生物学 Q1 GENETICS & HEREDITY
PLoS Genetics Pub Date : 2024-12-26 eCollection Date: 2024-12-01 DOI:10.1371/journal.pgen.1011408
Anushya Petchiappan, Nadim Majdalani, Erin Wall, Susan Gottesman
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引用次数: 0

Abstract

The Rcs (regulator of capsule synthesis) phosphorelay is a conserved cell envelope stress response mechanism in enterobacteria. It responds to perturbations at the cell surface and the peptidoglycan layer from a variety of sources, including antimicrobial peptides, beta-lactams, and changes in osmolarity. RcsF, an outer membrane lipoprotein, is the sensor for this pathway and activates the phosphorelay by interacting with an inner membrane protein IgaA. IgaA is essential; it negatively regulates the signaling by interacting with the phosphotransferase RcsD. We previously showed that RcsF-dependent signaling does not require the periplasmic domain of the histidine kinase RcsC and identified a dominant negative mutant of RcsD that can block signaling via increased interactions with IgaA. However, how the inducing signals are sensed and how signal is transduced to activate the transcription of the Rcs regulon remains unclear. In this study, we investigated how the Rcs cascade functions without its only known sensor, RcsF, and characterized the underlying mechanisms for three distinct RcsF-independent inducers. Previous reports showed that Rcs activity can be induced in the absence of RcsF by a loss of function mutation in the periplasmic oxidoreductase DsbA or by overexpression of the DnaK cochaperone DjlA. We identified an inner membrane protein, DrpB, as a multicopy RcsF-independent Rcs activator in E. coli. The loss of the periplasmic oxidoreductase DsbA and the overexpression of the DnaK cochaperone DjlA each trigger the Rcs cascade in the absence of RcsF by weakening IgaA-RcsD interactions in different ways. In contrast, the cell-division associated protein DrpB uniquely requires the RcsC periplasmic domain for activation; this domain is not needed for RcsF-dependent signaling. This suggests the possibility that the RcsC periplasmic domain acts as a sensor for some Rcs signals. Overall, the results add new understanding to how this complex phosphorelay can be activated by diverse mechanisms.

Rcs磷接力中与Rcs无关的信号传导机制。
在肠杆菌中,Rcs (capsule synthesis regulator of phosphorelay)是一种保守的细胞包膜应激反应机制。它对来自各种来源的细胞表面和肽聚糖层的扰动作出反应,包括抗菌肽、β -内酰胺和渗透压的变化。RcsF,一种外膜脂蛋白,是该途径的传感器,并通过与内膜蛋白IgaA相互作用激活磷接力。IgaA是必不可少的;它通过与磷酸转移酶RcsD相互作用负向调节信号传导。我们之前的研究表明,rcsf依赖的信号不需要组氨酸激酶RcsC的周质结构域,并发现了RcsD的显性负突变体,该突变体可以通过增加与IgaA的相互作用来阻断信号传导。然而,诱导信号如何被感知以及信号如何被转导以激活Rcs调控子的转录仍不清楚。在这项研究中,我们研究了Rcs级联如何在没有其唯一已知传感器RcsF的情况下发挥作用,并表征了三种不同的RcsF独立诱导剂的潜在机制。先前的报道表明,在RcsF缺失的情况下,Rcs的活性可以通过质周氧化还原酶DsbA的功能突变丧失或DnaK伴侣蛋白DjlA的过表达来诱导。我们在大肠杆菌中发现了一种内膜蛋白DrpB,它是一种多拷贝rcsf独立的Rcs激活剂。质周氧化还原酶DsbA的缺失和DnaK合作伙伴DjlA的过表达都通过以不同方式削弱IgaA-RcsD相互作用,在RcsF缺失的情况下触发Rcs级联反应。相反,细胞分裂相关蛋白DrpB需要RcsC周围质域才能激活;依赖于rcsf的信令不需要这个域。这表明RcsC周围质域可能作为一些Rcs信号的传感器。总的来说,这些结果为这种复杂的磷接力如何通过不同的机制被激活提供了新的认识。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
PLoS Genetics
PLoS Genetics GENETICS & HEREDITY-
自引率
2.20%
发文量
438
期刊介绍: PLOS Genetics is run by an international Editorial Board, headed by the Editors-in-Chief, Greg Barsh (HudsonAlpha Institute of Biotechnology, and Stanford University School of Medicine) and Greg Copenhaver (The University of North Carolina at Chapel Hill). Articles published in PLOS Genetics are archived in PubMed Central and cited in PubMed.
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