Defining the function of OmpA in the Rcs stress response
- Universite catholique de Louvain, Belgium
- Université Grenoble Alpes, CNRS, CEA, France
- Université Paul Sabatier, France
- Université Grenoble Alpes, France
Abstract
OmpA, a protein commonly found in the outer membrane of Gram-negative bacteria, has served as a paradigm for the study of b-barrel proteins for several decades. In Escherichia coli, OmpA was previously reported to form complexes with RcsF, a surface-exposed lipoprotein that triggers the Rcs stress response when damage occurs in the outer membrane and the peptidoglycan. How OmpA interacts with RcsF and whether this interaction allows RcsF to reach the surface has remained unclear. Here, we integrated in vivo and in vitro approaches to establish that RcsF interacts with the C-terminal, periplasmic domain of OmpA, not with the N-terminal b-barrel, thus implying that RcsF does not reach the bacterial surface via OmpA. Our results suggest a novel function for OmpA in the cell envelope: OmpA competes with the inner membrane protein IgaA, the downstream Rcs component, for RcsF binding across the periplasm, thereby regulating the Rcs response.
Data availability
All data generated or analyzed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 3, 4A, 4B, 5B, 5D and 6 supplement 1.
Article and author information
Author details
Jean-Francois Collet
Funding
Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture
- Kilian Dekoninck
- Robin Bevernaegie
Fonds De La Recherche Scientifique - FNRS
- Kilian Dekoninck
- Juliette Létoquart
- Robin Bevernaegie
- Olivia Dehu
- Benjamin Elias
- Seung-Hyun Cho
FRFS-WELBIO
- Jean-Francois Collet
FRISBI (ANR-10-INBS-05-02)
- Cédric Laguri
- Jean-Pierre Simorre
GRAL
- Cédric Laguri
- Jean-Pierre Simorre
CBH-EUR-GS (ANR-17-EURE-0003)
- Cédric Laguri
- Jean-Pierre Simorre
Fédération Wallonie-Bruxelles (ARC 17/22-087)
- Jean-Francois Collet
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Dekoninck et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 3,052
- views
-
- 468
- downloads
-
- 29
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Defining the function of OmpA in the Rcs stress response
eLife 9:e60861.
https://doi.org/10.7554/eLife.60861
Further reading
-
- Microbiology and Infectious Disease
mRNA vaccines against SARS-CoV-2 were rapidly developed and were effective during the pandemic. However, some limitations remain to be resolved, such as the short-lived induced immune response and certain adverse effects. Therefore, there is an urgent need to develop new vaccines that address these issues. While live-attenuated vaccines are a highly effective modality, they pose a risk of adverse effects, including virulence reversion. In the current study, we constructed a live-attenuated vaccine candidate, BK2102, combining naturally occurring virulence-attenuating mutations in the NSP14, NSP1, spike, and ORF7-8 coding regions. Intranasal inoculation with BK2102 induced humoral and cellular immune responses in Syrian hamsters without apparent tissue damage in the lungs, leading to protection against a SARS-CoV-2 D614G and an Omicron BA.5 strains. The neutralizing antibodies induced by BK2102 persisted for up to 364 days, which indicated that they confer long-term protection against infection. Furthermore, we confirmed the safety of BK2102 using transgenic (Tg) mice expressing human ACE2 (hACE2) that are highly susceptible to SARS-CoV-2. BK2102 did not kill the Tg mice, even when virus was administered at a dose of 106 plaque-forming units (PFUs), while 102 PFU of the D614G strain or an attenuated strain lacking the furin cleavage site of the spike was sufficient to kill mice. These results suggest that BK2102 is a promising live-vaccine candidate strain that confers long-term protection without significant virulence.
-
- Microbiology and Infectious Disease
The drivers of tissue necrosis in Mycobacterium ulcerans infection (Buruli ulcer disease) have historically been ascribed solely to the directly cytotoxic action of the diffusible exotoxin, mycolactone. However, its role in the clinically evident vascular component of disease aetiology remains poorly explained. We have now dissected mycolactone’s effects on human primary vascular endothelial cells in vitro. We show that mycolactone-induced changes in endothelial morphology, adhesion, migration, and permeability are dependent on its action at the Sec61 translocon. Unbiased quantitative proteomics identified a profound effect on proteoglycans, driven by rapid loss of type II transmembrane proteins of the Golgi, including enzymes required for glycosaminoglycan (GAG) synthesis, combined with a reduction in the core proteins themselves. Loss of the glycocalyx is likely to be of particular mechanistic importance, since knockdown of galactosyltransferase II (beta-1,3-galactotransferase 6; B3GALT6), the GAG linker-building enzyme, phenocopied the permeability and phenotypic changes induced by mycolactone. Additionally, mycolactone depleted many secreted basement membrane components and microvascular basement membranes were disrupted in vivo during M. ulcerans infection in the mouse model. Remarkably, exogenous addition of laminin-511 reduced endothelial cell rounding, restored cell attachment and reversed the defective migration caused by mycolactone. Hence supplementing mycolactone-depleted extracellular matrix may be a future therapeutic avenue, to improve wound healing rates.
