1
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Sagoo J, Abedrabbo S, Liu X, Ottemann KM. Helicobacter pylori cheV1 mutants recover semisolid agar migration due to loss of a previously uncharacterized Type IV filament membrane alignment complex homolog. J Bacteriol 2024; 206:e0040623. [PMID: 38446058 PMCID: PMC11025336 DOI: 10.1128/jb.00406-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/21/2024] [Indexed: 03/07/2024] Open
Abstract
The bacterial chemotaxis system is a well-understood signaling pathway that promotes bacterial success. Chemotaxis systems comprise chemoreceptors and the CheA kinase, linked by CheW or CheV scaffold proteins. Scaffold proteins provide connections between chemoreceptors and CheA and also between chemoreceptors to create macromolecular arrays. Chemotaxis is required for host colonization by many microbes, including the stomach pathogen Helicobacter pylori. This bacterium builds chemoreceptor-CheA contacts with two distinct scaffold proteins, CheW and CheV1. H. pylori cheW or cheV1 deletion mutants both lose chemoreceptor array formation, but show differing semisolid agar chemotaxis assay behaviors: ∆cheW mutants exhibit total migration failure, whereas ∆cheV1::cat mutants display a 50% reduction. On investigating these varied responses, we found that both mutants initially struggle with migration. However, over time, ∆cheV1::cat mutants develop a stable, enhanced migration capability, termed "migration-able" (Mig+). Whole-genome sequencing analysis of four distinct ∆cheV1::cat Mig+ strains identified single-nucleotide polymorphisms (SNPs) in hpg27_252 (hp0273) that were predicted to truncate the encoded protein. Computational analysis of the hpg27_252-encoded protein revealed it encoded a hypothetical protein that was a remote homolog of the PilO Type IV filament membrane alignment complex protein. Although H. pylori lacks Type IV filaments, our analysis showed it retains an operon of genes for homologs of PilO, PilN, and PilM. Deleting hpg27_252 in the ∆cheV1::cat or wild type strain resulted in enhanced migration in semisolid agar. Our study thus reveals that while cheV1 mutants initially have significant migration defects, they can recover the migration ability through genetic suppressors, highlighting a complex regulatory mechanism in bacterial migration. IMPORTANCE Chemotactic motility, present in over half of bacteria, depends on chemotaxis signaling systems comprising receptors, kinases, and scaffold proteins. In Helicobacter pylori, a stomach pathogen, chemotaxis is crucial for colonization, with CheV1 and CheW as key scaffold proteins. While both scaffolds are essential for building chemoreceptor complexes, their roles vary in other assays. Our research reexamines cheV1 mutants' behavior in semisolid agar, a standard chemotaxis test. Initially, cheV1 mutants exhibited defects similar to those of cheW mutants, but they evolved genetic suppressors that enhanced migration. These suppressors involve mutations in a previously uncharacterized gene, unknown in motility behavior. Our findings highlight the significant chemotaxis defects in cheV1 mutants and identify new elements influencing bacterial motility.
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Affiliation(s)
- Jashwin Sagoo
- Department of Microbiology and Environmental Toxicology, UC Santa Cruz, Santa Cruz, California, USA
| | - Samar Abedrabbo
- Department of Microbiology and Environmental Toxicology, UC Santa Cruz, Santa Cruz, California, USA
| | - Xiaolin Liu
- Department of Microbiology and Environmental Toxicology, UC Santa Cruz, Santa Cruz, California, USA
| | - Karen M. Ottemann
- Department of Microbiology and Environmental Toxicology, UC Santa Cruz, Santa Cruz, California, USA
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2
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Liu X, Tachiyama S, Zhou X, Mathias RA, Bonny SQ, Khan MF, Xin Y, Roujeinikova A, Liu J, Ottemann KM. Bacterial flagella hijack type IV pili proteins to control motility. Proc Natl Acad Sci U S A 2024; 121:e2317452121. [PMID: 38236729 PMCID: PMC10823254 DOI: 10.1073/pnas.2317452121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 11/27/2023] [Indexed: 01/23/2024] Open
Abstract
Bacterial flagella and type IV pili (TFP) are surface appendages that enable motility and mechanosensing through distinct mechanisms. These structures were previously thought to have no components in common. Here, we report that TFP and some flagella share proteins PilO, PilN, and PilM, which we identified as part of the Helicobacter pylori flagellar motor. H. pylori mutants lacking PilO or PilN migrated better than wild type in semisolid agar because they continued swimming rather than aggregated into microcolonies, mimicking the TFP-regulated surface response. Like their TFP homologs, flagellar PilO/PilN heterodimers formed a peripheral cage that encircled the flagellar motor. These results indicate that PilO and PilN act similarly in flagella and TFP by differentially regulating motility and microcolony formation when bacteria encounter surfaces.
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Affiliation(s)
- Xiaolin Liu
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA95064
| | - Shoichi Tachiyama
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT06536
- Microbial Sciences Institute, Yale University, West Haven, CT06516
| | - Xiaotian Zhou
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC3800, Australia
| | - Rommel A. Mathias
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC3800, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC3800, Australia
| | - Sharmin Q. Bonny
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC3800, Australia
| | - Mohammad F. Khan
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC3800, Australia
| | - Yue Xin
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC3800, Australia
| | - Anna Roujeinikova
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC3800, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC3800, Australia
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT06536
- Microbial Sciences Institute, Yale University, West Haven, CT06516
| | - Karen M. Ottemann
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA95064
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3
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Li Y, Santos-Moreno J, Francetic O. The periplasmic coiled coil formed by the assembly platform proteins PulL and PulM is critical for function of the Klebsiella type II secretion system. Res Microbiol 2023; 174:104075. [PMID: 37141929 DOI: 10.1016/j.resmic.2023.104075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/06/2023]
Abstract
Bacteria use type II secretion systems (T2SS) to secrete to their surface folded proteins that confer diverse functions, from nutrient acquisition to virulence. In the Klebsiella species, T2SS-mediated secretion of pullulanase (PulA) requires assembly of a dynamic filament called the endopilus. The inner membrane assembly platform (AP) subcomplex is essential for endopilus assembly and PulA secretion. AP components PulL and PulM interact with each other through their C-terminal globular domains and transmembrane segments. Here, we investigated the roles of their periplasmic helices, predicted to form a coiled coil, in assembly and function of the PulL-PulM complex. PulL and PulM variants lacking these periplasmic helices were defective for interaction in the bacterial two-hybrid (BACTH) assay. Their functions in PulA secretion and assembly of PulG subunits into endopilus filaments were strongly reduced. Interestingly, deleting the cytoplasmic peptide of PulM nearly abolished the function of variant PulMΔN and its interaction with PulG, but not with PulL, in the BACTH assay. Nevertheless, PulL was specifically proteolyzed in the presence of the PulMΔN variant, suggesting that PulM N-terminal peptide stabilizes PulL in the cytoplasm. We discuss the implications of these results for the T2S endopilus and type IV pilus assembly mechanisms.
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Affiliation(s)
- Yuanyuan Li
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Biochemistry of Macromolecular Interactions Unit, F-75015 Paris, France.
| | - Javier Santos-Moreno
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Biochemistry of Macromolecular Interactions Unit, F-75015 Paris, France.
| | - Olivera Francetic
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Biochemistry of Macromolecular Interactions Unit, F-75015 Paris, France.
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4
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Sagoo J, Abedrabbo S, Liu X, Ottemann KM. Discovery of Type IV filament membrane alignment complex homologs in H. pylori that promote soft-agar migration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.27.537399. [PMID: 37163056 PMCID: PMC10168365 DOI: 10.1101/2023.04.27.537399] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The stomach pathogen Helicobacter pylori utilizes two scaffold proteins, CheW and CheV1, to build critical chemotaxis arrays. Chemotaxis helps bacteria establish and maintain infection. Mutants lacking either of these chemotaxis proteins have different soft agar phenotypes: deletion of cheW creates non-chemotactic strains, while deletion of cheV1 results in 50% loss of chemotaxis. In this work, we characterized the cheV1 deletion mutant phenotype in detail. cheV1 deletion mutants had poor soft-agar migration initially, but regained migration ability over time. This improved bacterial migration was stable, suggesting a genetic suppressor phenotype, termed Che+. Whole-genome sequencing analysis of four distinct cheV1 Che+ strains revealed single nucleotide polymorphisms (SNPs) in a common gene, HPG27_252 (HP0273). These SNPs were predicted to truncate the encoded protein. To confirm the role of HPG27_252 in the cheV1 phenotype, we created a targeted deletion of HPG27_252 and found that loss of HPG27_252 enhanced soft-agar migration. HPG27_252 and CheV1 appear to interact directly, based on bacterial two-hybrid analysis. HPG27_252 is predicted to encode a 179 amino acid, 21 kDa protein annotated as a hypothetical protein. Computational analysis revealed this protein to be a remote homolog of the PilO Type IV filament membrane alignment complex protein. Although H. pylori is not known to possess Type IV filaments, our analysis showed it retains an operon of genes for homologs of PilO, PilN, and PilM, but does not possess other Type IV pili genes. Our data suggest the PilO homolog plays a role in regulating H. pylori chemotaxis and motility, suggesting new ideas about evolutionary steps for controlling migration through semi-solid media.
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5
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Mou L, Peng X, Chen Y, Xiao Q, Liao H, Liu M, Guo L, Liu Y, Zhang X, Deng D. Crystal structure of monomeric Amuc_1100 from Akkermansia muciniphila. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2020; 76:168-174. [PMID: 32254050 DOI: 10.1107/s2053230x20004124] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/24/2020] [Indexed: 01/10/2023]
Abstract
Many human diseases, such as obesity and diabetes, show annual increases in prevalence and often involve intestinal microbes. One such probiotic bacterium, Akkermansia muciniphila, which was discovered a decade ago, has been reported to influence glucose homeostasis and to contribute to gut health. Amuc_1100, a functionally uncharacterized protein of A. muciniphila, was found to be a key active component in reducing the body weight of mice. Here, the crystal structure of Amuc_1100 (residues 31-317), referred to as Amuc_1100*, is reported at 2.1 Å resolution. Amuc_1100* has a similar fold to three proteins related to pilus formation, PilO, PilN and EpsL, indicating a similar function. Biochemical investigations further confirmed a monomeric state for the soluble region of Amuc_1100, which differs from the dimeric states of PilO, PilN and EpsL. This study provides a structural basis for the elucidation of the molecular mechanism of Amuc_1100.
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Affiliation(s)
- Luqiu Mou
- Division of Obstetrics, Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Xi Peng
- Division of Obstetrics, Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Yan Chen
- Sichuan University-The Chinese University of Hong Kong Joint Laboratory for Reproductive Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Qingjie Xiao
- Division of Obstetrics, Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Huijuan Liao
- Sichuan University-The Chinese University of Hong Kong Joint Laboratory for Reproductive Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Mingfeng Liu
- Sichuan University-The Chinese University of Hong Kong Joint Laboratory for Reproductive Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Li Guo
- Division of Obstetrics, Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Yang Liu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Xiaohu Zhang
- Sichuan University-The Chinese University of Hong Kong Joint Laboratory for Reproductive Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Dong Deng
- Division of Obstetrics, Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
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6
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Ghosal D, Kim KW, Zheng H, Kaplan M, Truchan HK, Lopez AE, McIntire IE, Vogel JP, Cianciotto NP, Jensen GJ. In vivo structure of the Legionella type II secretion system by electron cryotomography. Nat Microbiol 2019; 4:2101-2108. [PMID: 31754273 PMCID: PMC6879910 DOI: 10.1038/s41564-019-0603-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022]
Abstract
The type II secretion system (T2SS) is a multiprotein envelope-spanning assembly that translocates a wide range of virulence factors, enzymes and effectors through the outer membrane of many Gram-negative bacteria1-3. Here, using electron cryotomography and subtomogram averaging methods, we reveal the in vivo structure of an intact T2SS imaged within the human pathogen Legionella pneumophila. Although the T2SS has only limited sequence and component homology with the evolutionarily related type IV pilus (T4P) system4,5, we show that their overall architectures are remarkably similar. Despite similarities, there are also differences, including, for example, that the T2SS-ATPase complex is usually present but disengaged from the inner membrane, the T2SS has a much longer periplasmic vestibule and it has a short-lived flexible pseudopilus. Placing atomic models of the components into our electron cryotomography map produced a complete architectural model of the intact T2SS that provides insights into the structure and function of its components, its position within the cell envelope and the interactions between its different subcomplexes.
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Affiliation(s)
- Debnath Ghosal
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Ki Woo Kim
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- School of Ecology and Environmental System, Kyungpook National University, Sangju, Korea
| | - Huaixin Zheng
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Department of Immunology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou City, Henan Province, China
| | - Mohammed Kaplan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Hilary K Truchan
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Alberto E Lopez
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Ian E McIntire
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Joseph P Vogel
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, USA
| | - Nicholas P Cianciotto
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
- Howard Hughes Medical Institute, Pasadena, CA, USA.
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7
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Abstract
Type IV pilus (T4P)-like systems have been identified in almost every major phylum of prokaryotic life. They include the type IVa pilus (T4aP), type II secretion system (T2SS), type IVb pilus (T4bP), Tad/Flp pilus, Com pilus, and archaeal flagellum (archaellum). These systems are used for adhesion, natural competence, phage adsorption, folded-protein secretion, surface sensing, swimming motility, and twitching motility. The T4aP allows for all of these functions except swimming and is therefore a good model system for understanding T4P-like systems. Recent structural analyses have revolutionized our understanding of how the T4aP machinery assembles and functions. Here we review the structure and function of the T4aP.
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8
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Persyn E, Sassi M, Aubry M, Broly M, Delanou S, Asehnoune K, Caroff N, Crémet L. Rapid genetic and phenotypic changes in Pseudomonas aeruginosa clinical strains during ventilator-associated pneumonia. Sci Rep 2019; 9:4720. [PMID: 30886315 PMCID: PMC6423012 DOI: 10.1038/s41598-019-41201-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 02/27/2019] [Indexed: 11/24/2022] Open
Abstract
Treatment with antibiotics leads to the selection of isolates with increased resistance. We investigated if evolution towards resistance was associated with virulence changes, in the context of P. aeruginosa ventilator-associated pneumonia (VAP). Four patients were selected because they had multiple VAP episodes during short periods (12 days to 5 weeks), with emergence of resistance. We performed whole-genome sequencing of 12 P. aeruginosa from bronchoalveolar lavages or blood culture (3 isolates per patient). Production of quorum sensing-dependent virulence factors, serum resistance, cytotoxicity against A549 cells, biofilm production, and twitching motility were studied. Each patient was infected with a unique strain. For all patients, resistance development was explained by genetic events in ampD, mexR or oprD. Additional variations were detected in virulence- and/or fitness-associated genes (algB, gacA, groEL, lasR, mpl, pilE, pilM, rhlR) depending on the strain. We noticed a convergence towards quorum sensing deficiency, correlated with a decrease of pyocyanin and protease production, survival in serum, twitching motility and cytotoxicity. In one patient, changes in pilM and pilE were related to enhanced twitching. We show that the emergence of resistance in P. aeruginosa is associated with virulence modification, even in acute infections. The consequences of this short-term pathoadaptation need to be explored.
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Affiliation(s)
- Elise Persyn
- EA3826 Université de Nantes, IRS2 Nantes Biotech, Nantes Cedex 1, F-44100, France.
- CHU Nantes, 9 quai Moncousu, Nantes Cedex 1, F-44093, France.
| | - Mohamed Sassi
- Inserm U835, Université de Rennes, Rennes, F-35000, France
| | - Marc Aubry
- Université de Rennes, CNRS, IGDR [(Institut de génétique et développement de Rennes)] - UMR 6290, F-35000, Rennes, France
- Université de Rennes, Plateforme GEH, CNRS, Inserm, BIOSIT - UMS 3480, US_S 018, F-35000, Rennes, France
| | - Martin Broly
- CHU Nantes, 9 quai Moncousu, Nantes Cedex 1, F-44093, France
| | - Sandie Delanou
- EA3826 Université de Nantes, IRS2 Nantes Biotech, Nantes Cedex 1, F-44100, France
| | - Karim Asehnoune
- EA3826 Université de Nantes, IRS2 Nantes Biotech, Nantes Cedex 1, F-44100, France
- CHU Nantes, 9 quai Moncousu, Nantes Cedex 1, F-44093, France
| | - Nathalie Caroff
- EA3826 Université de Nantes, IRS2 Nantes Biotech, Nantes Cedex 1, F-44100, France
| | - Lise Crémet
- EA3826 Université de Nantes, IRS2 Nantes Biotech, Nantes Cedex 1, F-44100, France
- CHU Nantes, 9 quai Moncousu, Nantes Cedex 1, F-44093, France
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9
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Kruse K, Salzer R, Averhoff B. The traffic ATPase PilF interacts with the inner membrane platform of the DNA translocator and type IV pili from Thermus thermophilus. FEBS Open Bio 2018; 9:4-17. [PMID: 30652069 PMCID: PMC6325625 DOI: 10.1002/2211-5463.12548] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/10/2018] [Accepted: 10/25/2018] [Indexed: 12/20/2022] Open
Abstract
A major driving force for the adaptation of bacteria to changing environments is the uptake of naked DNA from the environment by natural transformation, which allows the acquisition of new capabilities. Uptake of the high molecular weight DNA is mediated by a complex transport machinery that spans the entire cell periphery. This DNA translocator catalyzes the binding and splitting of double‐stranded DNA and translocation of single‐stranded DNA into the cytoplasm, where it is recombined with the chromosome. The thermophilic bacterium Thermus thermophilus exhibits the highest transformation frequencies reported and is a model system to analyze the structure and function of this macromolecular transport machinery. Transport activity is powered by the traffic ATPase PilF, a soluble protein that forms hexameric complexes. Here, we demonstrate that PilF physically binds to an inner membrane assembly platform of the DNA translocator, comprising PilMNO, via the ATP‐binding protein PilM. Binding to PilMNO or PilMN stimulates the ATPase activity of PilF ~ 2‐fold, whereas there is no stimulation when binding to PilM or PilN alone. A PilMK26A variant defective in ATP binding still binds PilF and, together with PilN, stimulates PilF‐mediated ATPase activity. PilF is unique in having three conserved GSPII (general secretory pathway II) domains (A–C) at its N terminus. Deletion analyses revealed that none of the GSPII domains is essential for binding PilMN, but GSPIIC is essential for PilMN‐mediated stimulation of ATP hydrolysis by PilF. Our data suggest that PilM is a coupling protein that physically and functionally connects the soluble motor ATPase PilF to the DNA translocator via the PilMNO assembly platform.
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Affiliation(s)
- Kerstin Kruse
- Molecular Microbiology & Bioenergetics Institute of Molecular Biosciences Goethe University Frankfurt Germany
| | - Ralf Salzer
- Molecular Microbiology & Bioenergetics Institute of Molecular Biosciences Goethe University Frankfurt Germany.,Present address: Structural Studies Division Medical Research Council - Laboratory of Molecular Biology Cambridge Biomedical Campus, Francis Crick Ave Cambridge CB2 OQH UK
| | - Beate Averhoff
- Molecular Microbiology & Bioenergetics Institute of Molecular Biosciences Goethe University Frankfurt Germany
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10
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Fulara A, Vandenberghe I, Read RJ, Devreese B, Savvides SN. Structure and oligomerization of the periplasmic domain of GspL from the type II secretion system of Pseudomonas aeruginosa. Sci Rep 2018; 8:16760. [PMID: 30425318 PMCID: PMC6233222 DOI: 10.1038/s41598-018-34956-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/27/2018] [Indexed: 01/12/2023] Open
Abstract
The ability of bacteria to infect a host relies in part on the secretion of molecular virulence factors across the cell envelope. Pseudomonas aeruginosa, a ubiquitous environmental bacterium causing opportunistic infections in humans, employs the type II secretion system (T2SS) to transport effector proteins across its cellular envelope as part of a diverse array of virulence strategies. General secretory pathway protein L (GspL) is an essential inner-membrane component of the T2SS apparatus, and is thought to facilitate transduction of the energy from ATP hydrolysis in the cytoplasm to the periplasmic components of the system. However, our incomplete understanding of the assembly principles of the T2SS machinery prevents the mechanistic deconvolution of T2SS-mediated protein secretion. Here we show via two crystal structures that the periplasmic ferredoxin-like domain of GspL (GspLfld) is a dimer stabilized by hydrophobic interactions, and that this interface may allow significant interdomain plasticity. The general dimerization mode of GspLfld is shared with GspL from Vibrio parahaemolyticus suggesting a conserved oligomerization mode across the GspL family. Furthermore, we identified a tetrameric form of the complete periplasmic segment of GspL (GspLperi) which indicates that GspL may be able to adopt multiple oligomeric states as part of its dynamic role in the T2SS apparatus.
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Affiliation(s)
- Aleksandra Fulara
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, 9052, Ghent (Zwijnaarde), Belgium
- VIB-UGent Center for Inflammation Research, 9052, Ghent (Zwijnaarde), Belgium
| | - Isabel Vandenberghe
- Laboratory for Microbiology, Department of Biochemistry and Microbiology, Ghent University, 9000, Ghent, Belgium
| | - Randy J Read
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, United Kingdom
| | - Bart Devreese
- Laboratory for Microbiology, Department of Biochemistry and Microbiology, Ghent University, 9000, Ghent, Belgium
| | - Savvas N Savvides
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, 9052, Ghent (Zwijnaarde), Belgium.
- VIB-UGent Center for Inflammation Research, 9052, Ghent (Zwijnaarde), Belgium.
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11
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Michel-Souzy S, Douzi B, Cadoret F, Raynaud C, Quinton L, Ball G, Voulhoux R. Direct interactions between the secreted effector and the T2SS components GspL and GspM reveal a new effector-sensing step during type 2 secretion. J Biol Chem 2018; 293:19441-19450. [PMID: 30337370 DOI: 10.1074/jbc.ra117.001127] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 10/04/2018] [Indexed: 12/11/2022] Open
Abstract
In many Gram-negative bacteria, the type 2 secretion system (T2SS) plays an important role in virulence because of its capacity to deliver a large amount of fully folded protein effectors to the extracellular milieu. Despite our knowledge of most T2SS components, the mechanisms underlying effector recruitment and secretion by the T2SS remain enigmatic. Using complementary biophysical and biochemical approaches, we identified here two direct interactions between the secreted effector CbpD and two components, XcpYL and XcpZM, of the T2SS assembly platform (AP) in the opportunistic pathogen Pseudomonas aeruginosa Competition experiments indicated that CbpD binding to XcpYL is XcpZM-dependent, suggesting sequential recruitment of the effector by the periplasmic domains of these AP components. Using a bacterial two-hybrid system, we then tested the influence of the effector on the AP protein-protein interaction network. Our findings revealed that the presence of the effector modifies the AP interactome and, in particular, induces XcpZM homodimerization and increases the affinity between XcpYL and XcpZM The observed direct relationship between effector binding and T2SS dynamics suggests an additional synchronizing step during the type 2 secretion process, where the activation of the AP of the T2SS nanomachine is triggered by effector binding.
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Affiliation(s)
- Sandra Michel-Souzy
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France
| | - Badreddine Douzi
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France.,CNRS, Aix Marseille Université, IMM, Laboratoire de Chimie Bactérienne (LCB)/UMR7283, 13009 Marseille, France, and
| | - Frédéric Cadoret
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France
| | - Claire Raynaud
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France.,CNRS, Aix Marseille Université, IMM, Laboratoire de Chimie Bactérienne (LCB)/UMR7283, 13009 Marseille, France, and
| | - Loïc Quinton
- Laboratory of Mass Spectrometry-MolSys, Department of Chemistry, University of Liège, B4000 Liège, Belgium
| | - Geneviève Ball
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France.,CNRS, Aix Marseille Université, IMM, Laboratoire de Chimie Bactérienne (LCB)/UMR7283, 13009 Marseille, France, and
| | - Romé Voulhoux
- From the CNRS, Aix Marseille Université, Institut de Microbiologie de la Méditerranée (IMM), Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM)/UMR7255, 13009 Marseille, France, .,CNRS, Aix Marseille Université, IMM, Laboratoire de Chimie Bactérienne (LCB)/UMR7283, 13009 Marseille, France, and
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12
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Sharma G, Burrows LL, Singer M. Diversity and Evolution of Myxobacterial Type IV Pilus Systems. Front Microbiol 2018; 9:1630. [PMID: 30072980 PMCID: PMC6060248 DOI: 10.3389/fmicb.2018.01630] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 06/29/2018] [Indexed: 12/18/2022] Open
Abstract
Type IV pili (T4P) are surface-exposed protein fibers that play key roles in the bacterial life cycle via surface attachment/adhesion, biofilm formation, motility, and development. The order Myxococcales (myxobacteria) are members of the class Deltaproteobacteria and known for their large genome size and complex social behaviors, including gliding motility, fruiting body formation, biofilm production, and prey hunting. Myxococcus xanthus, the best-characterized member of the order, relies on the appropriate expression of 17 type IVa (T4aP) genes organized in a single cluster plus additional genes (distributed throughout the genome) for social motility and development. Here, we compared T4aP genes organization within the myxobacteria to understand their evolutionary origins and diversity. We found that T4aP genes are organized as large clusters in suborder Cystobacterineae, whereas in other two suborders Sorangiineae and Nannocystineae, these genes are dispersed throughout the genome. Based on the genomic organization, the phylogeny of conserved proteins, and synteny studies among 28 myxobacterial and 66 Proteobacterial genomes, we propose an evolutionary model for the origin of myxobacterial T4aP genes independently from other orders in class Deltaproteobacteria. Considering a major role for T4P, this study further proposes the origins and evolution of social motility in myxobacteria and provides a foundation for understanding how complex-behavioral traits, such as gliding motility, multicellular development, etc., might have evolved in this diverse group of complex organisms.
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Affiliation(s)
- Gaurav Sharma
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, United States
| | - Lori L Burrows
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, ON, Canada
| | - Mitchell Singer
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, United States
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13
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Curran CS, Bolig T, Torabi-Parizi P. Mechanisms and Targeted Therapies for Pseudomonas aeruginosa Lung Infection. Am J Respir Crit Care Med 2018; 197:708-727. [PMID: 29087211 PMCID: PMC5855068 DOI: 10.1164/rccm.201705-1043so] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 10/26/2017] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa is a complex gram-negative facultative anaerobe replete with a variety of arsenals to activate, modify, and destroy host defense mechanisms. The microbe is a common cause of nosocomial infections and an antibiotic-resistant priority pathogen. In the lung, P. aeruginosa disrupts upper and lower airway homeostasis by damaging the epithelium and evading innate and adaptive immune responses. The biology of these interactions is essential to understand P. aeruginosa pathogenesis. P. aeruginosa interacts directly with host cells via flagella, pili, lipoproteins, lipopolysaccharides, and the type III secretion system localized in the outer membrane. P. aeruginosa quorum-sensing molecules regulate the release of soluble factors that enhance the spread of infection. These characteristics of P. aeruginosa differentially affect lung epithelial, innate, and adaptive immune cells involved in the production of mediators and the recruitment of additional immune cell subsets. Pathogen interactions with individual host cells and in the context of host acute lung infection are discussed to reveal pathways that may be targeted therapeutically.
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Affiliation(s)
- Colleen S Curran
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Thomas Bolig
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Parizad Torabi-Parizi
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland
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14
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Leighton TL, Mok MC, Junop MS, Howell PL, Burrows LL. Conserved, unstructured regions in Pseudomonas aeruginosa PilO are important for type IVa pilus function. Sci Rep 2018; 8:2600. [PMID: 29422606 PMCID: PMC5805733 DOI: 10.1038/s41598-018-20925-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 01/25/2018] [Indexed: 02/04/2023] Open
Abstract
Pseudomonas aeruginosa uses long, thin fibres called type IV pili (T4P) for adherence to surfaces, biofilm formation, and twitching motility. A conserved subcomplex of PilMNOP is required for extension and retraction of T4P. To better understand its function, we attempted to co-crystallize the soluble periplasmic portions of PilNOP, using reductive surface methylation to promote crystal formation. Only PilOΔ109 crystallized; its structure was determined to 1.7 Å resolution using molecular replacement. This new structure revealed two novel features: a shorter N-terminal α1-helix followed by a longer unstructured loop, and a discontinuous β-strand in the second αββ motif, mirroring that in the first motif. PISA analysis identified a potential dimer interface with striking similarity to that of the PilO homolog EpsM from the Vibrio cholerae type II secretion system. We identified highly conserved residues within predicted unstructured regions in PilO proteins from various Pseudomonads and performed site-directed mutagenesis to assess their role in T4P function. R169D and I170A substitutions decreased surface piliation and twitching motility without disrupting PilO homodimer formation. These residues could form important protein-protein interactions with PilN or PilP. This work furthers our understanding of residues critical for T4aP function.
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Affiliation(s)
- T L Leighton
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - M C Mok
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada.,Department of Biochemistry, Western University, London, ON, Canada
| | - M S Junop
- Department of Biochemistry, Western University, London, ON, Canada
| | - P L Howell
- Program in Molecular Structure & Function, The Hospital for Sick Children, Toronto, ON, Canada. .,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
| | - L L Burrows
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada.
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15
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Gu S, Shevchik VE, Shaw R, Pickersgill RW, Garnett JA. The role of intrinsic disorder and dynamics in the assembly and function of the type II secretion system. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1255-1266. [PMID: 28733198 DOI: 10.1016/j.bbapap.2017.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/02/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
Many Gram-negative commensal and pathogenic bacteria use a type II secretion system (T2SS) to transport proteins out of the cell. These exported proteins or substrates play a major role in toxin delivery, maintaining biofilms, replication in the host and subversion of host immune responses to infection. We review the current structural and functional work on this system and argue that intrinsically disordered regions and protein dynamics are central for assembly, exo-protein recognition, and secretion competence of the T2SS. The central role of intrinsic disorder-order transitions in these processes may be a particular feature of type II secretion.
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Affiliation(s)
- Shuang Gu
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom
| | - Vladimir E Shevchik
- Université de Lyon, F-69003, Université Lyon 1, Lyon, F-69622, INSA-Lyon, Villeurbanne F-69621, CNRS, UMR5240, Microbiologie Adaptation et Pathogénie, Lyon F-69622, France
| | - Rosie Shaw
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom
| | - Richard W Pickersgill
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom.
| | - James A Garnett
- Queen Mary University of London, School of Biological and Chemical Sciences, London E1 4NS, United Kingdom.
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16
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Abstract
Type IVa pili (T4aP) are ubiquitous microbial appendages used for adherence, twitching motility, DNA uptake, and electron transfer. Many of these functions depend on dynamic assembly and disassembly of the pilus by a megadalton-sized, cell envelope-spanning protein complex located at the poles of rod-shaped bacteria. How the T4aP assembly complex becomes integrated into the cell envelope in the absence of dedicated peptidoglycan (PG) hydrolases is unknown. After ruling out the potential involvement of housekeeping PG hydrolases in the installation of the T4aP machinery in Pseudomonas aeruginosa, we discovered that key components of inner (PilMNOP) and outer (PilQ) membrane subcomplexes are recruited to future sites of cell division. Midcell recruitment of a fluorescently tagged alignment subcomplex component, mCherry-PilO, depended on PilQ secretin monomers—specifically, their N-terminal PG-binding AMIN domains. PilP, which connects PilO to PilQ, was required for recruitment, while PilM, which is structurally similar to divisome component FtsA, was not. Recruitment preceded secretin oligomerization in the outer membrane, as loss of the PilQ pilotin PilF had no effect on localization. These results were confirmed in cells chemically blocked for cell division prior to outer membrane invagination. The hub protein FimV and a component of the polar organelle coordinator complex—PocA—were independently required for midcell recruitment of PilO and PilQ. Together, these data suggest an integrated, energy-efficient strategy for the targeting and preinstallation—rather than retrofitting—of the T4aP system into nascent poles, without the need for dedicated PG-remodeling enzymes. The peptidoglycan (PG) layer of bacterial cell envelopes has limited porosity, representing a physical barrier to the insertion of large protein complexes involved in secretion and motility. Many systems include dedicated PG hydrolase components that create space for their insertion, but the ubiquitous type IVa pilus (T4aP) system lacks such an enzyme. Instead, we found that components of the T4aP system are recruited to future sites of cell division, where they could be incorporated into the cell envelope during the formation of new poles, eliminating the need for PG hydrolases. Targeting depends on the presence of septal PG-binding motifs in specific components, as removal of those motifs causes delocalization. This preinstallation strategy for the T4aP assembly system would ensure that both daughter cells are poised to extrude pili from new poles as soon as they separate from one another.
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