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Whitfield GB, Brun YV. The type IVc pilus: just a Tad different. Curr Opin Microbiol 2024; 79:102468. [PMID: 38579360 DOI: 10.1016/j.mib.2024.102468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/12/2024] [Accepted: 03/14/2024] [Indexed: 04/07/2024]
Abstract
Bacteria utilize type IV pili (T4P) to interact with their environment, where they facilitate processes including motility, adherence, and DNA uptake. T4P require multisubunit, membrane-spanning nanomachines for assembly. The tight adherence (Tad) pili are an Archaea-derived T4P subgroup whose machinery exhibits significant mechanistic and architectural differences from bacterial type IVa and IVb pili. Most Tad biosynthetic genes are encoded in a single locus that is widespread in bacteria due to facile acquisition via horizontal gene transfer. These loci experience extensive structural rearrangements, including the acquisition of novel regulatory or biosynthetic genes, which fine-tune their function. This has permitted their integration into many different bacterial lifestyles, including the Caulobacter crescentus cell cycle, Myxococcus xanthus predation, and numerous plant and mammalian pathogens and symbionts.
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Affiliation(s)
- Gregory B Whitfield
- Département de Microbiologie, Infectiologie, et Immunologie, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, Québec H3C 3J7, Canada.
| | - Yves V Brun
- Département de Microbiologie, Infectiologie, et Immunologie, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, Québec H3C 3J7, Canada
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2
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Bhattacharyya A, Banerjee G, Chattopadhyay P. Probable Role of Type IV Pili of Aeromonas hydrophila in Human Pathogenicity. Pathogens 2024; 13:365. [PMID: 38787217 PMCID: PMC11124393 DOI: 10.3390/pathogens13050365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 04/15/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Aeromonas hydrophila is a widely recognized broad-spectrum pathogen that primarily targets the gastrointestinal tract. Type IV pili (T4P) are proteinaceous nano-machines located on the bacterial cell surface, playing a crucial role in host colonization and infection. Regrettably, the T4P systems of A. hydrophila remain largely underexplored. METHODS A. hydrophila genomes with complete genome assembly and annotation reports up to 31 March 2023, were obtained from the NCBI Genome database or KEGG genome database, followed by a global search for T4P secretion system genes. Protein sequences of these manually curetted genes were used as secondary quarry for Synteny analysis. Protein-protein interaction analysis was performed by string analysis and in silico study of genomic islands. RESULTS We identified 27 orthologs of type IV pili (T4P) nano-machine components in A. hydrophila. These orthologs are primarily distributed across three operons: pilABCD, pilMNOPQ, and pilVWXY. While the first two operons are commonly found in all experimental genomes, the presence of the pilVWXY operon, coding for 11 orthologs, is reported here for the first time in A. hydrophila. Notably, the complete pilVWXY operon is absent in nonvirulent strains. A genomic islands study between a nonvirulent and hypervirulent strain also confirms absence of most of the genes coded by pilVWXY in nonvirulent strain. Interestingly, among the 51 experimental genomes analyzed, the pilVWXY operon was completely absent in 10 strains, most of which are categorized as nonvirulent; Conclusions: The distribution of two major type IV pili (T4P) nano-machines, PilABCDMNOPQ and PilVWXY, is reported here for the first time in A. hydrophila. Additionally, this study suggests a potential role for the PilVWXY nano-machine in establishing human disease.
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Affiliation(s)
- Agradip Bhattacharyya
- Raja Rammohun Roy Mahavidyalaya, Radhanagar, Nangulpara, Hooghly, West Bengal 712406, India;
| | - Goutam Banerjee
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Mom J, Chouikha I, Valette O, Pieulle L, Pelicic V. Systematic functional analysis of the Com pilus in Streptococcus sanguinis: a minimalistic type 4 filament dedicated to DNA uptake in monoderm bacteria. mBio 2024; 15:e0266723. [PMID: 38095871 PMCID: PMC10790768 DOI: 10.1128/mbio.02667-23] [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: 09/29/2023] [Accepted: 11/07/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE Type 4 filaments (T4F) are nanomachines ubiquitous in prokaryotes, centered on filamentous polymers of type 4 pilins. T4F are exceptionally versatile and widespread virulence factors in bacterial pathogens. The mechanisms of filament assembly and the many functions they facilitate remain poorly understood because of the complexity of T4F machineries. This hinders the development of anti-T4F drugs. The significance of our research lies in characterizing the simplest known T4F-the Com pilus that mediates DNA uptake in competent monoderm bacteria-and showing that four protein components universally conserved in T4F are sufficient for filament assembly. The Com pilus becomes a model for elucidating the mechanisms of T4F assembly.
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Affiliation(s)
- Jeremy Mom
- Laboratoire de Chimie Bactérienne, Aix-Marseille Université-CNRS (UMR 7283), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Iman Chouikha
- Laboratoire de Chimie Bactérienne, Aix-Marseille Université-CNRS (UMR 7283), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Odile Valette
- Laboratoire de Chimie Bactérienne, Aix-Marseille Université-CNRS (UMR 7283), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Laetitia Pieulle
- Laboratoire de Chimie Bactérienne, Aix-Marseille Université-CNRS (UMR 7283), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Vladimir Pelicic
- Laboratoire de Chimie Bactérienne, Aix-Marseille Université-CNRS (UMR 7283), Institut de Microbiologie de la Méditerranée, Marseille, France
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Anger R, Pieulle L, Shahin M, Valette O, Le Guenno H, Kosta A, Pelicic V, Fronzes R. Structure of a heteropolymeric type 4 pilus from a monoderm bacterium. Nat Commun 2023; 14:7143. [PMID: 37932265 PMCID: PMC10628169 DOI: 10.1038/s41467-023-42872-5] [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: 06/15/2023] [Accepted: 10/24/2023] [Indexed: 11/08/2023] Open
Abstract
Type 4 pili (T4P) are important virulence factors, which belong to a superfamily of nanomachines ubiquitous in prokaryotes, called type 4 filaments (T4F). T4F are defined as helical polymers of type 4 pilins. Recent advances in cryo-electron microscopy (cryo-EM) led to structures of several T4F, revealing that the long N-terminal α-helix (α1) - the trademark of pilins - packs in the centre of the filaments to form a hydrophobic core. In diderm bacteria - all available bacterial T4F structures are from diderm species - a portion of α1 is melted (unfolded). Here we report that this architecture is conserved in phylogenetically distant monoderm species by determining the structure of Streptococcus sanguinis T4P. Our 3.7 Å resolution cryo-EM structure of S. sanguinis heteropolymeric T4P and the resulting full atomic model including all minor pilins highlight universal features of bacterial T4F and have widespread implications in understanding T4F biology.
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Affiliation(s)
- Robin Anger
- Institut Européen de Chimie et Biologie, Université de Bordeaux-CNRS (UMR 5234), Pessac, France
| | - Laetitia Pieulle
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS (UMR 7283), Marseille, France
| | - Meriam Shahin
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Odile Valette
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS (UMR 7283), Marseille, France
| | - Hugo Le Guenno
- Plateforme de Microscopie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, Marseille, France
| | - Artemis Kosta
- Plateforme de Microscopie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, Marseille, France
| | - Vladimir Pelicic
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS (UMR 7283), Marseille, France.
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK.
| | - Rémi Fronzes
- Institut Européen de Chimie et Biologie, Université de Bordeaux-CNRS (UMR 5234), Pessac, France.
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Kint N, Viollier PH. Extracellular transfer of a conserved polymerization factor for multi-flagellin filament assembly in Caulobacter. Cell Rep 2023; 42:112890. [PMID: 37515768 DOI: 10.1016/j.celrep.2023.112890] [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: 12/12/2022] [Revised: 06/15/2023] [Accepted: 07/12/2023] [Indexed: 07/31/2023] Open
Abstract
Unidirectional growth of filamentous protein assemblies including the bacterial flagellum relies on dedicated polymerization factors (PFs). The molecular determinants and structural transitions imposed by PFs on multi-subunit assembly are poorly understood. Here, we unveil FlaY from the polarized α-proteobacterium Caulobacter crescentus as a defining member of an alternative class of specialized flagellin PFs. Unlike the paradigmatic FliD capping protein, FlaY relies on a funnel-like β-propeller fold for flagellin polymerization. FlaY binds flagellin and is secreted by the flagellar secretion apparatus, yet it can also promote flagellin polymerization exogenously when donated from flagellin-deficient cells, serving as a transferable, extracellular public good. While the surge in FlaY abundance precedes bulk flagellin synthesis, FlaY-independent filament assembly is enhanced by mutation of a conserved region in multiple flagellin paralogs. We suggest that FlaYs are (multi-)flagellin PFs that evolved convergently to FliDs yet appropriated the versatile β-propeller fold implicated in human diseases for chaperone-assisted filament assembly.
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Affiliation(s)
- Nicolas Kint
- Department of Microbiology & Molecular Medicine and Geneva Center for Inflammation Research (GCIR), Faculty of Medicine, University of Geneva, Rue Michel Servet 1, 1211 Genève, Switzerland.
| | - Patrick H Viollier
- Department of Microbiology & Molecular Medicine and Geneva Center for Inflammation Research (GCIR), Faculty of Medicine, University of Geneva, Rue Michel Servet 1, 1211 Genève, Switzerland.
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Song HC, Yang YX, Lan QG, Cong W. Immunological effects of recombinant Lactobacillus casei expressing pilin MshB fused with cholera toxin B subunit adjuvant as an oral vaccine against Aeromonas veronii infection in crucian carp. FISH & SHELLFISH IMMUNOLOGY 2023:108934. [PMID: 37419434 DOI: 10.1016/j.fsi.2023.108934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/08/2023] [Accepted: 07/03/2023] [Indexed: 07/09/2023]
Abstract
Aeromonas veronii is a zoonotic agent capable of infecting fish and mammals, including humans, posing a serious threat to the development of aquaculture and public health safety. Currently, few effective vaccines are available through convenient routes against A. veronii infection. Herein, we developed vaccine candidates by inserting MSH type VI pili B (MshB) from A. veronii as an antigen and cholera toxin B subunit (CTB) as a molecular adjuvant into Lactobacillus casei and evaluated their immunological effect as vaccines in a crucian carp (Carassius auratus) model. The results suggested that recombinant L. casei Lc-pPG-MshB and Lc-pPG-MshB-CTB can be stably inherited for more than 50 generations. Oral administration of recombinant L. casei vaccine candidates stimulated the production of high levels of serum-specific immunoglobulin M (IgM) and increased the activity of acid phosphatase (ACP), alkaline phosphatase (AKP) superoxide dismutase (SOD), lysozyme (LZM), complement 3 (C3) and C4 in crucian carp (carassius auratus) compared to the control group (Lc-pPG612 group and PBS group) without significant changes. Moreover, the expression levels of interleukin-10 (IL-10), interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) genes in the gills, liver, spleen, kidney and gut of crucian carp orally immunized with recombinant L. casei were significantly upregulated compared to the control groups, indicating that recombinant L. casei induced a significant cellular immune response. In addition, viable recombinant L. casei can be detected and stably colonized in the intestine tract of crucian carp. Particularly, crucian carp immunized orally with Lc-pPG-MshB and Lc-pPG-MshB-CTB exhibited higher survival rates (48% for Lc-pPG-MshB and 60% for Lc-pPG-MshB-CTB) and significantly reduced loads of A. veronii in the major immune organs after A. veronii challenge. Our findings indicated that both recombinant L. casei strains provide favorable immune protection, with Lc-pPG-MshB-CTB in particular being more effective and promising as an ideal candidate for oral vaccination.
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Affiliation(s)
- Hai-Chao Song
- Marine College, Shandong University, Weihai, Shandong Province, 264209, PR China
| | - Yi-Xuan Yang
- College of Veterinary Medicine, College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, PR China
| | - Qi-Guan Lan
- College of Veterinary Medicine, College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, PR China
| | - Wei Cong
- Marine College, Shandong University, Weihai, Shandong Province, 264209, PR China.
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Treerat P, Anderson D, Giacaman RA, Merritt J, Kreth J. Glycerol metabolism supports oral commensal interactions. THE ISME JOURNAL 2023:10.1038/s41396-023-01426-9. [PMID: 37169870 DOI: 10.1038/s41396-023-01426-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 04/19/2023] [Accepted: 04/27/2023] [Indexed: 05/13/2023]
Abstract
During oral biofilm development, interspecies interactions drive species distribution and biofilm architecture. To understand what molecular mechanisms determine these interactions, we used information gained from recent biogeographical investigations demonstrating an association of corynebacteria with streptococci. We previously reported that Streptococcus sanguinis and Corynebacterium durum have a close relationship through the production of membrane vesicle and fatty acids leading to S. sanguinis chain elongation and overall increased fitness supporting their commensal state. Here we present the molecular mechanisms of this interspecies interaction. Coculture experiments for transcriptomic analysis identified several differentially expressed genes in S. sanguinis. Due to its connection to fatty acid synthesis, we focused on the glycerol-operon. We further explored the differentially expressed type IV pili genes due to their connection to motility and biofilm adhesion. Gene inactivation of the glycerol kinase glpK had a profound impact on the ability of S. sanguinis to metabolize C. durum secreted glycerol and impaired chain elongation important for their interaction. Investigations on the effect of type IV pili revealed a reduction of S. sanguinis twitching motility in the presence of C. durum, which was caused by a decrease in type IV pili abundance on the surface of S. sanguinis as determined by SEM. In conclusion, we identified that the ability to metabolize C. durum produced glycerol is crucial for the interaction of C. durum and S. sanguinis. Reduced twitching motility could lead to a closer interaction of both species, supporting niche development in the oral cavity and potentially shaping symbiotic health-associated biofilm communities.
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Affiliation(s)
- Puthayalai Treerat
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University (OHSU), Portland, OR, 97239, USA.
| | - David Anderson
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University (OHSU), Portland, OR, 97239, USA
| | - Rodrigo A Giacaman
- Cariology Unit, Department of Oral Rehabilitation, Faculty of Dentistry, University of Talca, Talca, Chile
| | - Justin Merritt
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University (OHSU), Portland, OR, 97239, USA
- Department of Molecular Microbiology and Immunology, School of Medicine, Oregon Health & Science University (OHSU), Portland, OR, 97239, USA
| | - Jens Kreth
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University (OHSU), Portland, OR, 97239, USA.
- Department of Molecular Microbiology and Immunology, School of Medicine, Oregon Health & Science University (OHSU), Portland, OR, 97239, USA.
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8
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Pelicic V. Mechanism of assembly of type 4 filaments: everything you always wanted to know (but were afraid to ask). MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 36947586 DOI: 10.1099/mic.0.001311] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Type 4 filaments (T4F) are a superfamily of filamentous nanomachines - virtually ubiquitous in prokaryotes and functionally versatile - of which type 4 pili (T4P) are the defining member. T4F are polymers of type 4 pilins, assembled by conserved multi-protein machineries. They have long been an important topic for research because they are key virulence factors in numerous bacterial pathogens. Our poor understanding of the molecular mechanisms of T4F assembly is a serious hindrance to the design of anti-T4F therapeutics. This review attempts to shed light on the fundamental mechanistic principles at play in T4F assembly by focusing on similarities rather than differences between several (mostly bacterial) T4F. This holistic approach, complemented by the revolutionary ability of artificial intelligence to predict protein structures, led to an intriguing mechanistic model of T4F assembly.
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Affiliation(s)
- Vladimir Pelicic
- Laboratoire de Chimie Bactérienne, UMR 7283 CNRS/Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, Marseille, France
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9
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Islam ST, Jolivet NY, Cuzin C, Belgrave AM, My L, Fleuchot B, Faure LM, Mahanta U, Kezzo AA, Saïdi F, Sharma G, Fiche JB, Bratton BP, Herrou J, Nollmann M, Shaevitz JW, Durand E, Mignot T. Unmasking of the von Willebrand A-domain surface adhesin CglB at bacterial focal adhesions mediates myxobacterial gliding motility. SCIENCE ADVANCES 2023; 9:eabq0619. [PMID: 36812310 PMCID: PMC9946355 DOI: 10.1126/sciadv.abq0619] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
The predatory deltaproteobacterium Myxococcus xanthus uses a helically-trafficked motor at bacterial focal-adhesion (bFA) sites to power gliding motility. Using total internal reflection fluorescence and force microscopies, we identify the von Willebrand A domain-containing outer-membrane (OM) lipoprotein CglB as an essential substratum-coupling adhesin of the gliding transducer (Glt) machinery at bFAs. Biochemical and genetic analyses reveal that CglB localizes to the cell surface independently of the Glt apparatus; once there, it is recruited by the OM module of the gliding machinery, a heteroligomeric complex containing the integral OM β barrels GltA, GltB, and GltH, as well as the OM protein GltC and OM lipoprotein GltK. This Glt OM platform mediates the cell-surface accessibility and retention of CglB by the Glt apparatus. Together, these data suggest that the gliding complex promotes regulated surface exposure of CglB at bFAs, thus explaining the manner by which contractile forces exerted by inner-membrane motors are transduced across the cell envelope to the substratum.
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Affiliation(s)
- Salim T. Islam
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, QC H7V 1B7, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Laval, QC G1V 0A6, Canada
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Nicolas Y. Jolivet
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, QC H7V 1B7, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Laval, QC G1V 0A6, Canada
| | - Clémence Cuzin
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Akeisha M. Belgrave
- Integrated Sciences Program, Harrisburg University of Science and Technology, Harrisburg, PA 17101, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
| | - Laetitia My
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Betty Fleuchot
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Laura M. Faure
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Utkarsha Mahanta
- Institute of Bioinformatics and Applied Biotechnology, Electronic City, Bengaluru-560100, Karnataka, India
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana-502284, India
| | - Ahmad A. Kezzo
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, QC H7V 1B7, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Laval, QC G1V 0A6, Canada
| | - Fares Saïdi
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, QC H7V 1B7, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Laval, QC G1V 0A6, Canada
| | - Gaurav Sharma
- Institute of Bioinformatics and Applied Biotechnology, Electronic City, Bengaluru-560100, Karnataka, India
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana-502284, India
| | - Jean-Bernard Fiche
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, 34090 Montpellier, France
| | - Benjamin P. Bratton
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN 37232, USA
| | - Julien Herrou
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Marcelo Nollmann
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, 34090 Montpellier, France
| | - Joshua W. Shaevitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
| | - Eric Durand
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
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Characterization of a glycan-binding complex of minor pilins completes the analysis of Streptococcus sanguinis type 4 pili subunits. Proc Natl Acad Sci U S A 2023; 120:e2216237120. [PMID: 36626560 PMCID: PMC9934059 DOI: 10.1073/pnas.2216237120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Type 4 filaments (T4F)-of which type 4 pili (T4P) are the archetype-are a superfamily of nanomachines nearly ubiquitous in prokaryotes. T4F are polymers of one major pilin, which also contain minor pilins whose roles are often poorly understood. Here, we complete the structure/function analysis of the full set of T4P pilins in the opportunistic bacterial pathogen Streptococcus sanguinis. We determined the structure of the minor pilin PilA, which is unexpectedly similar to one of the subunits of a tip-located complex of four minor pilins, widely conserved in T4F. We found that PilA interacts and dramatically stabilizes the minor pilin PilC. We determined the structure of PilC, showing that it is a modular pilin with a lectin module binding a subset of glycans prevalent in the human glycome, the host of S. sanguinis. Altogether, our findings support a model whereby the minor pilins in S. sanguinis T4P form a tip-located complex promoting adhesion to various host receptors. This has general implications for T4F.
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11
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Ronish LA, Sidner B, Yu Y, Piepenbrink KH. Recognition of extracellular DNA by type IV pili promotes biofilm formation by Clostridioides difficile. J Biol Chem 2022; 298:102449. [PMID: 36064001 PMCID: PMC9556784 DOI: 10.1016/j.jbc.2022.102449] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 11/15/2022] Open
Abstract
Clostridioides difficile is a Gram-positive bacillus, which is a frequent cause of gastrointestinal infections triggered by the depletion of the gut microbiome. Because of the frequent recurrence of these infections after antibiotic treatment, mechanisms of C. difficile persistence and recurrence, including biofilm formation, are of increasing interest. Previously, our group and others found that type IV pili, filamentous helical appendages polymerized from protein subunits, promoted microcolony and biofilm formation in C. difficile. In Gram-negative bacteria, the ability of type IV pili to mediate bacterial self-association has been explained through interactions between the pili of adjacent cells, but type IV pili from several Gram-negative species are also required for natural competence through DNA uptake. Here, we report the ability of two C. difficile pilin subunits, PilJ and PilW, to bind to DNA in vitro, as well as the defects in biofilm formation in the pilJ and pilW gene-interruption mutants. Additionally, we have resolved the X-ray crystal structure of PilW, which we use to model possible structural mechanisms for the formation of C. difficile biofilm through interactions between type IV pili and the DNA of the extracellular matrix. Taken together, our results provide further insight into the relationship between type IV pilus function and biofilm formation in C. difficile and, more broadly, suggest that DNA recognition by type IV pili and related structures may have functional importance beyond DNA uptake for natural competence.
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Affiliation(s)
- Leslie A Ronish
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Ben Sidner
- Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Yafan Yu
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA; Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Kurt H Piepenbrink
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA; Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA; Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA; Nebraska Food for Health Center, University of Nebraska-Lincoln, Lincoln, Nebraska, USA; Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, Nebraska, USA.
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12
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Prevalence of Type IV Pili-Mediated Twitching Motility in Streptococcus sanguinis Strains and Its Impact on Biofilm Formation and Host Adherence. Appl Environ Microbiol 2022; 88:e0140322. [PMID: 36094177 PMCID: PMC9499025 DOI: 10.1128/aem.01403-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Type IV pili (Tfp) are known to mediate several biological activities, including surface-dependent twitching motility. Although a pil gene cluster for Tfp biosynthesis is found in all sequenced Streptococcus sanguinis strains, Tfp-mediated twitching motility is less commonly detected. Upon examining 81 clinical strains, 39 strains generated twitching zones on blood agar plates (BAP), while 27 strains displayed twitching on Todd-Hewitt (TH) agar. Although BAP appears to be more suitable for the development of twitching zones, 5 strains exhibited twitching motility only on TH agar, indicating that twitching motility is not only strain specific but also sensitive to growth media. Furthermore, different twitching phenotypes were observed in strains expressing comparable levels of pilT, encoding the retraction ATPase, suggesting that the twitching phenotype on agar plates is regulated by multiple factors. By using a PilT-null and a pilin protein-null derivative (CHW02) of twitching-active S. sanguinis CGMH010, we found that Tfp retraction was essential for biofilm stability. Further, biofilm growth was amplified in CHW02 in the absence of shearing force, indicating that S. sanguinis may utilize other ligands for biofilm formation in the absence of Tfp. Similar to SK36, Tfp from CGMH010 were required for colonization of host cells, but PilT only marginally affected adherence and only in the twitching-active strain. Taken together, the results suggest that Tfp participates in host cell adherence and that Tfp retraction facilitates biofilm stability. IMPORTANCE Although the gene clusters encoding Tfp are commonly present in Streptococcus sanguinis, not all strains express surface-dependent twitching motility on agar surfaces. Regardless of whether the Tfp could drive motility, Tfp can serve as a ligand for the colonization of host cells. Though many S. sanguinis strains lack twitching activity, motility can enhance biofilm stability in a twitching-active strain; thus, perhaps motility provides little or no advantage to the survival of bacteria within dental plaque. Rather, Tfp retraction could provide additional advantages for the bacteria to establish infections outside the oral cavity.
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13
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Yadav RK, Krishnan V. New structural insights into the
PI
‐2 pilus from
Streptococcus oralis
, an early dental plaque colonizer. FEBS J 2022; 289:6342-6366. [DOI: 10.1111/febs.16527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 04/20/2022] [Accepted: 05/10/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Rajnesh Kumari Yadav
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology NCR Biotech Science Cluster Faridabad India
- School of Biotechnology KIIT University Odisha India
| | - Vengadesan Krishnan
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology NCR Biotech Science Cluster Faridabad India
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14
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Type IV Pili of Streptococcus sanguinis Contribute to Pathogenesis in Experimental Infective Endocarditis. Microbiol Spectr 2021; 9:e0175221. [PMID: 34756087 PMCID: PMC8579931 DOI: 10.1128/spectrum.01752-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus sanguinis is a common cause of infective endocarditis (IE). Efforts by research groups are aimed at identifying and characterizing virulence factors that contribute to the ability of this organism to cause IE. This Gram-positive pathogen causes heart infection by gaining access to the bloodstream, adhering to host extracellular matrix protein and/or platelets, colonizing the aortic endothelium, and incorporating itself into the aortic vegetation. While many virulence factors have been reported to contribute to the ability of S. sanguinis to cause IE, it is noteworthy that type IV pili (T4P) have not been described to be a virulence factor in this organism, although S. sanguinis strains typically encode these pili. Type IV pili are molecular machines that are capable of mediating diverse virulence functions and surface motility. T4P have been shown to mediate twitching motility in some strains of S. sanguinis, although in most strains it has been difficult to detect twitching motility. While we found that T4P are dispensable for direct in vitro platelet binding and aggregation phenotypes, we show that they are critical to the development of platelet-dependent biofilms representative of the cardiac vegetation. We also observed that T4P are required for in vitro invasion of S. sanguinis into human aortic endothelial cells, which indicates that S. sanguinis may use T4P to take advantage of an intracellular niche during infection. Importantly, we show that T4P of S. sanguinis are critical to disease progression (vegetation development) in a native valve IE rabbit model. The results presented here expand our understanding of IE caused by S. sanguinis and identify T4P as an important virulence factor for this pathogen. IMPORTANCE This work provides evidence that type IV pili produced by Streptococcus sanguinis SK36 are critical to the ability of these bacteria to attach to and colonize the aortic heart valve (endocarditis). We found that an S. sanguinis type IV pili mutant strain was defective in causing platelet-dependent aggregation in a 24-h infection assay but not in a 1-h platelet aggregation assay, suggesting that the type IV pili act at later stages of vegetation development. In a rabbit model of disease, a T4P mutant strain does not develop mature vegetations that form on the heart, indicating that this virulence factor is critical to disease and could be a target for IE therapy.
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15
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Abstract
During biofilm formation, the opportunistic pathogen Pseudomonas aeruginosa uses its type IV pili (TFP) to sense a surface, eliciting increased second-messenger production and regulating target pathways required to adapt to a surface lifestyle. The mechanisms whereby TFP detect surface contact are still poorly understood, although mechanosensing is often invoked, with few data supporting this claim. Using a combination of molecular genetics and single-cell analysis, with biophysical, biochemical, and genomics techniques, we show that force-induced changes mediated by the von Willebrand A (vWA) domain-containing, TFP tip-associated protein PilY1 are required for surface sensing. Atomic force microscopy shows that TFP/PilY1 can undergo force-induced, sustained conformational changes akin to those observed for mechanosensitive proteins like titin. We show that mutation of a single cysteine residue in the vWA domain of PilY1 results in modestly lower surface adhesion forces, reduced sustained conformational changes, and increased nanospring-like properties, as well as reduced c-di-GMP signaling and biofilm formation. Mutating this cysteine has allowed us to genetically separate a role for TFP in twitching motility from surface-sensing signaling. The conservation of this Cys residue in all P. aeruginosa PA14 strains and its absence in the ∼720 sequenced strains of P. aeruginosa PAO1 may contribute to explaining the observed differences in surface colonization strategies observed for PA14 versus PAO1. IMPORTANCE Most bacteria live on abiotic and biotic surfaces in surface-attached communities known as biofilms. Surface sensing and increased levels of the second-messenger molecule c-di-GMP are crucial to the transition from planktonic to biofilm growth. The mechanism(s) underlying TFP-mediated surface detection that triggers this c-di-GMP signaling cascade is unclear. Here, we provide key insight into this question; we show that the eukaryote-like vWA domain of the TFP tip-associated protein PilY1 responds to mechanical force, which in turn drives the production of a key second messenger needed to regulate surface behaviors. Our studies highlight a potential mechanism that may account for differing surface colonization strategies.
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