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Saran A, Kim HM, Manning I, Hancock MA, Schmitz C, Madej M, Potempa J, Sola M, Trempe JF, Zhu Y, Davey ME, Zeytuni N. Unveiling the molecular mechanisms of the type IX secretion system's response regulator: Structural and functional insights. PNAS NEXUS 2024; 3:pgae316. [PMID: 39139265 PMCID: PMC11320123 DOI: 10.1093/pnasnexus/pgae316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 07/22/2024] [Indexed: 08/15/2024]
Abstract
The type IX secretion system (T9SS) is a nanomachinery utilized by bacterial pathogens to facilitate infection. The system is regulated by a signaling cascade serving as its activation switch. A pivotal member in this cascade, the response regulator protein PorX, represents a promising drug target to prevent the secretion of virulence factors. Here, we provide a comprehensive characterization of PorX both in vitro and in vivo. First, our structural studies revealed PorX harbors a unique enzymatic effector domain, which, surprisingly, shares structural similarities with the alkaline phosphatase superfamily, involved in nucleotide and lipid signaling pathways. Importantly, such pathways have not been associated with the T9SS until now. Enzymatic characterization of PorX's effector domain revealed a zinc-dependent phosphodiesterase activity, with active site dimensions suitable to accommodate a large substrate. Unlike typical response regulators that dimerize via their receiver domain upon phosphorylation, we found that zinc can also induce conformational changes and promote PorX's dimerization via an unexpected interface. These findings suggest that PorX can serve as a cellular zinc sensor, broadening our understanding of its regulatory mechanisms. Despite the strict conservation of PorX in T9SS-utilizing bacteria, we demonstrate that PorX is essential for virulence factors secretion in Porphyromonas gingivalis and affects metabolic enzymes secretion in the nonpathogenic Flavobacterium johnsoniae, but not for the secretion of gliding adhesins. Overall, this study advances our structural and functional understanding of PorX, highlighting its potential as a druggable target for intervention strategies aimed at disrupting the T9SS and mitigating virulence in pathogenic species.
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Affiliation(s)
- Anshu Saran
- Department of Anatomy and Cell Biology, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
| | - Hey-Min Kim
- Department of Microbiology, The Forsyth Institute, 245 First St, Cambridge, MA 02142, USA
| | - Ireland Manning
- Department of Biological Sciences, Minnesota State University Mankato, 242 Trafton Science Center South, Mankato, MN 56001, USA
| | - Mark A Hancock
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
- Department of Pharmacology & Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC H3G 1Y6, Canada
| | - Claus Schmitz
- Department of Structural Biology, Molecular Biology Institute of Barcelona, Spanish Research Council, Barcelona Science Park, Barcelona E-08028, Spain
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków PL-30-387, Poland
| | - Jan Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków PL-30-387, Poland
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, 501 S Preston St, Louisville, KY 40202, USA
| | - Maria Sola
- Department of Structural Biology, Molecular Biology Institute of Barcelona, Spanish Research Council, Barcelona Science Park, Barcelona E-08028, Spain
| | - Jean-François Trempe
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
- Department of Pharmacology & Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC H3G 1Y6, Canada
| | - Yongtao Zhu
- Department of Biological Sciences, Minnesota State University Mankato, 242 Trafton Science Center South, Mankato, MN 56001, USA
- Department of Biological Sciences, Xi’an Jiaotong-Liverpool University, 111 Ren’ai Road, Suzhou Dushu Lake Science and Education Innovation District, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China
| | - Mary Ellen Davey
- Department of Microbiology, The Forsyth Institute, 245 First St, Cambridge, MA 02142, USA
| | - Natalie Zeytuni
- Department of Anatomy and Cell Biology, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
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Nakao R, Takatsuka A, Mandokoro K, Narisawa N, Ikeda T, Takai H, Ogata Y. Multimodal inhibitory effect of matcha on Porphyromonas gingivalis. Microbiol Spectr 2024; 12:e0342623. [PMID: 38771061 PMCID: PMC11218439 DOI: 10.1128/spectrum.03426-23] [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: 09/19/2023] [Accepted: 03/29/2024] [Indexed: 05/22/2024] Open
Abstract
Porphyromonas gingivalis has been associated with progression of periodontitis, characterized by inflammation and destruction of periodontal tissues. Here, we report that matcha, a product of Camellia sinensis, hampers the adherence and survival of P. gingivalis through multiple tactics. Matcha extract (ME) inhibited the growth not only of P. gingivalis but also of Prevotella nigrescens and Fusobacterium nucleatum, while it did not inhibit growth of nine species of oral streptococci and Aggregatibacter actinomycetemcomitans. ME-mediated P. gingivalis growth inhibition was characterized by both morphological and physiological changes at the bacterial envelope, which were accompanied by nano-particle formation and decreased membrane fluidity/permeability without loss of membrane integrity. ME also triggered autoaggregation of P. gingivalis in a major fimbriae (FimA)-dependent manner. In addition, adherence of P. gingivalis was dramatically inhibited by ME, irrespective of fimbriae. Furthermore, a structure-activity relationship study tested a series of catechins isolated from ME and identified the pyrogallol-type B-ring of catechins as essential for P. gingivalis growth inhibition. In a clinical study to assess the microbiological and therapeutic effects of matcha mouthwash in patients with periodontitis, the P. gingivalis number in saliva was significantly reduced by matcha mouthwash compared to the pre-intervention level. A tendency toward improvement in probing pocket depth was observed in the matcha group, although the difference was not statistically significant. Taken together, we present a proof of concept, based on the multimodal inhibitory effect of matcha against P. gingivalis, and that matcha may have clinical applicability for prevention and treatment of periodontitis. IMPORTANCE Periodontitis, a multifactorial inflammatory disease of the oral cavity, results in alveolar bone destruction, and is a major cause of tooth loss of humans. In addition, emerging evidence has demonstrated associations between periodontitis and a wide range of other chronic inflammation-driven disorders, including diabetes mellitus, preterm birth, cardiovascular disease, aspiration pneumonia, rheumatoid arthritis, cognitive disorder, and cancer. In the present study, we report that matcha, a product of Camellia sinensis, hampers Porphyromonas gingivalis, a major periodontal pathobiont, in not only a series of in vitro experiments but also a pilot intervention clinical trial of patients with periodontitis, in which matcha mouthwash statistically significantly reduced the P. gingivalis number in saliva, as compared to the pre-intervention level. Taken together, we suggest that matcha may have clinical applicability for prevention and treatment of periodontitis.
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Affiliation(s)
- Ryoma Nakao
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Ayami Takatsuka
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
- Department of Food Bioscience and Biotechnology, College of Bioresource Science, Nihon University, Kanagawa, Japan
| | - Kengo Mandokoro
- Department of Food Bioscience and Biotechnology, College of Bioresource Science, Nihon University, Kanagawa, Japan
| | - Naoki Narisawa
- Department of Food Bioscience and Biotechnology, College of Bioresource Science, Nihon University, Kanagawa, Japan
| | - Tsuyoshi Ikeda
- Department of Pharmaceutical Sciences, Sojo University, Kumamoto, Japan
| | - Hideki Takai
- Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan
| | - Yorimasa Ogata
- Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan
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Mizgalska D, Rodríguez-Banqueri A, Veillard F, Książęk M, Goulas T, Guevara T, Eckhard U, Potempa J, Gomis-Rüth FX. Structural and functional insights into the C-terminal signal domain of the Bacteroidetes type-IX secretion system. Open Biol 2024; 14:230448. [PMID: 38862016 DOI: 10.1098/rsob.230448] [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: 12/12/2023] [Accepted: 02/20/2024] [Indexed: 06/13/2024] Open
Abstract
Gram-negative bacteria from the Bacteroidota phylum possess a type-IX secretion system (T9SS) for protein secretion, which requires cargoes to have a C-terminal domain (CTD). Structurally analysed CTDs are from Porphyromonas gingivalis proteins RgpB, HBP35, PorU and PorZ, which share a compact immunoglobulin-like antiparallel 3+4 β-sandwich (β1-β7). This architecture is essential as a P. gingivalis strain with a single-point mutant of RgpB disrupting the interaction of the CTD with its preceding domain prevented secretion of the protein. Next, we identified the C-terminus ('motif C-t.') and the loop connecting strands β3 and β4 ('motif Lβ3β4') as conserved. We generated two strains with insertion and replacement mutants of PorU, as well as three strains with ablation and point mutants of RgpB, which revealed both motifs to be relevant for T9SS function. Furthermore, we determined the crystal structure of the CTD of mirolase, a cargo of the Tannerella forsythia T9SS, which shares the same general topology as in Porphyromonas CTDs. However, motif Lβ3β4 was not conserved. Consistently, P. gingivalis could not properly secrete a chimaeric protein with the CTD of peptidylarginine deiminase replaced with this foreign CTD. Thus, the incompatibility of the CTDs between these species prevents potential interference between their T9SSs.
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Affiliation(s)
- Danuta Mizgalska
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Arturo Rodríguez-Banqueri
- Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona (CSIC), Barcelona, Catalonia 08028, Spain
| | - Florian Veillard
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Mirosław Książęk
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Theodoros Goulas
- Department of Food Science and Nutrition, School of Agricultural Sciences, University of Thessaly, Karditsa 43100, Greece
| | - Tibisay Guevara
- Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona (CSIC), Barcelona, Catalonia 08028, Spain
| | - Ulrich Eckhard
- Synthetic Structural Biology Group, Department of Structural Biology, Molecular Biology Institute of Barcelona (CSIC), Barcelona, Catalonia 08028, Spain
| | - Jan Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY 40202, USA
| | - F Xavier Gomis-Rüth
- Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona (CSIC), Barcelona, Catalonia 08028, Spain
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Schmitz C, Madej M, Nowakowska Z, Cuppari A, Jacula A, Ksiazek M, Mikruta K, Wisniewski J, Pudelko-Malik N, Saran A, Zeytuni N, Mlynarz P, Lamont RJ, Usón I, Siksnys V, Potempa J, Solà M. Response regulator PorX coordinates oligonucleotide signalling and gene expression to control the secretion of virulence factors. Nucleic Acids Res 2022; 50:12558-12577. [PMID: 36464236 PMCID: PMC9757075 DOI: 10.1093/nar/gkac1103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/27/2022] [Accepted: 11/08/2022] [Indexed: 12/07/2022] Open
Abstract
The PglZ family of proteins belongs to the alkaline phosphatase superfamily, which consists of metallohydrolases with limited sequence identity but similar metal-coordination architectures in otherwise divergent active sites. Proteins with a well-defined PglZ domain are ubiquitous among prokaryotes as essential components of BREX phage defence systems and two-component systems (TCSs). Whereas other members of the alkaline phosphatase superfamily are well characterized, the activity, structure and biological function of PglZ family proteins remain unclear. We therefore investigated the structure and function of PorX, an orphan response regulator of the Porphyromonas gingivalis TCS containing a putative PglZ effector domain. The crystal structure of PorX revealed a canonical receiver domain, a helical bundle, and an unprecedented PglZ domain, similar to the general organization of the phylogenetically related BREX-PglZ proteins. The PglZ domain of PorX features an active site cleft suitable for large substrates. An extensive search for substrates revealed that PorX is a phosphodiesterase that acts on cyclic and linear oligonucleotides, including signalling molecules such as cyclic oligoadenylates. These results, combined with mutagenesis, biophysical and enzymatic analysis, suggest that PorX coordinates oligonucleotide signalling pathways and indirectly regulates gene expression to control the secretion of virulence factors.
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Affiliation(s)
- Claus Schmitz
- Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Barcelona E-08028, Spain
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
| | - Zuzanna Nowakowska
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
| | - Anna Cuppari
- Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Barcelona E-08028, Spain
| | - Anna Jacula
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
| | - Miroslaw Ksiazek
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
| | - Katarzyna Mikruta
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
| | - Jerzy Wisniewski
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw PL-50-370, Poland
| | - Natalia Pudelko-Malik
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw PL-50-370, Poland
| | - Anshu Saran
- Department of Anatomy and Cell Biology, McGill University, Montréal, Quebec H3A 0C7, Canada
| | - Natalie Zeytuni
- Department of Anatomy and Cell Biology, McGill University, Montréal, Quebec H3A 0C7, Canada
| | - Piotr Mlynarz
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw PL-50-370, Poland
| | - Richard J Lamont
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY 40202, USA
| | - Isabel Usón
- Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Barcelona E-08028, Spain
- ICREA Institució Catalana de Recerca i Estudis Avançats, Barcelona E-08010, Spain
| | - Virginijus Siksnys
- Institute of Biotechnology, Vilnius University, Vilnius 10257, Lithuania
| | - Jan Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków PL-30-387, Poland
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY 40202, USA
| | - Maria Solà
- Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Barcelona E-08028, Spain
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Phillips PL, Wu XJ, Reyes L. Differential affinity chromatography reveals a link between Porphyromonas gingivalis-induced changes in vascular smooth muscle cell differentiation and the type 9 secretion system. Front Cell Infect Microbiol 2022; 12:983247. [PMID: 36483452 PMCID: PMC9722745 DOI: 10.3389/fcimb.2022.983247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/24/2022] [Indexed: 11/23/2022] Open
Abstract
Porphyromonas gingivalis is implicated in adverse pregnancy outcome. We previously demonstrated that intrauterine infection with various strains of P. gingivalis impairs the physiologic remodeling of the uterine spiral arteries (IRSA) during pregnancy, which underlies the major obstetrical syndromes. Women diagnosed with IRSA also have a greater risk for premature cardiovascular disease in later life. The dysregulated plasticity of vascular smooth muscle cells (VSMCs) is present in both IRSA and premature cardiovascular events. We hypothesized that VSMCs could serve as a bait to identify P. gingivalis proteins associated with dysregulated VSMC plasticity as seen in IRSA. We first confirmed that dams with P. gingivalis A7UF-induced IRSA also show perturbed aortic smooth muscle cell (AoSMC) plasticity along with the P. gingivalis colonization of the tissue. The in vitro infection of AoSMCs with IRSA-inducing strain A7UF also perturbed AoSMC plasticity that did not occur with infection by non-IRSA-inducing strain W83. Far-Western blotting with strain W83 and strain A7UF showed a differential binding pattern to the rat aorta and primary rat AoSMCs. The affinity chromatography/pull-down assay combined with mass spectrometry was used to identify P. gingivalis/AoSMC protein interactions specific to IRSA. Membrane proteins with a high binding affinity to AoSMCs were identified in the A7UF pull-down but not in the W83 pull-down, most of which were the outer membrane components of the Type 9 secretion system (T9SS) and T9SS cargo proteins. Additional T9SS cargo proteins were detected in greater abundance in the A7UF pull-down eluate compared to W83. None of the proteins enriched in the W83 eluate were T9SS components nor T9SS cargo proteins despite their presence in the prey preparations used in the pull-down assay. In summary, differential affinity chromatography established that the components of IRSA-inducing P. gingivalis T9SS as well as its cargo directly interact with AoSMCs, which may play a role in the infection-induced dysregulation of VSMC plasticity. The possibility that the T9SS is involved in the microbial manipulation of host cell events important for cell differentiation and tissue remodeling would constitute a new virulence function for this system.
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Affiliation(s)
- Priscilla L. Phillips
- Microbiology and Immunology, A.T. Still University of Health Sciences, Kirksville College of Osteopathic Medicine, Kirksville, MO, United States
| | - Xiao-jun Wu
- Department of Pathobiological Sciences, University of Wisconsin - Madison, School of Veterinary Medicine, Madison, WI, United States
| | - Leticia Reyes
- Department of Pathobiological Sciences, University of Wisconsin - Madison, School of Veterinary Medicine, Madison, WI, United States,*Correspondence: Leticia Reyes,
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Protein Interactome Analysis of the Type IX Secretion System Identifies PorW as the Missing Link between the PorK/N Ring Complex and the Sov Translocon. Microbiol Spectr 2022; 10:e0160221. [PMID: 35019767 PMCID: PMC8754138 DOI: 10.1128/spectrum.01602-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The type IX secretion system (T9SS) transports cargo proteins through the outer membrane of Bacteroidetes and attaches them to the cell surface for functions including pathogenesis, gliding motility, and degradation of carbon sources. The T9SS comprises at least 20 different proteins and includes several modules: the trans-envelope core module comprising the PorL/M motor and the PorK/N ring, the outer membrane Sov translocon, and the cell attachment complex. However, the spatial organization of these modules is unknown. We have characterized the protein interactome of the Sov translocon in Porphyromonas gingivalis and identified Sov-PorV-PorA as well as Sov-PorW-PorN-PorK to be novel networks. PorW also interacted with PGN_1783 (PorD), which was required for maximum secretion efficiency. The identification of PorW as the missing link completes a continuous interaction network from the PorL/M motor to the Sov translocon, providing a pathway for cargo delivery and energy transduction from the inner membrane to the secretion pore. IMPORTANCE The T9SS is a newly identified protein secretion system of the Fibrobacteres-Chlorobi-Bacteroidetes superphylum used by pathogens associated with diseases of humans, fish, and poultry for the secretion and cell surface attachment of virulence factors. The T9SS comprises three known modules: (i) the trans-envelope core module comprising the PorL/M motor and the PorK/N ring, (ii) the outer membrane Sov translocon, and (iii) the cell surface attachment complex. The spatial organization and interaction of these modules have been a mystery. Here, we describe the protein interactome of the Sov translocon in the human pathogen Porphyromonas gingivalis and have identified PorW as the missing link which bridges PorN with Sov and so completes a continuous interaction network from the PorL/M motor to the Sov translocon, providing, for the first time, a pathway for cargo delivery and energy transduction from the inner membrane to the secretion pore.
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Veith PD, Glew MD, Gorasia DG, Cascales E, Reynolds EC. The Type IX Secretion System and Its Role in Bacterial Function and Pathogenesis. J Dent Res 2021; 101:374-383. [PMID: 34889148 DOI: 10.1177/00220345211051599] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Porphyromonas, Tannerella, and Prevotella species found in severe periodontitis use the Type IX Secretion System (T9SS) to load their outer membrane surface with an array of virulence factors. These virulence factors are then released on outer membrane vesicles (OMVs), which penetrate the host to dysregulate the immune response to establish a positive feedback loop of chronic, inflammatory destruction of the tooth's supporting tissues. In this review, we present the latest information on the molecular architecture of the T9SS and provide mechanistic insight into its role in secretion and attachment of cargo proteins to produce a virulence coat on cells and OMVs. The recent molecular structures of the T9SS motor comprising PorL and PorM as well as the secretion pore Sov, together with advances in the overall interactome, have provided insight into the possible mechanisms of secretion. We propose the presence of PorL/M motors arranged in a circle at the inner membrane with bent periplasmic rotors interacting with the PorN protein. At the outer membrane, we envisage a slide carousel model where the PorN protein is driven around a circular track composed of PorK. Cargo proteins are transported by PorN to PorW and the Sov translocon just as slides are rotated to the projection window. Secreted proteins are proposed to then be shuttled along highways consisting of the PorV shuttle protein to an array of attachment complexes distributed around the cell. The cell surface attachment of cargo is a hallmark of the T9SS, and in Porphyromonas gingivalis and Tannerella forsythia, this attachment is achieved via covalent bonding to a linking sugar synthesized by the Wbp/Vim pathway. The cell-surface attached cargo are enriched on OMVs, which are then released from the cell.
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Affiliation(s)
- P D Veith
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Victoria, Australia
| | - M D Glew
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Victoria, Australia
| | - D G Gorasia
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Victoria, Australia
| | - E Cascales
- Laboratoire d'Ingénierie des Syst èmes Macromol éculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), UMR7255, Marseille Cedex, France
| | - E C Reynolds
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Victoria, Australia
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Mizgalska D, Goulas T, Rodríguez-Banqueri A, Veillard F, Madej M, Małecka E, Szczesniak K, Ksiazek M, Widziołek M, Guevara T, Eckhard U, Solà M, Potempa J, Gomis-Rüth FX. Intermolecular latency regulates the essential C-terminal signal peptidase and sortase of the Porphyromonas gingivalis type-IX secretion system. Proc Natl Acad Sci U S A 2021; 118:e2103573118. [PMID: 34593635 PMCID: PMC8501833 DOI: 10.1073/pnas.2103573118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2021] [Indexed: 02/08/2023] Open
Abstract
Porphyromonas gingivalis is a keystone pathogen of the human dysbiotic oral microbiome that causes severe periodontitis. It employs a type-IX secretion system (T9SS) to shuttle proteins across the outer membrane (OM) for virulence. Uniquely, T9SS cargoes carry a C-terminal domain (CTD) as a secretion signal, which is cleaved and replaced with anionic lipopolysaccharide by transpeptidation for extracellular anchorage to the OM. Both reactions are carried out by PorU, the only known dual-function, C-terminal signal peptidase and sortase. PorU is itself secreted by the T9SS, but its CTD is not removed; instead, intact PorU combines with PorQ, PorV, and PorZ in the OM-inserted "attachment complex." Herein, we revealed that PorU transits between active monomers and latent dimers and solved the crystal structure of the ∼260-kDa dimer. PorU has an elongated shape ∼130 Å in length and consists of seven domains. The first three form an intertwined N-terminal cluster likely engaged in substrate binding. They are followed by a gingipain-type catalytic domain (CD), two immunoglobulin-like domains (IGL), and the CTD. In the first IGL, a long "latency β-hairpin" protrudes ∼30 Å from the surface to form an intermolecular β-barrel with β-strands from the symmetric CD, which is in a latent conformation. Homology modeling of the competent CD followed by in vivo validation through a cohort of mutant strains revealed that PorU is transported and functions as a monomer through a C690/H657 catalytic dyad. Thus, dimerization is an intermolecular mechanism for PorU regulation to prevent untimely activity until joining the attachment complex.
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Affiliation(s)
- Danuta Mizgalska
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Theodoros Goulas
- Proteolysis Laboratory, Department of Structural Biology, Higher Scientific Research Council (CSIC), Molecular Biology Institute of Barcelona, 08028 Barcelona, Catalonia, Spain
- Department of Food Science and Nutrition, School of Agricultural Sciences, University of Thessaly, 43100 Karditsa, Greece
| | - Arturo Rodríguez-Banqueri
- Proteolysis Laboratory, Department of Structural Biology, Higher Scientific Research Council (CSIC), Molecular Biology Institute of Barcelona, 08028 Barcelona, Catalonia, Spain
| | - Florian Veillard
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Ewelina Małecka
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Katarzyna Szczesniak
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Miroslaw Ksiazek
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Magda Widziołek
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
- Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, 30-387 Kraków, Poland
| | - Tibisay Guevara
- Proteolysis Laboratory, Department of Structural Biology, Higher Scientific Research Council (CSIC), Molecular Biology Institute of Barcelona, 08028 Barcelona, Catalonia, Spain
| | - Ulrich Eckhard
- Proteolysis Laboratory, Department of Structural Biology, Higher Scientific Research Council (CSIC), Molecular Biology Institute of Barcelona, 08028 Barcelona, Catalonia, Spain
| | - Maria Solà
- Structural MitoLab, Department of Structural Biology, Higher Scientific Research Council (CSIC), Molecular Biology Institute of Barcelona, 08028 Barcelona, Catalonia, Spain;
| | - Jan Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland;
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY 40202
| | - F Xavier Gomis-Rüth
- Proteolysis Laboratory, Department of Structural Biology, Higher Scientific Research Council (CSIC), Molecular Biology Institute of Barcelona, 08028 Barcelona, Catalonia, Spain;
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Lunar Silva I, Cascales E. Molecular Strategies Underlying Porphyromonas gingivalis Virulence. J Mol Biol 2021; 433:166836. [PMID: 33539891 DOI: 10.1016/j.jmb.2021.166836] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/15/2021] [Accepted: 01/15/2021] [Indexed: 02/07/2023]
Abstract
The anaerobic Gram-negative bacterium Porphyromonas gingivalis is considered the keystone of periodontitis diseases, a set of inflammatory conditions that affects the tissues surrounding the teeth. In the recent years, the major virulence factors exploited by P. gingivalis have been identified and characterized, including a cocktail of toxins, mainly proteases called gingipains, which promote gingival tissue invasion. These effectors use the Sec pathway to cross the inner membrane and are then recruited and transported across the outer membrane by the type IX secretion system (T9SS). In P. gingivalis, most secreted effectors are attached to anionic lipopolysaccharides (A-LPS), and hence form a virulence coat at the cell surface. P. gingivalis produces additional virulence factors to evade host immune responses, such as capsular polysaccharide, fimbriae and outer membrane vesicles. In addition to periodontitis, it is proposed that this broad repertoire of virulence factors enable P. gingivalis to be involved in diverse human diseases such as rheumatoid arthritis, and neurodegenerative, Alzheimer, and cardiovascular disorders. Here, we review the major virulence determinants of P. gingivalis and discuss future directions to better understand their mechanisms of action.
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Affiliation(s)
- Ignacio Lunar Silva
- Laboratoire d'Ingénierie des Syst èmes Macromol éculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), UMR7255, 31 Chemin Joseph Aiguier CS7071, 13009 Marseille Cedex 20, France.
| | - Eric Cascales
- Laboratoire d'Ingénierie des Syst èmes Macromol éculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), UMR7255, 31 Chemin Joseph Aiguier CS7071, 13009 Marseille Cedex 20, France.
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