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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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2
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Pham C, Guo S, Han X, Coleman L, Sze CW, Wang H, Liu J, Li C. A pleiotropic role of sialidase in the pathogenicity of Porphyromonas gingivalis. Infect Immun 2024; 92:e0034423. [PMID: 38376159 PMCID: PMC10929438 DOI: 10.1128/iai.00344-23] [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: 01/02/2024] [Accepted: 02/01/2024] [Indexed: 02/21/2024] Open
Abstract
As one of the keystone pathogens of periodontitis, the oral bacterium Porphyromonas gingivalis produces an array of virulence factors, including a recently identified sialidase (PG0352). Our previous report involving loss-of-function studies indicated that PG0352 plays an important role in the pathophysiology of P. gingivalis. However, this report had not been corroborated by gain-of-function studies or substantiated in different P. gingivalis strains. To fill these gaps, herein we first confirm the role of PG0352 in cell surface structures (e.g., capsule) and serum resistance using P. gingivalis W83 strain through genetic complementation and then recapitulate these studies using P. gingivalis ATCC33277 strain. We further investigate the role of PG0352 and its counterpart (PGN1608) in ATCC33277 in cell growth, biofilm formation, neutrophil killing, cell invasion, and P. gingivalis-induced inflammation. Our results indicate that PG0352 and PGN1608 are implicated in P. gingivalis cell surface structures, hydrophobicity, biofilm formation, resistance to complement and neutrophil killing, and host immune responses. Possible molecular mechanisms involved are also discussed. In summary, this report underscores the importance of sialidases in the pathophysiology of P. gingivalis and opens an avenue to elucidate their underlying molecular mechanisms.
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Affiliation(s)
- Christopher Pham
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Shuaiqi Guo
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Xiao Han
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Laurynn Coleman
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Ching Wooen Sze
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Huizhi Wang
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Chunhao Li
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, USA
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Jiang C, Secundo F, Mao X. Expanding the application range of the κ‑carrageenase OUC-FaKC16A when preparing oligosaccharides from κ-carrageenan and furcellaran. MARINE LIFE SCIENCE & TECHNOLOGY 2023; 5:387-399. [PMID: 37637255 PMCID: PMC10449746 DOI: 10.1007/s42995-023-00181-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 05/10/2023] [Indexed: 08/29/2023]
Abstract
Carrageenan oligosaccharides are important products that have demonstrated numerous bioactivities useful in the food, medicine, and cosmetics industries. However, the specific structure-function relationships of carrageenan oligosaccharides are not clearly described due to the deficiency of high specific carrageenases. Here, a truncated mutant OUC-FaKC16Q based on the reported κ-neocarratetrose (Nκ4)-producing κ-carrageenase OUC-FaKC16A from Flavobacterium algicola was constructed and further studied. After truncating the C-terminal Por_Secre_tail (PorS) domain (responsible for substrate binding), the catalytic efficiency and temperature stability decreased to a certain extent. Surprisingly, this truncation also enabled OUC-FaKC16Q to hydrolyze Nκ4 into κ-neocarrabiose (Nκ2). The offset of Arg265 residue in OUC-FaKC16Q may explain this change. Moreover, the high catalytic abilities, the main products, and the degradation modes of OUC-FaKC16A and OUC-FaKC16Q toward furcellaran were also demonstrated. Data suggested OUC-FaKC16A and OUC-FaKC16Q could hydrolyze furcellaran to produce mainly the desulfated oligosaccharides DA-G-(DA-G4S)2 and DA-G-DA-G4S, respectively. As a result, the spectrum of products of κ-carrageenase OUC-FaKC16A has been fully expanded in this study, indicating its promising potential for application in the biomanufacturing of carrageenan oligosaccharides with specific structures. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-023-00181-2.
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Affiliation(s)
- Chengcheng Jiang
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003 China
- Key Laboratory for Biological Processing of Aquatic Products, China National Light Industry, Qingdao, 266237 China
| | - Francesco Secundo
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”, Consiglio Nazionale delle Ricerche, Via Mario Bianco 9, 20131 Milan, Italy
| | - Xiangzhao Mao
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
- Key Laboratory for Biological Processing of Aquatic Products, China National Light Industry, Qingdao, 266237 China
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4
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Mahmud ASM, Seers CA, Huq NL, Zhang L, Butler CA, Moore C, Cross KJ, Reynolds EC. Production and properties of adhesin-free gingipain proteinase RgpA. Sci Rep 2023; 13:10780. [PMID: 37402780 DOI: 10.1038/s41598-023-37534-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 06/23/2023] [Indexed: 07/06/2023] Open
Abstract
The Arg-specific gingipains of Porphyromonas gingivalis RgpA and RgpB have 97% identical sequences in their catalytic domains yet their propeptides are only 76% identical. RgpA isolates as a proteinase-adhesin complex (HRgpA) which hinders direct kinetic comparison of RgpAcat as a monomer with monomeric RgpB. We tested modifications of rgpA identifying a variant that enabled us to isolate histidine-tagged monomeric RgpA (rRgpAH). Kinetic comparisons between rRgpAH and RgpB used benzoyl-L-Arg-4-nitroanilide with and without cysteine and glycylglycine acceptor molecules. With no glycylglycine, values of Km, Vmax, kcat and kcat/Km for each enzyme were similar, but with glycylglycine Km decreased, Vmax increased and kcat increased ~ twofold for RgpB but ~ sixfold for rRgpAH. The kcat/Km for rRgpAH was unchanged whereas that of RgpB more than halved. Recombinant RgpA propeptide inhibited rRgpAH and RgpB with Ki 13 nM and 15 nM Ki respectively slightly more effectively than RgpB propeptide which inhibited rRgpAH and RgpB with Ki 22 nM and 29 nM respectively (p < 0.0001); a result that may be attributable to the divergent propeptide sequences. Overall, the data for rRgpAH reflected observations previously made by others using HRgpA, indicating rRgpAH fidelity and confirming the first production and isolation of functional affinity tagged RgpA.
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Affiliation(s)
- Abu Sayeed M Mahmud
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Christine A Seers
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - N Laila Huq
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Lianyi Zhang
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Catherine A Butler
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Caroline Moore
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Keith J Cross
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Eric C Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia.
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Sasaki Y, Shoji M, Sueyoshi T, Shibata S, Matsuo T, Yukitake H, Wolf M, Naito M. A conditional gene expression system in Porphyromonas gingivalis for study of the secretion mechanisms of lipoproteins and T9SS cargo proteins. Mol Oral Microbiol 2023. [PMID: 37339018 DOI: 10.1111/omi.12426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 05/16/2023] [Accepted: 06/04/2023] [Indexed: 06/22/2023]
Abstract
The Gram-negative anaerobe, Porphyromonas gingivalis, is known to be a pathogen associated with chronic periodontitis. P. gingivalis possesses virulence factors such as fimbriae and gingipain proteinases. Fimbrial proteins are secreted to the cell surface as lipoproteins. In contrast, gingipain proteinases are secreted into the bacterial cell surface via the type IX secretion system (T9SS). The transport mechanisms of lipoproteins and T9SS cargo proteins are entirely different and remain unknown. Therefore, using the Tet-on system developed for the genus Bacteroides, we newly created a conditional gene expression system in P. gingivalis. We succeeded in establishing conditional expression of nanoluciferase and its derivatives for lipoprotein export, of FimA for a representative of lipoprotein export, and of T9SS cargo proteins such as Hbp35 and PorA for representatives of type 9 protein export. Using this system, we showed that the lipoprotein export signal, which has recently been found in other species in the phylum Bacteroidota, is also functional in FimA, and that a proton motive force inhibitor can affect type 9 protein export. Collectively, our conditional protein expression method is useful for screening inhibitors of virulence factors, and may be used to investigate the role of proteins essential to bacterial survival in vivo.
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Affiliation(s)
- Yuko Sasaki
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Mikio Shoji
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Takayuki Sueyoshi
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Satoshi Shibata
- Molecular Cryo-Electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Faculty of Medicine, Division of Bacteriology, Department of Microbiology & Immunology, Tottori University, Tottori, Japan
| | - Takehiro Matsuo
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Hideharu Yukitake
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Matthias Wolf
- Molecular Cryo-Electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Mariko Naito
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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Maphosa S, Moleleki LN, Motaung TE. Bacterial secretion system functions: evidence of interactions and downstream implications. MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 37083586 DOI: 10.1099/mic.0.001326] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
Unprecedented insights into the biology and functions of bacteria have been and continue to be gained through studying bacterial secretion systems in isolation. This method, however, results in our understanding of the systems being primarily based on the idea that they operate independently, ignoring the subtleties of downstream interconnections. Gram-negative bacteria are naturally able to adapt to and navigate their frequently varied and dynamic surroundings, mostly because of the covert connections between secretion systems. Therefore, to comprehend some of the linked downstream repercussions for organisms that follow this discourse, it is vital to have mechanistic insights into how the intersecretion system functions in bacterial rivalry, virulence, and survival, among other things. To that purpose, this paper discusses a few key instances of molecular antagonistic and interdependent relationships between bacterial secretion systems and their produced functional products.
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Affiliation(s)
- Silindile Maphosa
- Division of Microbiology, Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Hatfield, Pretoria, South Africa
- Department of Plant and Soil Sciences, University of Pretoria, Hatfield, Pretoria, South Africa
- Forestry and Agricultural Biotechnology Institute, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Lucy N Moleleki
- Division of Microbiology, Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Hatfield, Pretoria, South Africa
- Forestry and Agricultural Biotechnology Institute, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Thabiso E Motaung
- Division of Microbiology, Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Hatfield, Pretoria, South Africa
- Forestry and Agricultural Biotechnology Institute, University of Pretoria, Hatfield, Pretoria, South Africa
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Kondo Y, Ohara K, Fujii R, Nakai Y, Sato C, Naito M, Tsukuba T, Kadowaki T, Sato K. Transposon mutagenesis and genome sequencing identify two novel, tandem genes involved in the colony spreading of Flavobacterium collinsii, isolated from an ayu fish, Plecoglossus altivelis. Front Cell Infect Microbiol 2023; 13:1095919. [PMID: 36844397 PMCID: PMC9950754 DOI: 10.3389/fcimb.2023.1095919] [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: 11/11/2022] [Accepted: 01/16/2023] [Indexed: 02/12/2023] Open
Abstract
Bacteria of the family Flavobacteriaceae (flavobacteria) primarily comprise nonpathogenic bacteria that inhabit soil and water (both marine and freshwater). However, some bacterial species in the family, including Flavobacterium psychrophilum and Flavobacterium columnare, are known to be pathogenic to fish. Flavobacteria, including the abovementioned pathogenic bacteria, belong to the phylum Bacteroidota and possess two phylum-specific features, gliding motility and a protein secretion system, which are energized by a common motor complex. Herein, we focused on Flavobacterium collinsii (GiFuPREF103) isolated from a diseased fish (Plecoglossus altivelis). Genomic analysis of F. collinsii GiFuPREF103 revealed the presence of a type IX secretion system and additional genes associated with gliding motility and spreading. Using transposon mutagenesis, we isolated two mutants with altered colony morphology and colony spreading ability; these mutants had transposon insertions in pep25 and lbp26. The glycosylation material profiles revealed that these mutants lacked the high-molecular-weight glycosylated materials present in the wild-type strain. In addition, the wild-type strains exhibited fast cell population movement at the edge of the spreading colony, whereas reduced cell population behavior was observed in the pep25- and lbp26-mutant strains. In the aqueous environment, the surface layers of these mutant strains were more hydrophobic, and they formed biofilms with enhanced microcolony growth compared to those with the wild-type. In Flavobacterium johnsoniae, the Fjoh_0352 and Fjoh_0353 mutant strains were generated, which were based on the ortholog genes of pep25 and lbp26. In these F. johnsoniae mutants, as in F. collinsii GiFuPREF103, colonies with diminished spreading capacity were formed. Furthermore, cell population migration was observed at the edge of the colony in wild-type F. johnsoniae, whereas individual cells, and not cell populations, migrated in these mutant strains. The findings of the present study indicate that pep25 and lbp26 contribute to the colony spreading of F. collinsii.
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Affiliation(s)
- Yoshio Kondo
- Department of Pediatric Dentistry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan,*Correspondence: Yoshio Kondo, ; Keiko Sato,
| | - Kenichi Ohara
- Gifu Prefectural Research Institute for Fisheries and Aquatic Environments, Gifu, Japan
| | - Ryoji Fujii
- Gifu Prefectural Research Institute for Fisheries and Aquatic Environments, Gifu, Japan
| | - Yudai Nakai
- Department of Frontier Oral Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Chikara Sato
- School of Integrative and Global Majors (SIGMA), University of Tsukuba, Ibaraki, Japan,Biological Science Course, Graduate School of Science and Engineering, Aoyama Gakuin University, Kanagawa, Japan,Division of Immune Homeostasis, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan,Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan
| | - Mariko Naito
- Department of Microbiology and Oral Infection, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Takayuki Tsukuba
- Department of Dental Pharmacology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Tomoko Kadowaki
- Department of Frontier Oral Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Keiko Sato
- Department of Frontier Oral Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan,*Correspondence: Yoshio Kondo, ; Keiko Sato,
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Thunes NC, Mohammed HH, Evenhuis JP, Lipscomb RS, Pérez-Pascual D, Stevick RJ, Birkett C, Conrad RA, Ghigo JM, McBride MJ. Secreted peptidases contribute to virulence of fish pathogen Flavobacterium columnare. Front Cell Infect Microbiol 2023; 13:1093393. [PMID: 36816589 PMCID: PMC9936825 DOI: 10.3389/fcimb.2023.1093393] [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: 11/08/2022] [Accepted: 01/18/2023] [Indexed: 02/05/2023] Open
Abstract
Flavobacterium columnare causes columnaris disease in freshwater fish in both natural and aquaculture settings. This disease is often lethal, especially when fish population density is high, and control options such as vaccines are limited. The type IX secretion system (T9SS) is required for F. columnare virulence, but secreted virulence factors have not been fully identified. Many T9SS-secreted proteins are predicted peptidases, and peptidases are common virulence factors of other pathogens. T9SS-deficient mutants, such as ΔgldN and ΔporV, exhibit strong defects in secreted proteolytic activity. The F. columnare genome has many peptidase-encoding genes that may be involved in nutrient acquisition and/or virulence. Mutants lacking individual peptidase-encoding genes, or lacking up to ten peptidase-encoding genes, were constructed and examined for extracellular proteolytic activity, for growth defects, and for virulence in zebrafish and rainbow trout. Most of the mutants retained virulence, but a mutant lacking 10 peptidases, and a mutant lacking the single peptidase TspA exhibited decreased virulence in rainbow trout fry, suggesting that peptidases contribute to F. columnare virulence.
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Affiliation(s)
- Nicole C. Thunes
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Haitham H. Mohammed
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States,Department of Rangeland, Wildlife and Fisheries Management, Texas A&M University, College Station, TX, United States
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, WV, United States
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, WV, United States
| | - David Pérez-Pascual
- Institut Pasteur, Université de Paris-Cité, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Rebecca J. Stevick
- Institut Pasteur, Université de Paris-Cité, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, WV, United States
| | - Rachel A. Conrad
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Jean-Marc Ghigo
- Institut Pasteur, Université de Paris-Cité, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States,*Correspondence: Mark J. McBride,
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Gorasia DG, Veith PD, Reynolds EC. Protein interactome mapping of Porphyromonas gingivalis provides insights into the formation of the PorQ-Z complex of the type IX secretion system. Mol Oral Microbiol 2023; 38:34-40. [PMID: 35862235 PMCID: PMC10947112 DOI: 10.1111/omi.12383] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/14/2022] [Accepted: 07/18/2022] [Indexed: 11/30/2022]
Abstract
Porphyromonas gingivalis is an anaerobic Gram-negative human oral pathogen highly associated with the more severe forms of periodontal disease. Porphyromonas gingivalis utilises the type IX secretion system (T9SS) to transport ∼30 cargo proteins, including multiple virulence factors, to the cell surface. The T9SS is a multiprotein system consisting of at least 20 proteins, and recently, we characterised the protein interactome of these components. Similar to the T9SS, almost all biological processes are mediated through protein-protein interactions (PPIs). Therefore, mapping PPIs is important to understand the biological functions of many proteins in P. gingivalis. Herein, we provide native migration profiles of over 1000 P. gingivalis proteins. Using the T9SS, we demonstrate that our dataset is a useful resource for identifying novel protein interactions. Using this dataset and further analysis of T9SS P. gingivalis mutants, we discover new mechanistic insights into the formation of the PorQ-Z complex of the T9SS. This dataset is a valuable resource for studies of P. gingivalis.
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Affiliation(s)
- Dhana G. Gorasia
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 InstituteThe University of MelbourneParkvilleAustralia
| | - Paul D. Veith
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 InstituteThe University of MelbourneParkvilleAustralia
| | - Eric C. Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 InstituteThe University of MelbourneParkvilleAustralia
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Abstract
This review focuses on nonlytic outer membrane vesicles (OMVs), a subtype of bacterial extracellular vesicles (BEVs) produced by Gram-negative organisms focusing on the mechanisms of their biogenesis, cargo, and function. Throughout, we highlight issues concerning the characterization of OMVs and distinguishing them from other types of BEVs. We also highlight the shortcomings of commonly used methodologies for the study of BEVs that impact the interpretation of their functionality and suggest solutions to standardize protocols for OMV studies.
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Affiliation(s)
| | - Simon R. Carding
- Quadram Institute Bioscience, Norwich, United Kingdom
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
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11
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Dorgan B, Liu Y, Wang S, Aduse-Opoku J, Whittaker SBM, Roberts MAJ, Lorenz CD, Curtis MA, Garnett JA. Structural Model of a Porphyromonas gingivalis type IX Secretion System Shuttle Complex. J Mol Biol 2022; 434:167871. [PMID: 36404438 DOI: 10.1016/j.jmb.2022.167871] [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: 05/28/2022] [Revised: 10/14/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022]
Abstract
Porphyromonas gingivalis is a gram-negative oral anaerobic pathogen and is one of the key causative agents of periodontitis. P. gingivalis utilises a range of virulence factors, including the cysteine protease RgpB, to drive pathogenesis and these are exported and attached to the cell surface via the type IX secretion system (T9SS). All cargo proteins possess a conserved C-terminal signal domain (CTD) which is recognised by the T9SS, and the outer membrane β-barrel protein PorV (PG0027/LptO) can interact with cargo proteins as they are exported to the bacterial surface. Using a combination of solution nuclear magnetic resonance (NMR) spectroscopy, biochemical analyses, machine-learning-based modelling and molecular dynamics (MD) simulations, we present a structural model of a PorV:RgpB-CTD complex from P. gingivalis. This is the first structural insight into CTD recognition by the T9SS and shows how the conserved motifs in the CTD are the primary sites that mediate binding. In PorV, interactions with extracellular surface loops are important for binding the CTD, and together these appear to cradle and lock RgpB-CTD in place. This work provides insight into cargo recognition by PorV but may also have important implications for understanding other aspects of type-IX dependent secretion.
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Affiliation(s)
- Ben Dorgan
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK; School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Yichao Liu
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Sunjun Wang
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Joseph Aduse-Opoku
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Sara B-M Whittaker
- Institute of Cancer & Genomic Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Mark A J Roberts
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London, UK
| | - Christian D Lorenz
- Biological Physics & Soft Matter Research Group, Department of Physics, King's College London, London, UK
| | - Michael A Curtis
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK.
| | - James A Garnett
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK.
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12
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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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13
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Aduse-Opoku J, Joseph S, Devine DA, Marsh PD, Curtis MA. Molecular basis for avirulence of spontaneous variants of Porphyromonas gingivalis: genomic analysis of strains W50, BE1 and BR1. Mol Oral Microbiol 2022; 37:122-132. [PMID: 35622827 PMCID: PMC9328147 DOI: 10.1111/omi.12373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 11/29/2022]
Abstract
The periodontal pathogen Porphyromonas gingivalis is genetically heterogeneous. However, the spontaneous generation of phenotypically different sub‐strains has also been reported. McKee et al. (1988) cultured P. gingivalis W50 in a chemostat during investigations into the growth and properties of this bacterium. Cell viability on blood agar plates revealed two types of non‐pigmenting variants, W50 beige (BE1), and W50 brown (BR1), in samples grown in a high‐hemin medium after day 7, and the population of these variants increased to approximately 25% of the total counts by day 21. W50, BE1 and BR1 had phenotypic alterations in pigmentation, reduced protease activity and haemagglutination and susceptibility to complement killing. Furthermore, the variants exhibited significant attenuation in a mouse model of virulence. Other investigators showed that in BE1, the predominant extracellular Arg‐gingipain was RgpB, and no reaction with an A‐lipopolysaccharide‐specific MAb 1B5 (Collinson et al., 1998; Slaney et al., 2006). In order to determine the genetic basis for these phenotypic properties, we performed hybrid DNA sequence long reads using Oxford Nanopore and the short paired‐end DNA sequence reads of Illumina HiSeq platforms to generate closed circular genomes of the parent and variants. Comparative analysis indicated loss of intact kgp in the 20 kb region of the hagA‐kgp locus in the two variants BE1 and BR1. Deletions in hagA led to smaller open reading frames in the variants, and BR1 had incurred a major chromosomal DNA inversion. Additional minor changes to the genomes of both variants were also observed. Given the importance of Kgp and HagA to protease activity and haemagglutination, respectively, in this bacterium, genomic changes at this locus may account for most of the phenotypic alterations of the variants. The homologous and repetitive nature of hagA and kgp and the features at the inverted junctions are indicative of specific and stable homologous recombination events, which may underlie the genetic heterogeneity of this species.
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Affiliation(s)
- Joseph Aduse-Opoku
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London
| | - Susan Joseph
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London
| | - Deirdre A Devine
- Division of Oral Biology, School of Dentistry, University of Leeds
| | - Philip D Marsh
- Division of Oral Biology, School of Dentistry, University of Leeds
| | - Michael A Curtis
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London
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14
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Type B CTD Proteins Secreted by the Type IX Secretion System Associate with PorP-like Proteins for Cell Surface Anchorage. Int J Mol Sci 2022; 23:ijms23105681. [PMID: 35628493 PMCID: PMC9143113 DOI: 10.3390/ijms23105681] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 02/07/2023] Open
Abstract
The Bacteroidetes type IX secretion system (T9SS) consists of at least 20 components that translocate proteins with type A or type B C-terminal domain (CTD) signals across the outer membrane (OM). While type A CTD proteins are anchored to the cell surface via covalent linkage to the anionic lipopolysaccharide, it is still unclear how type B CTD proteins are anchored to the cell surface. Moreover, very little is known about the PorE and PorP components of the T9SS. In this study, for the first time, we identified a complex comprising the OM β-barrel protein PorP, the OM-associated periplasmic protein PorE and the type B CTD protein PG1035. Cross-linking studies supported direct interactions between PorE-PorP and PorP-PG1035. Furthermore, we show that the formation of the PorE-PorP-PG1035 complex was independent of PorU and PorV. Additionally, the Flavobacterium johnsoniae PorP-like protein, SprF, was found bound to the major gliding motility adhesin, SprB, which is also a type B CTD protein. Together, these results suggest that type B-CTD proteins may anchor to the cell surface by binding to their respective PorP-like proteins.
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15
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Trivedi A, Gosai J, Nakane D, Shrivastava A. Design Principles of the Rotary Type 9 Secretion System. Front Microbiol 2022; 13:845563. [PMID: 35620107 PMCID: PMC9127263 DOI: 10.3389/fmicb.2022.845563] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 01/17/2022] [Indexed: 01/05/2023] Open
Abstract
The Fo ATP synthase, the bacterial flagellar motor, and the bacterial type 9 secretion system (T9SS) are the three known proton motive force driven biological rotary motors. In this review, we summarize the current information on the nuts and bolts of T9SS. Torque generation by T9SS, its role in gliding motility of bacteria, and the mechanism via which a T9SS-driven swarm shapes the microbiota are discussed. The knowledge gaps in our current understanding of the T9SS machinery are outlined.
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Affiliation(s)
- Abhishek Trivedi
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, United States
- Center for Biological Physics, Arizona State University, Tempe, AZ, United States
| | - Jitendrapuri Gosai
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, United States
- Center for Biological Physics, Arizona State University, Tempe, AZ, United States
| | - Daisuke Nakane
- Department of Engineering Science, The University of Electro-Communications, Tokyo, Japan
| | - Abhishek Shrivastava
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, United States
- Center for Biological Physics, Arizona State University, Tempe, AZ, United States
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16
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Vincent MS, Comas Hervada C, Sebban-Kreuzer C, Le Guenno H, Chabalier M, Kosta A, Guerlesquin F, Mignot T, McBride MJ, Cascales E, Doan T. Dynamic proton-dependent motors power type IX secretion and gliding motility in Flavobacterium. PLoS Biol 2022; 20:e3001443. [PMID: 35333857 PMCID: PMC8986121 DOI: 10.1371/journal.pbio.3001443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 04/06/2022] [Accepted: 03/01/2022] [Indexed: 02/06/2023] Open
Abstract
Motile bacteria usually rely on external apparatus like flagella for swimming or pili for twitching. By contrast, gliding bacteria do not rely on obvious surface appendages to move on solid surfaces. Flavobacterium johnsoniae and other bacteria in the Bacteroidetes phylum use adhesins whose movement on the cell surface supports motility. In F. johnsoniae, secretion and helicoidal motion of the main adhesin SprB are intimately linked and depend on the type IX secretion system (T9SS). Both processes necessitate the proton motive force (PMF), which is thought to fuel a molecular motor that comprises the GldL and GldM cytoplasmic membrane proteins. Here, we show that F. johnsoniae gliding motility is powered by the pH gradient component of the PMF. We further delineate the interaction network between the GldLM transmembrane helices (TMHs) and show that conserved glutamate residues in GldL TMH2 are essential for gliding motility, although having distinct roles in SprB secretion and motion. We then demonstrate that the PMF and GldL trigger conformational changes in the GldM periplasmic domain. We finally show that multiple GldLM complexes are distributed in the membrane, suggesting that a network of motors may be present to move SprB along a helical path on the cell surface. Altogether, our results provide evidence that GldL and GldM assemble dynamic membrane channels that use the proton gradient to power both T9SS-dependent secretion of SprB and its motion at the cell surface. Motile bacteria usually rely on external apparatus like flagella or pili, but gliding bacteria do not rely on obvious surface appendages for their movement. This study shows that bacteria in the phylum Bacteroidetes use proton-dependent motors to power protein secretion and gliding motility.
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Affiliation(s)
- Maxence S. Vincent
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Caterina Comas Hervada
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Corinne Sebban-Kreuzer
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Hugo Le Guenno
- Microscopy Core Facility, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université, Marseille, France
| | - Maïalène Chabalier
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Artemis Kosta
- Microscopy Core Facility, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université, Marseille, France
| | - Françoise Guerlesquin
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7283, Marseille, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Eric Cascales
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
- * E-mail: (EC); (TD)
| | - Thierry Doan
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
- * E-mail: (EC); (TD)
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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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18
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Fuchsbauer O, Lunar Silva I, Cascales E, Roussel A, Leone P. Structural and functional analyses of the Porphyromonas gingivalis type IX secretion system PorN protein. J Biol Chem 2022; 298:101618. [PMID: 35065963 PMCID: PMC8861641 DOI: 10.1016/j.jbc.2022.101618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/15/2022] [Accepted: 01/17/2022] [Indexed: 11/13/2022] Open
Abstract
Porphyromonas gingivalis, the major human pathogen bacterium associated with periodontal diseases, secretes virulence factors through the Bacteroidetes-specific type IX secretion system (T9SS). Effector proteins of the T9SS are recognized by the complex via their conserved C-terminal domains (CTDs). Among the 18 proteins essential for T9SS function in P. gingivalis, PorN is a periplasmic protein that forms large ring-shaped structures in association with the PorK outer membrane lipoprotein. PorN also mediates contacts with the PorM subunit of the PorLM energetic module, and with the effector’s CTD. However, no information is available on the PorN structure and on the implication of PorN domains for T9SS assembly and effector recognition. Here we present the crystal structure of PorN at 2.0-Å resolution, which represents a novel fold with no significant similarity to any known structure. In agreement with in silico analyses, we also found that the N- and C-terminal regions of PorN are intrinsically disordered. Our functional studies showed that the N-terminal disordered region is involved in PorN dimerization while the C-terminal disordered region is involved in the interaction with PorK. Finally, we determined that the folded PorN central domain is involved in the interaction with PorM, as well as with the effector’s CTD. Altogether, these results lay the foundations for a more comprehensive model of T9SS architecture and effector transport.
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Affiliation(s)
- Olivier Fuchsbauer
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, Marseille, France; Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, UMR 7257, Marseille, France
| | - Ignacio Lunar Silva
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université - Centre National de la Recherche Scientifique (UMR7255), Marseille Cedex 20, France
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université - Centre National de la Recherche Scientifique (UMR7255), Marseille Cedex 20, France
| | - Alain Roussel
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, Marseille, France; Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, UMR 7257, Marseille, France
| | - Philippe Leone
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, Marseille, France; Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, UMR 7257, Marseille, France.
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19
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Abstract
Porphyromonas gingivalis is an important human pathogen and also a model organism for the Bacteroidetes phylum. O-glycosylation has been reported in this phylum with findings that include the O-glycosylation motif, the structure of the O-glycans in a few species, and an extensive O-glycoproteome analysis in Tannerella forsythia. However, O-glycosylation has not yet been confirmed in P. gingivalis. We therefore used glycoproteomics approaches including partial deglycosylation with trifluoromethanesulfonic acid as well as both HILIC and FAIMS based glycopeptide enrichment strategies leading to the identification of 257 putative glycosylation sites in 145 glycoproteins. The sequence of the major O-glycan was elucidated to be HexNAc-HexNAc(P-Gro-[Ac]0-2)-dHex-Hex-HexA-Hex(dHex). Western blot analyses of mutants lacking the glycosyltransferases PGN_1134 and PGN_1135 demonstrated their involvement in the biosynthesis of the glycan while mass spectrometry analysis of the truncated O-glycans suggested that PGN_1134 and PGN_1135 transfer the two HexNAc sugars. Interestingly, a strong bias against the O-glycosylation of abundant proteins exposed to the cell surface such as abundant T9SS cargo proteins, surface lipoproteins, and outer membrane β-barrel proteins was observed. In contrast, the great majority of proteins associated with the inner membrane or periplasm were glycosylated irrespective of their abundance. The P. gingivalis O-glycosylation system may therefore function to establish the desired physicochemical properties of the periplasm. IMPORTANCEPorphyromonas gingivalis is an oral pathogen primarily associated with severe periodontal disease and further associated with rheumatoid arthritis, dementia, cardiovascular disease, and certain cancers. Protein glycosylation can be important for a variety of reasons including protein function, solubility, protease resistance, and thermodynamic stability. This study has for the first time demonstrated the presence of O-linked glycosylation in this organism by determining the basic structure of the O-glycans and identifying 257 glycosylation sites in 145 proteins. It was found that most proteins exposed to the periplasm were O-glycosylated; however, the abundant surface exposed proteins were not. The O-glycans consisted of seven monosaccharides and a glycerol phosphate with 0–2 acetyl groups. These glycans are likely to have a stabilizing role to the proteins that bear them and must be taken into account when the proteins are produced in heterologous organisms.
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20
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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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21
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Hasegawa Y, Nagano K. Porphyromonas gingivalis FimA and Mfa1 fimbriae: Current insights on localization, function, biogenesis, and genotype. JAPANESE DENTAL SCIENCE REVIEW 2021; 57:190-200. [PMID: 34691295 PMCID: PMC8512630 DOI: 10.1016/j.jdsr.2021.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/16/2021] [Accepted: 09/21/2021] [Indexed: 11/16/2022] Open
Abstract
In general, the periodontal pathogen Porphyromonas gingivalis expresses distinct FimA and Mfa1 fimbriae. Each of these consists of five FimA–E and five Mfa1–5 proteins encoded by the fim and mfa gene clusters, respectively. The main shaft portion comprises FimA and Mfa1, whereas FimB and Mfa2 are localized on the basal portion and function as anchors and elongation terminators. FimC–E and Mfa3–5 participate in the assembly of an accessory protein complex on the tips of each fimbria. Hence, they serve as ligands for the receptors on host cells and other oral bacterial species. The crystal structures of FimA and Mfa1 fimbrial proteins were recently elucidated and new insights into the localization, function, and biogenesis of these proteins have been reported. Several studies indicated a correlation between P. gingivalis pathogenicity and the fimA genotype but not the mfa1 genotype. We recently revealed polymorphisms of all genes in the fim and mfa gene clusters. Intriguingly, mfa5 occurred in numerous different forms and underwent duplication. Detailed structural and functional knowledge of the fimbrial proteins in the context of the entire filament could facilitate the development of innovative therapeutic strategies for structure-based drug design.
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Affiliation(s)
- Yoshiaki Hasegawa
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Keiji Nagano
- Division of Microbiology, Department of Oral Biology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan
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22
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N-glycosylation of a cargo protein C-terminal domain recognized by the type IX secretion system in Cytophaga hutchinsonii affects protein secretion and localization. Appl Environ Microbiol 2021; 88:e0160621. [PMID: 34644163 DOI: 10.1128/aem.01606-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytophaga hutchinsonii is a Gram-negative bacterium belonging to the phylum Bacteroidetes. It digests crystalline cellulose with an unknown mechanism, and possesses a type IX secretion system (T9SS) that can recognize the C-terminal domain (CTD) of the cargo protein as a signal. In this study, the functions of CTD in the secretion and localization of T9SS substrates in C. hutchinsonii were studied by fusing the green fluorescent protein (GFP) with CTD from CHU_2708. CTD is necessary for the secretion of GFP by C. hutchinsonii T9SS. The GFP-CTDCHU_2708 fusion protein was found to be glycosylated in the periplasm with a molecular mass about 5 kDa higher than that predicted from its sequence. The glycosylated protein was sensitive to peptide-N-glycosidase F which can hydrolyze N-linked oligosaccharides. Analyses of mutants obtained by site-directed mutagenesis of asparagine residues in the N-X-S/T motif of CTDCHU_2708 suggest that N-glycosylation occurred on the CTD. CTD N-glycosylation is important for the secretion and localization of GFP-CTD recombinant proteins in C. hutchinsonii. Glycosyltransferase encoding gene chu_3842, a homologous gene of Campylobacter jejuni pglA, was found to participate in the N-glycosylation of C. hutchinsonii. Deletion of chu_3842 affected cell motility, cellulose degradation, and cell resistance to some chemicals. Our study provided the evidence that CTD as the signal of T9SS was N-glycosylated in the periplasm of C. hutchinsonii. IMPORTANCE The bacterial N-glycosylation system has previously only been found in several species of Proteobacteria and Campylobacterota, and the role of N-linked glycans in bacteria is still not fully understood. C. hutchinsonii has a unique cell-contact cellulose degradation mechanism, and many cell surface proteins including cellulases are secreted by the T9SS. Here, we found that C. hutchinsonii, a member of the phylum Bacteroidetes, has an N-glycosylation system. Glycosyltransferase CHU_3842 was found to participate in the N-glycosylation of C. hutchinsonii proteins, and had effects on cell resistance to some chemicals, cell motility, and cellulose degradation. Moreover, N-glycosylation occurs on the CTD translocation signal of T9SS. The glycosylation of CTD apears to play an important role in affecting T9SS substrates transportation and localization. This study enriched our understanding of the widespread existence and multiple biological roles of N-glycosylation in bacteria.
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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; 118:2103573118. [PMID: 34593635 DOI: 10.1073/pnas.2103573118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [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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Okamura H, Hirota K, Yoshida K, Weng Y, He Y, Shiotsu N, Ikegame M, Uchida-Fukuhara Y, Tanai A, Guo J. Outer membrane vesicles of Porphyromonas gingivalis: Novel communication tool and strategy. JAPANESE DENTAL SCIENCE REVIEW 2021; 57:138-146. [PMID: 34484474 PMCID: PMC8399048 DOI: 10.1016/j.jdsr.2021.07.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/09/2021] [Accepted: 07/18/2021] [Indexed: 12/11/2022] Open
Abstract
Extracellular vesicles (EVs) have been recognized as a universal method of cellular communications and are reportedly produced in bacteria, archaea, and eukaryotes. Bacterial EVs are often called “Outer Membrane Vesicles” (OMVs) as they were the result of a controlled blebbing of the outer membrane of gram-negative bacteria such as Porphyromonas gingivalis (P. gingivalis). Bacterial EVs are natural messengers, implicated in intra- and inter-species cell-to-cell communication among microorganism populations present in microbiota. Bacteria can incorporate their pathogens into OMVs; the content of OMVs differs, depending on the type of bacteria. The production of distinct types of OMVs can be mediated by different factors and routes. A recent study highlighted OMVs ability to carry crucial molecules implicated in immune modulation, and, nowadays, they are considered as a way to communicate and transfer messages from the bacteria to the host and vice versa. This review article focuses on the current understanding of OMVs produced from major oral bacteria, P. gingivalis: generation, characteristics, and contents as well as the involvement in signal transduction of host cells and systemic diseases. Our recent study regarding the action of P. gingivalis OMVs in the living body is also summarized.
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Affiliation(s)
- Hirohiko Okamura
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Katsuhiko Hirota
- Department of Medical Hygiene, Dental Hygiene Course, Kochi Gakuen College, Kochi 780-0955, Japan
| | - Kaya Yoshida
- Department of Oral Healthcare Education, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8504, Japan
| | - Yao Weng
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Yuhan He
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Noriko Shiotsu
- Comprehensive Dental Clinic, Okayama University Hospital, Okayama University, Okayama, Japan
| | - Mika Ikegame
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Yoko Uchida-Fukuhara
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Airi Tanai
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Jiajie Guo
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan.,Department of Endodontics, School of Stomatology, China Medical University, Nanjing North Street 117, Shenyang 110002, China
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Tilocca B, Soggiu A, Greco V, Sacchini F, Garofolo G, Paci V, Bonizzi L, Urbani A, Tittarelli M, Roncada P. Comparative proteomics of Brucella melitensis is a useful toolbox for developing prophylactic interventions in a One-Health context. One Health 2021; 13:100253. [PMID: 33997237 PMCID: PMC8100217 DOI: 10.1016/j.onehlt.2021.100253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 11/28/2022] Open
Abstract
Brucellosis caused by Brucella melitensis is a zoonosis frequently reported in the Mediterranean and Middle-East regions and responsible for important economic losses and reduced animal welfare. To date, current strategies applied to control or eradicate the disease relies on diagnostic tests that suffer from limited specificity in non-vaccinated animals; while prophylactic measures, when applied, use a live attenuated bacterial strain characterized by residual virulence on adult pregnant animals and difficulties in distinguishing vaccinated from infected animals. To overcome these issues, studies are desired to elucidate the bacterial biology and the pathogenetic mechanisms of both the vaccinal strain and the pathogenic strains. Proteomics has a potential in tackling issues of One-Health concern; here, we employed label-free shotgun proteomics to investigate the protein repertoire of the vaccinal strain B. melitensis Rev.1 and compare it with the proteome of the Brucella melitensis 16 M, a reference strain representative of B. melitensis field strains. Comparative proteomics profiling underlines common and diverging traits between the two strains. Common features suggest the potential biochemical routes responsible for the residual virulence of the vaccinal strain, whilst the diverging traits are suggestive biochemical signatures to be further investigated to provide an optimized diagnostic capable of discriminating the vaccinated from infected animals. The data presented in this study are openly available in PRIDE data repository at https://www.ebi.ac.uk/pride/, reference number PXD022472.
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Affiliation(s)
- Bruno Tilocca
- Department of Health Sciences, University "Magna Græcia" of Catanzaro, viale Europa, 88100 Catanzaro, Italy
| | - Alessio Soggiu
- Department of Biomedical, Surgical and Dental Sciences- One Health Unit, University of Milano, via Celoria 10, 20133 Milano, Italy
| | - Viviana Greco
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy.,Fondazione Policlinico Universitario Agostino Gemelli, Largo A. Gemelli, 8-00168 Rome, Italy
| | - Flavio Sacchini
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Giuliano Garofolo
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Valentina Paci
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Luigi Bonizzi
- Department of Biomedical, Surgical and Dental Sciences- One Health Unit, University of Milano, via Celoria 10, 20133 Milano, Italy
| | - Andrea Urbani
- Department of Basic Biotechnological Sciences, Intensivological and Perioperative Clinics, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy.,Fondazione Policlinico Universitario Agostino Gemelli, Largo A. Gemelli, 8-00168 Rome, Italy
| | - Manuela Tittarelli
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Centro di Referenza Nazionale per le brucellosi animali, Via Campo Boario 1, 64100 Teramo, Italy
| | - Paola Roncada
- Department of Health Sciences, University "Magna Græcia" of Catanzaro, viale Europa, 88100 Catanzaro, Italy
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Complementation in trans of Porphyromonas gingivalis Lipopolysaccharide Biosynthetic Mutants Demonstrates Lipopolysaccharide Exchange. J Bacteriol 2021; 203:JB.00631-20. [PMID: 33685973 DOI: 10.1128/jb.00631-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/13/2021] [Indexed: 02/07/2023] Open
Abstract
Porphyromonas gingivalis, a bacterial pathogen contributing to human periodontitis, exports and anchors cargo proteins to its surface, enabling the production of black pigmentation using a type IX secretion system (T9SS) and conjugation to anionic lipopolysaccharide (A-LPS). To determine whether T9SS components need to be assembled in situ for correct secretion and A-LPS modification of cargo proteins, combinations of nonpigmented mutants lacking A-LPS or a T9SS component were mixed to investigate in trans complementation. Reacquisition of pigmentation occurred only between an A-LPS mutant and a T9SS mutant, which coincided with A-LPS modification of cargo proteins detected by Western blotting and coimmunoprecipitation/quantitative mass spectrometry. Complementation also occurred using an A-LPS mutant mixed with outer membrane vesicles (OMVs) or purified A-LPS. Fluorescence experiments demonstrated that OMVs can fuse with and transfer lipid to P. gingivalis, leading to the conclusion that complementation of T9SS function occurred through A-LPS transfer between cells. None of the two-strain crosses involving only the five T9SS OM component mutants produced black pigmentation, implying that the OM proteins cannot be transferred in a manner that restores function and surface pigmentation, and hence, a more ordered temporal in situ assembly of T9SS components may be required. Our results show that LPS can be transferred between cells or between cells and OMVs to complement deficiencies in LPS biosynthesis and hemin-related pigmentation to reveal a potentially new mechanism by which the oral microbial community is modulated to produce clinical consequences in the human host.IMPORTANCE Porphyromonas gingivalis is a keystone pathogen contributing to periodontitis in humans, leading to tooth loss. The oral microbiota is essential in this pathogenic process and changes from predominantly Gram-positive (health) to predominantly Gram-negative (disease) species. P. gingivalis uses its type IX secretion system (T9SS) to secrete and conjugate virulence proteins to anionic lipopolysaccharide (A-LPS). This study investigated whether components of this secretion system could be complemented and found that it was possible for A-LPS biosynthetic mutants to be complemented in trans both by strains that had the A-LPS on the cell surface and by exogenous sources of A-LPS. This is the first known example of LPS exchange in a human bacterial pathogen which causes disease through complex microbiota-host interactions.
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PorZ, an Essential Component of the Type IX Secretion System of Porphyromonas gingivalis, Delivers Anionic Lipopolysaccharide to the PorU Sortase for Transpeptidase Processing of T9SS Cargo Proteins. mBio 2021; 12:mBio.02262-20. [PMID: 33622730 PMCID: PMC8545088 DOI: 10.1128/mbio.02262-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cargo proteins of the type IX secretion system (T9SS) in human pathogens from the Bacteroidetes phylum invariably possess a conserved C-terminal domain (CTD) that functions as a signal for outer membrane (OM) translocation. In Porphyromonas gingivalis, the CTD of cargos is cleaved off after translocation, and anionic lipopolysaccharide (A-LPS) is attached. This transpeptidase reaction anchors secreted proteins to the OM. PorZ, a cell surface-associated protein, is an essential component of the T9SS whose function was previously unknown. We recently solved the crystal structure of PorZ and found that it consists of two β-propeller moieties, followed by a CTD. In this study, we performed structure-based modeling, suggesting that PorZ is a carbohydrate-binding protein. Indeed, we found that recombinant PorZ specifically binds A-LPS in vitro Binding was blocked by monoclonal antibodies that specifically react with a phosphorylated branched mannan in the anionic polysaccharide (A-PS) component of A-LPS, but not with the core oligosaccharide or the lipid A endotoxin. Examination of A-LPS derived from a cohort of mutants producing various truncations of A-PS confirmed that the phosphorylated branched mannan is indeed the PorZ ligand. Moreover, purified recombinant PorZ interacted with the PorU sortase in an A-LPS-dependent manner. This interaction on the cell surface is crucial for the function of the "attachment complex" composed of PorU, PorZ, and the integral OM β-barrel proteins PorV and PorQ, which is involved in posttranslational modification and retention of T9SS cargos on the bacterial surface.IMPORTANCE Bacteria have evolved multiple systems to transport effector proteins to their surface or into the surrounding milieu. These proteins have a wide range of functions, including attachment, motility, nutrient acquisition, and toxicity in the host. Porphyromonas gingivalis, the human pathogen responsible for severe gum diseases (periodontitis), uses a recently characterized type IX secretion system (T9SS) to translocate and anchor secreted virulence effectors to the cell surface. Anchorage is facilitated by sortase, an enzyme that covalently attaches T9SS cargo proteins to a unique anionic lipopolysaccharide (A-LPS) moiety of P. gingivalis Here, we show that the T9SS component PorZ interacts with sortase and specifically binds A-LPS. Binding is mediated by a phosphorylated branched mannan repeat in A-LPS polysaccharide. A-LPS-bound PorZ interacts with sortase with significantly higher affinity, facilitating modification of cargo proteins by the cell surface attachment complex of the T9SS.
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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: 39] [Impact Index Per Article: 13.0] [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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Abstract
The type IX secretion system (T9SS) is the most recently discovered secretion system in the gram-negative bacteria and is specific to the Bacteroidetes phylum. It is comprised of at least 19 proteins, which together allows for the secretion and cell surface attachment of a specific group of proteins (T9SS substrates), that harbor a signal sequence at the C-terminus. Here we describe the structural characterization of the PorK, PorN and PorG components of the Porphyromonas gingivalis T9SS using electron microscopy and cross-linking mass spectrometry.
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PorA, a conserved C-terminal domain-containing protein, impacts the PorXY-SigP signaling of the type IX secretion system. Sci Rep 2020; 10:21109. [PMID: 33273542 PMCID: PMC7712824 DOI: 10.1038/s41598-020-77987-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 11/19/2020] [Indexed: 01/07/2023] Open
Abstract
Porphyromonas gingivalis, a periodontal pathogen, translocates many virulence factors including the cysteine proteases referred to as gingipains to the cell surface via the type IX secretion system (T9SS). Expression of the T9SS component proteins is regulated by the tandem signaling of the PorXY two-component system and the ECF sigma factor SigP. However, the details of this regulatory pathway are still unknown. We found that one of the T9SS conserved C-terminal domain-containing proteins, PGN_0123, which we have designated PorA, is involved in regulating expression of genes encoding T9SS structural proteins and that PorA can be translocated onto the cell surface without the T9SS translocation machinery. X-ray crystallography revealed that PorA has a domain similar to the mannose-binding domain of Escherichia coli FimH, the tip protein of Type 1 pilus. Mutations in the cytoplasmic domain of the sensor kinase PorY conferred phenotypic recovery on the ΔporA mutant. The SigP sigma factor, which is activated by the PorXY two-component system, markedly decreased in the ΔporA mutant. These results strongly support a potential role for PorA in relaying a signal from the cell surface to the PorXY-SigP signaling pathway.
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Miller DP, Scott DA. Inherently and Conditionally Essential Protein Catabolism Genes of Porphyromonas gingivalis. Trends Microbiol 2020; 29:54-64. [PMID: 33071035 DOI: 10.1016/j.tim.2020.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 07/01/2020] [Accepted: 09/02/2020] [Indexed: 02/06/2023]
Abstract
Proteases are critical virulence determinants of Porphyromonas gingivalis, an emerging Alzheimer's disease, cancer, and arthritis pathogen and established agent of periodontitis. Transposon sequencing has been employed to define the core essential genome of this bacterium and genes conditionally essential in multiple environments - abscess formation; epithelial colonization; and cigarette smoke toxin exposure; as well as to elucidate genes required for iron acquisition and a functional type 9 secretion system. Validated and predicted protein catabolism genes identified include a combination of established virulence factors and a larger set of seemingly more mundane proteolytic genes. The functions and relevance of genes that share essentiality in multiple disease-relevant conditions are examined. These common stress-related genes may represent particularly attractive therapeutic targets for the control of P. gingivalis infections.
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Affiliation(s)
- Daniel P Miller
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA
| | - David A Scott
- Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, KY, USA.
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Sato K, Okada K, Nakayama K, Imada K. PorM, a core component of bacterial type IX secretion system, forms a dimer with a unique kinked-rod shape. Biochem Biophys Res Commun 2020; 532:114-119. [DOI: 10.1016/j.bbrc.2020.08.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 08/07/2020] [Indexed: 01/06/2023]
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Forrest S, Welch M. Arming the troops: Post-translational modification of extracellular bacterial proteins. Sci Prog 2020; 103:36850420964317. [PMID: 33148128 PMCID: PMC10450907 DOI: 10.1177/0036850420964317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Protein secretion is almost universally employed by bacteria. Some proteins are retained on the cell surface, whereas others are released into the extracellular milieu, often playing a key role in virulence. In this review, we discuss the diverse types and potential functions of post-translational modifications (PTMs) occurring to extracellular bacterial proteins.
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Affiliation(s)
- Suzanne Forrest
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Martin Welch
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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Type IX Secretion System Cargo Proteins Are Glycosylated at the C Terminus with a Novel Linking Sugar of the Wbp/Vim Pathway. mBio 2020; 11:mBio.01497-20. [PMID: 32873758 PMCID: PMC7468200 DOI: 10.1128/mbio.01497-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Porphyromonas gingivalis and Tannerella forsythia, two pathogens associated with severe gum disease, use the type IX secretion system (T9SS) to secrete and attach toxic arrays of virulence factor proteins to their cell surfaces. The proteins are tethered to the outer membrane via glycolipid anchors that have remained unidentified for more than 2 decades. In this study, the first sugar molecules (linking sugars) in these anchors are identified and found to be novel compounds. The novel biosynthetic pathway of these linking sugars is also elucidated. A diverse range of bacteria that do not have the T9SS were found to have the genes for this pathway, suggesting that they may synthesize similar linking sugars for utilization in different systems. Since the cell surface attachment of virulence factors is essential for virulence, these findings reveal new targets for the development of novel therapies. Porphyromonas gingivalis and Tannerella forsythia use the type IX secretion system to secrete cargo proteins to the cell surface where they are anchored via glycolipids. In P. gingivalis, the glycolipid is anionic lipopolysaccharide (A-LPS), of partially known structure. Modified cargo proteins were deglycosylated using trifluoromethanesulfonic acid and digested with trypsin or proteinase K. The residual modifications were then extensively analyzed by tandem mass spectrometry. The C terminus of each cargo protein was amide-bonded to a linking sugar whose structure was deduced to be 2-N-seryl, 3-N-acetylglucuronamide in P. gingivalis and 2-N-glycyl, 3-N-acetylmannuronic acid in T. forsythia. The structures indicated the involvement of the Wbp pathway to produce 2,3-di-N-acetylglucuronic acid and a WbpS amidotransferase to produce the uronamide form of this sugar in P. gingivalis. The wbpS gene was identified as PGN_1234 as its deletion resulted in the inability to produce the uronamide. In addition, the P. gingivalisvimA mutant which lacks A-LPS was successfully complemented by the T. forsythiavimA gene; however, the linking sugar was altered to include glycine rather than serine. After removal of the acetyl group at C-2 by the putative deacetylase, VimE, VimA presumably transfers the amino acid to complete the biosynthesis. The data explain all the enzyme activities required for the biosynthesis of the linking sugar accounting for six A-LPS-specific genes. The linking sugar is therefore the key compound that enables the attachment of cargo proteins in P. gingivalis and T. forsythia. We propose to designate this novel linking sugar biosynthetic pathway the Wbp/Vim pathway.
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Gavriilidou A, Gutleben J, Versluis D, Forgiarini F, van Passel MWJ, Ingham CJ, Smidt H, Sipkema D. Comparative genomic analysis of Flavobacteriaceae: insights into carbohydrate metabolism, gliding motility and secondary metabolite biosynthesis. BMC Genomics 2020; 21:569. [PMID: 32819293 PMCID: PMC7440613 DOI: 10.1186/s12864-020-06971-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 08/05/2020] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Members of the bacterial family Flavobacteriaceae are widely distributed in the marine environment and often found associated with algae, fish, detritus or marine invertebrates. Yet, little is known about the characteristics that drive their ubiquity in diverse ecological niches. Here, we provide an overview of functional traits common to taxonomically diverse members of the family Flavobacteriaceae from different environmental sources, with a focus on the Marine clade. We include seven newly sequenced marine sponge-derived strains that were also tested for gliding motility and antimicrobial activity. RESULTS Comparative genomics revealed that genome similarities appeared to be correlated to 16S rRNA gene- and genome-based phylogeny, while differences were mostly associated with nutrient acquisition, such as carbohydrate metabolism and gliding motility. The high frequency and diversity of genes encoding polymer-degrading enzymes, often arranged in polysaccharide utilization loci (PULs), support the capacity of marine Flavobacteriaceae to utilize diverse carbon sources. Homologs of gliding proteins were widespread among all studied Flavobacteriaceae in contrast to members of other phyla, highlighting the particular presence of this feature within the Bacteroidetes. Notably, not all bacteria predicted to glide formed spreading colonies. Genome mining uncovered a diverse secondary metabolite biosynthesis arsenal of Flavobacteriaceae with high prevalence of gene clusters encoding pathways for the production of antimicrobial, antioxidant and cytotoxic compounds. Antimicrobial activity tests showed, however, that the phenotype differed from the genome-derived predictions for the seven tested strains. CONCLUSIONS Our study elucidates the functional repertoire of marine Flavobacteriaceae and highlights the need to combine genomic and experimental data while using the appropriate stimuli to unlock their uncharted metabolic potential.
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Affiliation(s)
- Asimenia Gavriilidou
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Johanna Gutleben
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Dennis Versluis
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Francesca Forgiarini
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Mark W. J. van Passel
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
- Present address: Ministry of Health, Welfare and Sport, Parnassusplein 5, 2511 VX, The Hague, The Netherlands
| | | | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Detmer Sipkema
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
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The Type IX Secretion System Is Required for Virulence of the Fish Pathogen Flavobacterium psychrophilum. Appl Environ Microbiol 2020; 86:AEM.00799-20. [PMID: 32532872 DOI: 10.1128/aem.00799-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 06/06/2020] [Indexed: 12/15/2022] Open
Abstract
Flavobacterium psychrophilum causes bacterial cold-water disease in wild and aquaculture-reared fish and is a major problem for salmonid aquaculture. The mechanisms responsible for cold-water disease are not known. It was recently demonstrated that the related fish pathogen, Flavobacterium columnare, requires a functional type IX protein secretion system (T9SS) to cause disease. T9SSs secrete cell surface adhesins, gliding motility proteins, peptidases, and other enzymes, any of which may be virulence factors. The F. psychrophilum genome has genes predicted to encode components of a T9SS. Here, we used a SacB-mediated gene deletion technique recently adapted for use in the Bacteroidetes to delete a core F. psychrophilum T9SS gene, gldN The ΔgldN mutant cells were deficient for secretion of many proteins in comparison to wild-type cells. Complementation of the mutant with wild-type gldN on a plasmid restored secretion. Compared to wild-type and complemented strains, the ΔgldN mutant was deficient in adhesion, gliding motility, and extracellular proteolytic and hemolytic activities. The ΔgldN mutant exhibited reduced virulence in rainbow trout and complementation restored virulence, suggesting that the T9SS plays an important role in the disease.IMPORTANCE Bacterial cold-water disease, caused by F. psychrophilum, is a major problem for salmonid aquaculture. Little is known regarding the virulence factors involved in this disease, and control measures are inadequate. A targeted gene deletion method was adapted to F. psychrophilum and used to demonstrate the importance of the T9SS in virulence. Proteins secreted by this system are likely virulence factors and targets for the development of control measures.
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Gorasia DG, Veith PD, Reynolds EC. The Type IX Secretion System: Advances in Structure, Function and Organisation. Microorganisms 2020; 8:microorganisms8081173. [PMID: 32752268 PMCID: PMC7463736 DOI: 10.3390/microorganisms8081173] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/28/2020] [Accepted: 07/28/2020] [Indexed: 12/24/2022] Open
Abstract
The type IX secretion system (T9SS) is specific to the Bacteroidetes phylum. Porphyromonas gingivalis, a keystone pathogen for periodontitis, utilises the T9SS to transport many proteins—including its gingipain virulence factors—across the outer membrane and attach them to the cell surface. Additionally, the T9SS is also required for gliding motility in motile organisms, such as Flavobacterium johnsoniae. At least nineteen proteins have been identified as components of the T9SS, including the three transcription regulators, PorX, PorY and SigP. Although the components are known, the overall organisation and the molecular mechanism of how the T9SS operates is largely unknown. This review focusses on the recent advances made in the structure, function, and organisation of the T9SS machinery to provide further insight into this highly novel secretion system.
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Emrizal R, Nor Muhammad NA. Phylogenetic comparison between Type IX Secretion System (T9SS) protein components suggests evidence of horizontal gene transfer. PeerJ 2020; 8:e9019. [PMID: 32617187 PMCID: PMC7323717 DOI: 10.7717/peerj.9019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 03/28/2020] [Indexed: 12/20/2022] Open
Abstract
Porphyromonas gingivalis is one of the major bacteria that causes periodontitis. Chronic periodontitis is a severe form of periodontal disease that ultimately leads to tooth loss. Virulence factors that contribute to periodontitis are secreted by Type IX Secretion System (T9SS). There are aspects of T9SS protein components that have yet to be characterised. Thus, the aim of this study is to investigate the phylogenetic relationship between members of 20 T9SS component protein families. The Bayesian Inference (BI) trees for 19 T9SS protein components exhibit monophyletic clades for all major classes under Bacteroidetes with strong support for the monophyletic clades or its subclades that is consistent with phylogeny exhibited by the constructed BI tree of 16S rRNA. The BI tree of PorR is different from the 19 BI trees of T9SS protein components as it does not exhibit monophyletic clades for all major classes under Bacteroidetes. There is strong support for the phylogeny exhibited by the BI tree of PorR which deviates from the phylogeny based on 16S rRNA. Hence, it is possible that the porR gene is subjected to horizontal transfer as it is known that virulence factor genes could be horizontally transferred. Seven genes (porR included) that are involved in the biosynthesis of A-LPS are found to be flanked by insertion sequences (IS5 family transposons). Therefore, the intervening DNA segment that contains the porR gene might be transposed and subjected to conjugative transfer. Thus, the seven genes can be co-transferred via horizontal gene transfer. The BI tree of UgdA does not exhibit monophyletic clades for all major classes under Bacteroidetes which is similar to the BI tree of PorR (both are a part of the seven genes). Both BI trees also exhibit similar topology as the four identified clusters with strong support and have similar relative positions to each other in both BI trees. This reinforces the possibility that porR and the other six genes might be horizontally transferred. Other than the BI tree of PorR, the 19 other BI trees of T9SS protein components also exhibit evidence of horizontal gene transfer. However, their genes might undergo horizontal gene transfer less frequently compared to porR because the intervening DNA segment that contains porR is easily exchanged between bacteria under Bacteroidetes due to the presence of insertion sequences (IS5 family transposons) that flank it. In conclusion, this study can provide a better understanding about the phylogeny of T9SS protein components.
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Affiliation(s)
- Reeki Emrizal
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
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39
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Trinh NTT, Tran HQ, Van Dong Q, Cambillau C, Roussel A, Leone P. Crystal structure of Type IX secretion system PorE C-terminal domain from Porphyromonas gingivalis in complex with a peptidoglycan fragment. Sci Rep 2020; 10:7384. [PMID: 32355178 PMCID: PMC7192894 DOI: 10.1038/s41598-020-64115-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 03/31/2020] [Indexed: 02/06/2023] Open
Abstract
Porphyromonas gingivalis, the major human pathogen associated to periodontal diseases, utilizes the Bacteroidetes-specific type IX secretion system (T9SS) to export virulence factors. PorE is a periplasmic multi-domain lipoprotein associated to the outer membrane that was recently identified as essential for T9SS function. Little is known on T9SS at the structural level, and in particular its interaction with peptidoglycan. This prompted us to carry out structural studies on PorE full length as well as on its four isolated domains. Here we report the crystal structure of the C-terminal OmpA_C-like putative peptidoglycan-binding domain at 1.55 Å resolution. An electron density volume was identified in the protein cleft, making it possible to build a naturally-occurring peptidoglycan fragment. This result suggests that PorE interacts with peptidoglycan and that PorE could anchor T9SS to the cell wall.
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Affiliation(s)
- Nhung Thi Trang Trinh
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France.,Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France.,Faculty of Medical Technology, PHENIKAA University, Yen Nghia, Ha Dong, Hanoi 12116, Vietnam.,PHENIKAA Research and Technology Institute (PRATI), A&A Green Phoenix Group JSC, No. 167 Hoang Ngan, Trung Hoa, Cau Giay, Hanoi 11313, Vietnam
| | - Hieu Quang Tran
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France.,Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France
| | - Quyen Van Dong
- Institute of Biotechnology, Vietnam Academy of Science and Technology. 18 Hoang Quoc Viet, Ha Noi, Vietnam.,University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology. 18 Hoang Quoc Viet, Ha Noi, Vietnam
| | - Christian Cambillau
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France.,Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France
| | - Alain Roussel
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France.,Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France
| | - Philippe Leone
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France. .,Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, UMR 7257, 163 Avenue de Luminy, Case 932, 13009, Marseille, France.
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40
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Gorasia DG, Glew MD, Veith PD, Reynolds EC. Quantitative proteomic analysis of the type IX secretion system mutants in Porphyromonas gingivalis. Mol Oral Microbiol 2020; 35:78-84. [PMID: 32040252 DOI: 10.1111/omi.12283] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 12/25/2022]
Abstract
Porphyromonas gingivalis is an anaerobic, gram-negative human oral pathogen highly associated with chronic periodontitis. P. gingivalis utilizes the type IX secretion system (T9SS) to transport many of its virulence factors including the gingipains to the cell surface. The T9SS is comprised of at least 16 proteins and the involvement of these 16 proteins in the T9SS has been verified by creating gene deletion mutants in P. gingivalis. These T9SS mutants are regularly utilized to understand how these proteins function together to allow the secretion of the T9SS substrates. We performed label-free quantitative proteomic analysis on the T9SS protein mutants in P. gingivalis to understand the relative abundance of each T9SS component in different mutants. The T9SS components were reduced in abundance in the porK, porL, porM, porN, sov and porT mutants, whereas they were increased in the porE, porU, porV, porZ and porQ mutants. Sov and PorW appear to be the lowest in abundance and PorV the highest amongst all the T9SS components in P. gingivalis wild-type strain. These results are consistent with the proposed role of Sov as the translocation pore in the outer membrane and PorV as the shuttle protein that transports the T9SS substrates between sub-complexes. Together, the label-free quantitative proteomics analyses showed that different T9SS mutants have vastly different abundances of the T9SS components. This knowledge will greatly assist in interpreting the phenotype of the T9SS mutants as well as selecting the right mutant for exploring the role of an individual component.
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Affiliation(s)
- Dhana G Gorasia
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Michelle D Glew
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Paul D Veith
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Eric C Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
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41
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Larsbrink J, McKee LS. Bacteroidetes bacteria in the soil: Glycan acquisition, enzyme secretion, and gliding motility. ADVANCES IN APPLIED MICROBIOLOGY 2020; 110:63-98. [PMID: 32386606 DOI: 10.1016/bs.aambs.2019.11.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The secretion of extracellular enzymes by soil microbes is rate-limiting in the recycling of biomass. Fungi and bacteria compete and collaborate for nutrients in the soil, with wide ranging ecological impacts. Within soil microbiota, the Bacteroidetes tend to be a dominant phylum, just like in human and animal intestines. The Bacteroidetes thrive because of their ability to secrete diverse arrays of carbohydrate-active enzymes (CAZymes) that target the highly varied glycans in the soil. Bacteroidetes use an energy-saving system of genomic organization, whereby most of their CAZymes are grouped into Polysaccharide Utilization Loci (PULs). These loci enable high level production of specific CAZymes only when their substrate glycans are abundant in the local environment. This gives the Bacteroidetes a clear advantage over other species in the competitive soil environment, further enhanced by the phylum-specific Type IX Secretion System (T9SS). The T9SS is highly effective at secreting CAZymes and/or tethering them to the cell surface, and is tightly coupled to the ability to rapidly glide over solid surfaces, a connection that promotes an active hunt for nutrition. Although the soil Bacteroidetes are less well studied than human gut symbionts, research is uncovering important biochemical and physiological phenomena. In this review, we summarize the state of the art on research into the CAZymes secreted by soil Bacteroidetes in the contexts of microbial soil ecology and the discovery of novel CAZymes for use in industrial biotechnology. We hope that this review will stimulate further investigations into the somewhat neglected enzymology of non-gut Bacteroidetes.
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Affiliation(s)
- Johan Larsbrink
- Wallenberg Wood Science Center, Gothenburg and Stockholm, Sweden; Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Lauren Sara McKee
- Wallenberg Wood Science Center, Gothenburg and Stockholm, Sweden; Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden.
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Benedyk M, Marczyk A, Chruścicka B. Type IX secretion system is pivotal for expression of gingipain-associated virulence of Porphyromonas gingivalis. Mol Oral Microbiol 2019; 34:237-244. [PMID: 31432617 DOI: 10.1111/omi.12268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/13/2019] [Accepted: 08/16/2019] [Indexed: 12/13/2022]
Abstract
Porphyromonas gingivalis, a keystone pathogen in periodontitis, secretes an array of virulence factors including gingipains via the type IX secretion system (T9SS). Inactivation of any component of the T9SS leads to the accumulation of secreted proteins in unprocessed and, in the case of progingipains, inactive forms in the periplasm. To cast light on the paradox that active gingipains are essential for P. gingivalis fitness in vivo but a functional T9SS is not (Frontiers in Cellular and Infection Microbiology, 2017, 7:378), we have compared virulence of wild-type P. gingivalis W83 and the gingipain-null strain with isogenic mutants deficient in individual T9SS components. Using an in vivo subcutaneous chamber mouse model of infection, gingipain-null strain secretion mutants showed no virulence, but their pathogenic potential was reconstituted by coinfection with a low number of the parental strain. Apparently the same mechanism compensated fitness of mutants lacking functional T9SS the transposon library. In contrast to the parental strain, all mutants elicited significantly lower but an effective inflammatory immune response, which cleared infection and prevented systemic dissemination of P. gingivalis to organs. There were no significant differences in immune responses to different secretion mutants, which were generally more stimulatory than the gingipain-null strain. Together, these results indicate that functional T9SS is essential for P. gingivalis virulence apparently through delivery of active gingipains to the bacterial surface. Therefore, T9SS is a legitimate target for drug development to treat periodontitis.
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Affiliation(s)
- Malgorzata Benedyk
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.,Malopolska Center of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Agata Marczyk
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Barbara Chruścicka
- Malopolska Center of Biotechnology, Jagiellonian University, Krakow, Poland
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43
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The Carboxy-Terminal Region of Flavobacterium johnsoniae SprB Facilitates Its Secretion by the Type IX Secretion System and Propulsion by the Gliding Motility Machinery. J Bacteriol 2019; 201:JB.00218-19. [PMID: 31262839 DOI: 10.1128/jb.00218-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 06/26/2019] [Indexed: 12/18/2022] Open
Abstract
Flavobacterium johnsoniae SprB moves rapidly along the cell surface, resulting in gliding motility. SprB secretion requires the type IX secretion system (T9SS). Proteins secreted by the T9SS typically have conserved C-terminal domains (CTDs) belonging to the type A CTD or type B CTD family. Attachment of 70- to 100-amino-acid type A CTDs to a foreign protein allows its secretion. Type B CTDs are common but have received little attention. Secretion of the foreign protein superfolder green fluorescent protein (sfGFP) fused to regions spanning the SprB type B CTD (sfGFP-CTDSprB) was analyzed. CTDs of 218 amino acids or longer resulted in secretion of sfGFP, whereas a 149-amino-acid region did not. Some sfGFP was secreted in soluble form, whereas the rest was attached on the cell surface. Surface-attached sfGFP was rapidly propelled along the cell, suggesting productive interaction with the motility machinery. This did not result in rapid cell movement, which apparently requires additional regions of SprB. Secretion of sfGFP-CTDSprB required coexpression with sprF, which lies downstream of sprB SprF is similar in sequence to Porphyromonas gingivalis PorP. Most F. johnsoniae genes encoding proteins with type B CTDs lie immediately upstream of porP/sprF-like genes. sfGFP was fused to the type B CTD from one such protein (Fjoh_3952). This resulted in secretion of sfGFP only when it was coexpressed with its cognate PorP/SprF-like protein. These results highlight the need for extended regions of type B CTDs and for coexpression with the appropriate PorP/SprF-like protein for efficient secretion and cell surface localization of cargo proteins.IMPORTANCE The F. johnsoniae gliding motility adhesin SprB is delivered to the cell surface by the type IX secretion system (T9SS) and is rapidly propelled along the cell by the motility machinery. How this 6,497-amino-acid protein interacts with the secretion and motility machines is not known. Fusion of the C-terminal 218 amino acids of SprB to a foreign cargo protein resulted in its secretion, attachment to the cell surface, and rapid movement by the motility machinery. Efficient secretion of SprB required coexpression with the outer membrane protein SprF. Secreted proteins that have sequence similarity to SprB in their C-terminal regions are common in the phylum Bacteroidetes and may have roles in adhesion, motility, and virulence.
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44
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Saiki K, Urano-Tashiro Y, Konishi K, Takahashi Y. A screening system using minimal media identifies a flavin-competing inhibitor of Porphyromonas gingivalis growth. FEMS Microbiol Lett 2019; 366:5580286. [PMID: 31578552 DOI: 10.1093/femsle/fnz204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/29/2019] [Indexed: 12/14/2022] Open
Abstract
Chronic periodontitis is caused by dysbiosis of human oral commensals and especially by increase in Porphyromonas gingivalis. Inhibitors of P. gingivalis growth are expected to serve as effective drugs for the periodontal therapy. In the present study, we isolated new growth inhibitors of P. gingivalis using minimal media for P. gingivalis. The minimal media included the previously reported Globulin-Albumin (GA) and the newly developed Lactalbumin-Ferric chloride (LF) and Globulin-Calcium chloride (GC); all supported growth of the wild-type strain of P. gingivalis but did not support the growth of a mutant defective for a type IX secretion system. GC contains CaCl2, indicating that P. gingivalis requires a calcium ion for growth. Using LF and GA, we screened about 100 000 compounds and identified 73 that strongly inhibited the growth of P. gingivalis. More than half of these candidates would not have been obtained if these minimal media had not been used in our screen. One of our candidate inhibitors was diphenyleneiodonium chloride (DPIC), which showed strong bactericidal activity against P. gingivalis. Excess amounts of flavin adenine dinucleotide or flavin mononucleotide suppressed the inhibitory activity of DPIC, suggesting that DPIC would be a novel potent growth inhibitor.
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Affiliation(s)
- Keitarou Saiki
- Department of Microbiology, Nippon Dental University School of Life Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159, Japan
| | - Yumiko Urano-Tashiro
- Department of Microbiology, Nippon Dental University School of Life Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159, Japan
| | - Kiyoshi Konishi
- Department of Microbiology, Nippon Dental University School of Life Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159, Japan
| | - Yukihiro Takahashi
- Department of Microbiology, Nippon Dental University School of Life Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159, Japan
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45
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Veillard F, Sztukowska M, Nowakowska Z, Mizgalska D, Thøgersen IB, Enghild JJ, Bogyo M, Potempa B, Nguyen KA, Potempa J. Proteolytic processing and activation of gingipain zymogens secreted by T9SS of Porphyromonas gingivalis. Biochimie 2019; 166:161-172. [PMID: 31212040 DOI: 10.1016/j.biochi.2019.06.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/13/2019] [Indexed: 10/26/2022]
Abstract
Porphyromonas gingivalis uses a type IX secretion system (T9SS) to deliver more than 30 proteins to the bacterial surface using a conserved C-terminal domain (CTD) as an outer membrane translocation signal. On the surface, the CTD is cleaved and an anionic lipopolysaccharide (A-PLS) is attached by PorU sortase. Among T9SS cargo proteins are cysteine proteases, gingipains, which are secreted as inactive zymogens requiring removal of an inhibiting N-terminal prodomain (PD) for activation. Here, we have shown that the gingipain proRgpB isolated from the periplasm of a T9SS-deficient P. gingivalis strain was stable and did not undergo autocatalytic activation. Addition of purified, active RgpA or RgpB, but not Lys-specific Kgp, efficiently cleaved the PD of proRgpB but catalytic activity remained inhibited because of inhibition of the catalytic domain in trans by the PD. In contrast, active RgpB was generated from the zymogen, although at a slow rate, by gingipain-null P. gingivalis lysate or intact bacterial cell suspension. This activation was dependent on the presence of the PorU sortase. Interestingly, maturation of proRgpB with the catalytic cysteine residues mutated to Ala expressed in the ΔRgpA mutant strain was indistinguishable from that in the parental strain. Cumulatively, this suggests that PorU not only has sortase activity but is also engaged in activation of gingipain zymogens on the bacterial cell surface.
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Affiliation(s)
- Florian Veillard
- Université de Strasbourg, CNRS, Insect Models of Innate Immunity (M3I; UPR9022), 67084, Strasbourg, France; Department of Oral Immunity and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA.
| | - Maryta Sztukowska
- Department of Oral Immunity and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA; University of Information Technology and Management, Rzeszow, Poland
| | - Zuzanna Nowakowska
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland; Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Danuta Mizgalska
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Ida B Thøgersen
- Interdisciplinary Nanoscience Center (iNANO), and the Department of Molecular Biology and Genetics, Aarhus University, Aarhus, DK-8000, Denmark
| | - Jan J Enghild
- Interdisciplinary Nanoscience Center (iNANO), and the Department of Molecular Biology and Genetics, Aarhus University, Aarhus, DK-8000, Denmark
| | - Matthew Bogyo
- Department of Pathology and Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Barbara Potempa
- Department of Oral Immunity and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA
| | - Ky-Anh Nguyen
- Discipline of Life Sciences, School of Dentistry, University of Sydney, Sydney, NSW, 2006, Australia; Institute of Dental Research, Westmead Centre for Oral Health, Sydney, NSW, 2145, Australia
| | - Jan Potempa
- Department of Oral Immunity and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, USA; Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
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Hu D, Guo Y, Guo J, Wang Y, Pan Z, Xiao Y, Wang X, Hu S, Liu M, Li Z, Bi D, Zhou Z. Deletion of the Riemerella anatipestifer type IX secretion system gene sprA results in differential expression of outer membrane proteins and virulence. Avian Pathol 2019; 48:191-203. [PMID: 30640518 DOI: 10.1080/03079457.2019.1566594] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Riemerella anatipestifer (RA), the causative agent of infectious serositis that targets ducklings and other poultry, secretes protein via the type IX secretion system (T9SS). The proteins transported by T9SS are located on the bacterial cell surface or secreted into the extracellular milieu. In this study, a sprA deletion mutant was constructed encoding a core protein of T9SS to investigate its influence on outer membrane protein expression and its role in virulence. Compared with the wild-type RA-YM strain, the deletion mutant ΔsprA failed to digest gelatin, showed the same growth rate in the logarithmic phase and exhibited greater sensitivity to the bactericidal activity of duck sera, whereas the complemented strain restored these phenotypes. The outer membrane proteome of RA-YM and the ΔsprA mutant were analyzed by Tandem Mass Tags, which revealed 198 proteins with predicted localization to the cell envelope. Sixty-three of these proteins were differentially expressed in the outer membrane, with 43 up-regulated and 20 down-regulated. Among the twelve outer membrane proteins which were secreted by T9SS, four proteins were up-regulated and one protein was down-regulated. Animal experiments demonstrated that the median lethal dose of the mutant strain ΔsprA was about 500 times higher than that of the wild-type RA-YM strain, and bacterial loads in blood, brain, heart, liver and spleen of the ΔsprA-infected ducks were significantly reduced. Our results indicate that the SprA is a virulence-associated factor of RA, and its absence results in altered abundance of outer membrane proteins, and secretion disorders associated with some of the T9SS effector proteins.
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Affiliation(s)
- Di Hu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Yunqing Guo
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Jie Guo
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Ying Wang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Zhe Pan
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Yuncai Xiao
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Xiliang Wang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Sishun Hu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Mei Liu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Zili Li
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Dingren Bi
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
| | - Zutao Zhou
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , People's Republic of China
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Abstract
ABSTRACT
Members of the phylum
Bacteroidetes
have many unique features, including gliding motility and the type IX protein secretion system (T9SS).
Bacteroidetes
gliding and T9SSs are common in, but apparently confined to, this phylum. Most, but not all, members of the phylum secrete proteins using the T9SS, and most also exhibit gliding motility. T9SSs secrete cell surface components of the gliding motility machinery and also secrete many extracellular or cell surface enzymes, adhesins, and virulence factors. The components of the T9SS are novel and are unrelated to those of other bacterial secretion systems. Proteins secreted by the T9SS rely on the Sec system to cross the cytoplasmic membrane, and they use the T9SS for delivery across the outer membrane. Secreted proteins typically have conserved C-terminal domains that target them to the T9SS. Some of the T9SS components were initially identified as proteins required for gliding motility. Gliding does not involve flagella or pili and instead relies on the rapid movement of motility adhesins, such as SprB, along the cell surface by the gliding motor. Contact of the adhesins with the substratum provides the traction that results in cell movement. SprB and other motility adhesins are delivered to the cell surface by the T9SS. Gliding and the T9SS appear to be intertwined, and components of the T9SS that span the cytoplasmic membrane may energize both gliding and protein secretion. The functions of the individual proteins in each process are the subject of ongoing investigations.
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Role of Acetyltransferase PG1842 in Gingipain Biogenesis in Porphyromonas gingivalis. J Bacteriol 2018; 200:JB.00385-18. [PMID: 30249709 DOI: 10.1128/jb.00385-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/20/2018] [Indexed: 02/02/2023] Open
Abstract
Porphyromonas gingivalis, the major etiologic agent in adult periodontitis, produces large amounts of proteases that are important for its survival and pathogenesis. The activation/maturation of gingipains, the major proteases, in P. gingivalis involves a complex network of processes which are not yet fully understood. VimA, a putative acetyltransferase and virulence-modulating protein in P. gingivalis, is known to be involved in gingipain biogenesis. P. gingivalis FLL92, a vimA-defective isogenic mutant (vimA::ermF-ermAM) showed late-onset gingipain activity at stationary phase, indicating the likelihood of a complementary functional VimA homolog in that growth phase. This study aimed to identify a functional homolog(s) that may activate the gingipains in the absence of VimA at stationary phase. A bioinformatics analysis showed five putative GCN5-related N-acetyltransferases (GNAT) encoded in the P. gingivalis genome that are structurally related to VimA. Allelic exchange mutagenesis was used to make deletion mutants for these acetyltransferases in the P. gingivalis vimA-defective mutant FLL102 (ΔvimA::ermF) genetic background. One of the mutants, designated P. gingivalis FLL126 (ΔvimA-ΔPG1842), did not show any late-onset gingipain activity at stationary phase compared to that of the parent strain P. gingivalis FLL102. A Western blot analysis of stationary-phase extracellular fractions with antigingipain antibodies showed immunoreactive bands that were similar in size to those for the progingipain species present only in the ΔvimA-ΔPG1842 isogenic mutant. Both recombinant VimA and PG1842 proteins acetylated Y230, K247, and K248 residues in the pro-RgpB substrate. Collectively, these findings indicate that PG1842 may play a significant role in the activation/maturation of gingipains in P. gingivalis IMPORTANCE Gingipain proteases are key virulence factors secreted by Porphyromonas gingivalis that cause periodontal tissue damage and the degradation of the host immune system proteins. Gingipains are translated as an inactive zymogen to restrict intracellular proteolytic activity before secretion. Posttranslational processing converts the inactive proenzyme to a catalytically active protease. Gingipain biogenesis, including its secretion and activation, is a complex process which is still not fully understood. One recent study identified acetylated lysine residues in the three gingipains RgpA, RgpB, and Kgp, thus indicating a role for acetylation in gingipain biogenesis. Here, we show that the acetyltransferases VimA and PG1842 can acetylate the pro-RgpB gingipain species. These findings further indicate that acetylation is a potential mechanism in the gingipain activation/maturation pathway in P. gingivalis.
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Type 9 secretion system structures reveal a new protein transport mechanism. Nature 2018; 564:77-82. [PMID: 30405243 DOI: 10.1038/s41586-018-0693-y] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 09/13/2018] [Indexed: 12/24/2022]
Abstract
The type 9 secretion system (T9SS) is the protein export pathway of bacteria of the Gram-negative Fibrobacteres-Chlorobi-Bacteroidetes superphylum and is an essential determinant of pathogenicity in severe periodontal disease. The central element of the T9SS is a so-far uncharacterized protein-conducting translocon located in the bacterial outer membrane. Here, using cryo-electron microscopy, we provide structural evidence that the translocon is the T9SS protein SprA. SprA forms an extremely large (36-strand) single polypeptide transmembrane β-barrel. The barrel pore is capped on the extracellular end, but has a lateral opening to the external membrane surface. Structures of SprA bound to different components of the T9SS show that partner proteins control access to the lateral opening and to the periplasmic end of the pore. Our results identify a protein transporter with a distinctive architecture that uses an alternating access mechanism in which the two ends of the protein-conducting channel are open at different times.
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Sato K, Kakuda S, Yukitake H, Kondo Y, Shoji M, Takebe K, Narita Y, Naito M, Nakane D, Abiko Y, Hiratsuka K, Suzuki M, Nakayama K. Immunoglobulin‐like domains of the cargo proteins are essential for protein stability during secretion by the type IX secretion system. Mol Microbiol 2018; 110:64-81. [DOI: 10.1111/mmi.14083] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2018] [Indexed: 01/12/2023]
Affiliation(s)
- Keiko Sato
- Department of Microbiology and Oral Infection Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
| | - Shinji Kakuda
- Institute for Protein Research Osaka University Yamadaoka, Suita Osaka 565‐0871Japan
| | - Hideharu Yukitake
- Department of Microbiology and Oral Infection Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
| | - Yoshio Kondo
- Department of Pediatric Dentistry Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
| | - Mikio Shoji
- Department of Microbiology and Oral Infection Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
| | - Katsuki Takebe
- Institute for Protein Research Osaka University Yamadaoka, Suita Osaka 565‐0871Japan
| | - Yuka Narita
- Department of Functional Bioscience, Infection Biology Fukuoka Dental College Matsudo, Tamura, Sawara, Fukuoka 814‐0913Japan
| | - Mariko Naito
- Department of Microbiology and Oral Infection Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
| | - Daisuke Nakane
- Department of Physics, Faculty of Science Gakushuin University Toshima‐ku, Tokyo 171‐8588Japan
| | - Yoshimitsu Abiko
- Department of Biochemistry and Molecular Biology Nihon University School of Dentistry at Matsudo Matsudo Chiba 271‐8587Japan
| | - Koichi Hiratsuka
- Department of Biochemistry and Molecular Biology Nihon University School of Dentistry at Matsudo Matsudo Chiba 271‐8587Japan
| | - Mamoru Suzuki
- Institute for Protein Research Osaka University Yamadaoka, Suita Osaka 565‐0871Japan
| | - Koji Nakayama
- Department of Microbiology and Oral Infection Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
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