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Thunes NC, Evenhuis JP, Lipscomb RS, Pérez-Pascual D, Stevick RJ, Birkett C, Ghigo JM, McBride MJ. Gliding motility proteins GldJ and SprB contribute to Flavobacterium columnare virulence. J Bacteriol 2024; 206:e0006824. [PMID: 38517170 PMCID: PMC11025331 DOI: 10.1128/jb.00068-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/23/2024] Open
Abstract
Flavobacterium columnare causes columnaris disease in fish. Columnaris disease is incompletely understood, and adequate control measures are lacking. The type IX secretion system (T9SS) is required for F. columnare gliding motility and virulence. The T9SS and gliding motility machineries share some, but not all, components. GldN (required for gliding and for secretion) and PorV (involved in secretion but not required for gliding) are both needed for virulence, implicating T9SS-mediated secretion in virulence. The role of motility in virulence is uncertain. We constructed and analyzed sprB, sprF, and gldJ mutants that were defective for motility but that maintained T9SS function to understand the role of motility in virulence. Wild-type cells moved rapidly and formed spreading colonies. In contrast, sprB and sprF deletion mutants were partially defective in gliding and formed nonspreading colonies. Both mutants exhibited reduced virulence in rainbow trout fry. A gldJ deletion mutant was nonmotile, secretion deficient, and avirulent in rainbow trout fry. To separate the roles of GldJ in secretion and in motility, we generated gldJ truncation mutants that produce nearly full-length GldJ. Mutant gldJ563, which produces GldJ truncated at amino acid 563, was defective for gliding but was competent for secretion as measured by extracellular proteolytic activity. This mutant displayed reduced virulence in rainbow trout fry, suggesting that motility contributes to virulence. Fish that survived exposure to the sprB deletion mutant or the gldJ563 mutant exhibited partial resistance to later challenge with wild-type cells. The results aid our understanding of columnaris disease and may suggest control strategies.IMPORTANCEFlavobacterium columnare causes columnaris disease in many species of freshwater fish in the wild and in aquaculture systems. Fish mortalities resulting from columnaris disease are a major problem for aquaculture. F. columnare virulence is incompletely understood, and control measures are inadequate. Gliding motility and protein secretion have been suggested to contribute to columnaris disease, but evidence directly linking motility to disease was lacking. We isolated and analyzed mutants that were competent for secretion but defective for motility. Some of these mutants exhibited decreased virulence. Fish that had been exposed to these mutants were partially protected from later exposure to the wild type. The results contribute to our understanding of columnaris disease and may aid development of control strategies.
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Affiliation(s)
- Nicole C. Thunes
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - David Pérez-Pascual
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Rebecca J. Stevick
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - Jean-Marc Ghigo
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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2
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Carsten A, Wolters M, Aepfelbacher M. Super-resolution fluorescence microscopy for investigating bacterial cell biology. Mol Microbiol 2024; 121:646-658. [PMID: 38041391 DOI: 10.1111/mmi.15203] [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: 08/04/2023] [Revised: 11/13/2023] [Accepted: 11/16/2023] [Indexed: 12/03/2023]
Abstract
Super-resolution fluorescence microscopy technologies developed over the past two decades have pushed the resolution limit for fluorescently labeled molecules into the nanometer range. These technologies have the potential to study bacterial structures, for example, macromolecular assemblies such as secretion systems, with single-molecule resolution on a millisecond time scale. Here we review recent applications of super-resolution fluorescence microscopy with a focus on bacterial secretion systems. We also describe MINFLUX fluorescence nanoscopy, a relatively new technique that promises to one day produce molecular movies of molecular machines in action.
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Affiliation(s)
- Alexander Carsten
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Manuel Wolters
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Martin Aepfelbacher
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg Eppendorf, Hamburg, Germany
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3
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Lauber F, Deme JC, Liu X, Kjær A, Miller HL, Alcock F, Lea SM, Berks BC. Structural insights into the mechanism of protein transport by the Type 9 Secretion System translocon. Nat Microbiol 2024; 9:1089-1102. [PMID: 38538833 PMCID: PMC10994853 DOI: 10.1038/s41564-024-01644-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 02/19/2024] [Indexed: 04/06/2024]
Abstract
Secretion systems are protein export machines that enable bacteria to exploit their environment through the release of protein effectors. The Type 9 Secretion System (T9SS) is responsible for protein export across the outer membrane (OM) of bacteria of the phylum Bacteroidota. Here we trap the T9SS of Flavobacterium johnsoniae in the process of substrate transport by disrupting the T9SS motor complex. Cryo-EM analysis of purified substrate-bound T9SS translocons reveals an extended translocon structure in which the previously described translocon core is augmented by a periplasmic structure incorporating the proteins SprE, PorD and a homologue of the canonical periplasmic chaperone Skp. Substrate proteins bind to the extracellular loops of a carrier protein within the translocon pore. As transport intermediates accumulate on the translocon when energetic input is removed, we deduce that release of the substrate-carrier protein complex from the translocon is the energy-requiring step in T9SS transport.
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Affiliation(s)
- Frédéric Lauber
- Department of Biochemistry, University of Oxford, Oxford, UK
- de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Justin C Deme
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- The Central Oxford Structural Molecular Imaging Centre (COSMIC), University of Oxford, Oxford, UK
| | - Xiaolong Liu
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Andreas Kjær
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Helen L Miller
- Biological Physics Research Group, Department of Physics, University of Oxford, Oxford, UK
| | - Felicity Alcock
- Department of Biochemistry, University of Oxford, Oxford, UK
- Newcastle University Biosciences Institute, Newcastle University, Newcastle, UK
| | - Susan M Lea
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA.
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
- The Central Oxford Structural Molecular Imaging Centre (COSMIC), University of Oxford, Oxford, UK.
| | - Ben C Berks
- Department of Biochemistry, University of Oxford, Oxford, UK.
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4
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Zammit M, Bartoli J, Kellenberger C, Melani P, Roussel A, Cascales E, Leone P. Structure-function analysis of PorX Fj, the PorX homolog from Flavobacterium johnsioniae, suggests a role of the CheY-like domain in type IX secretion motor activity. Sci Rep 2024; 14:6577. [PMID: 38503809 PMCID: PMC10951265 DOI: 10.1038/s41598-024-57089-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 03/14/2024] [Indexed: 03/21/2024] Open
Abstract
The type IX secretion system (T9SS) is a large multi-protein transenvelope complex distributed into the Bacteroidetes phylum and responsible for the secretion of proteins involved in pathogenesis, carbohydrate utilization or gliding motility. In Porphyromonas gingivalis, the two-component system PorY sensor and response regulator PorX participate to T9SS gene regulation. Here, we present the crystal structure of PorXFj, the Flavobacterium johnsoniae PorX homolog. As for PorX, the PorXFj structure is comprised of a CheY-like N-terminal domain and an alkaline phosphatase-like C-terminal domain separated by a three-helix bundle central domain. While not activated and monomeric in solution, PorXFj crystallized as a dimer identical to active PorX. The CheY-like domain of PorXFj is in an active-like conformation, and PorXFj possesses phosphodiesterase activity, in agreement with the observation that the active site of its phosphatase-like domain is highly conserved with PorX.
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Affiliation(s)
- Mariotte Zammit
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR7255), Institut de Microbiologie de la Méditerranée, Aix Marseille Univ, Centre National de la Recherche Scientifique, Marseille, France
| | - Julia Bartoli
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR7255), Institut de Microbiologie de la Méditerranée, Aix Marseille Univ, Centre National de la Recherche Scientifique, Marseille, France
| | - Christine Kellenberger
- Laboratoire de Chimie Bactérienne (LCB, UMR7283), Institut de Microbiologie de la Méditerranée, Aix Marseille Univ, Centre National de la Recherche Scientifique, Marseille, France
| | - Pauline Melani
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR7255), Institut de Microbiologie de la Méditerranée, Aix Marseille Univ, Centre National de la Recherche Scientifique, Marseille, France
| | - Alain Roussel
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR7255), Institut de Microbiologie de la Méditerranée, Aix Marseille Univ, Centre National de la Recherche Scientifique, Marseille, France
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR7255), Institut de Microbiologie de la Méditerranée, Aix Marseille Univ, Centre National de la Recherche Scientifique, Marseille, France
| | - Philippe Leone
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM, UMR7255), Institut de Microbiologie de la Méditerranée, Aix Marseille Univ, Centre National de la Recherche Scientifique, Marseille, France.
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5
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Zoued A, Duneau JP, Cascales E. Bacterial One- and Two-Hybrid Assays to Monitor Transmembrane Helix Interactions. Methods Mol Biol 2024; 2715:259-271. [PMID: 37930534 DOI: 10.1007/978-1-0716-3445-5_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
In transenvelope multiprotein machines such as bacterial secretion systems, protein-protein interactions not only occur between soluble domains but might also be mediated by helix-helix contacts in the inner membrane. Several assays have been therefore developed to test homotypic and heterotypic interactions between transmembrane α-helices in their native membrane environment. Here, we provide detailed protocols for two genetic assays, TOXCAT and GALLEX, which are based on the reconstitution of dimeric regulators allowing the control of expression of reporter genes.
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Affiliation(s)
- Abdelrahim Zoued
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ, CNRS, Marseille, France
- Centre International de Recherche en Infectiologie, UMR5308, Université Claude Bernard Lyon 1 - INSERM - CNRS, Lyon, France
| | - Jean-Pierre Duneau
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ, CNRS, Marseille, France
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ, CNRS, Marseille, France.
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6
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Chabalier M, Doan T, Cascales E. Probing Protein Topology and Conformation by Limited Proteolysis. Methods Mol Biol 2024; 2715:111-119. [PMID: 37930525 DOI: 10.1007/978-1-0716-3445-5_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Proteases are enzymes that catalyze the hydrolytic degradation of other proteins into peptides or amino acids through the digestion of the peptide bond. Promiscuous proteases that target a wide range of proteins are distinguished from specific proteases that have a narrow range of substrates. In terms of activity, endoproteases cleave their substrates at specific residues within the target proteins, whereas exoproteases cleave from one extremity and may have processive activities. Proteases are therefore very useful tools to study proteins, notably their structure or conformation. In addition, proteases can be used to probe the topology of bacterial membrane proteins. Here, we describe limited protease accessibility assays to define inner membrane protein topology and conformational changes based on digestion profiles.
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Affiliation(s)
- Maïalène Chabalier
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ - CNRS, Marseille, France
| | - Thierry Doan
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ - CNRS, Marseille, France
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ - CNRS, Marseille, France.
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7
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Pauli TM, Julius A, Costa F, Eschrig S, Moosmüller J, Fischer L, Schanzenbach C, Schmidt FC, Ortner M, Langosch D. Interaction of Substrates with γ-Secretase at the Level of Individual Transmembrane Helices-A Methodological Approach. Int J Mol Sci 2023; 24:14396. [PMID: 37762696 PMCID: PMC10531681 DOI: 10.3390/ijms241814396] [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: 07/27/2023] [Revised: 08/23/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023] Open
Abstract
Intramembrane proteases, such as γ secretase, typically recruit multiple substrates from an excess of single-span membrane proteins. It is currently unclear to which extent substrate recognition depends on specific interactions of their transmembrane domains (TMDs) with TMDs of a protease. Here, we investigated a large number of potential pairwise interactions between TMDs of γ secretase and a diverse set of its substrates using two different configurations of BLaTM, a genetic reporter system. Our results reveal significant interactions between TMD2 of presenilin, the enzymatic subunit of γ secretase, and the TMD of the amyloid precursor protein, as well as of several other substrates. Presenilin TMD2 is a prime candidate for substrate recruitment, as has been shown from previous studies. In addition, the amyloid precursor protein TMD enters interactions with presenilin TMD 4 as well as with the TMD of nicastrin. Interestingly, the Gly-rich interfaces between the amyloid precursor protein TMD and presenilin TMDs 2 and 4 are highly similar to its homodimerization interface. In terms of methodology, the economics of the newly developed library-based method could prove to be a useful feature in related future work for identifying heterotypic TMD-TMD interactions within other biological contexts.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Martin Ortner
- Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany; (T.M.P.); (A.J.); (F.C.); (S.E.); (J.M.); (L.F.); (C.S.); (F.C.S.)
| | - Dieter Langosch
- Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany; (T.M.P.); (A.J.); (F.C.); (S.E.); (J.M.); (L.F.); (C.S.); (F.C.S.)
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8
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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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9
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Live Cell Imaging of Gliding Motility of Flavobacterium johnsoniae Under High-Resolution Microscopy. Methods Mol Biol 2023; 2646:277-286. [PMID: 36842122 DOI: 10.1007/978-1-0716-3060-0_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Many phylum Bacteroidetes bacteria are motile without either flagella or pili. These cells move on surfaces such as glass or agar, and a motor generates a propulsion force for the cells via a proton motive force across the cytoplasmic membrane. The gliding motility depends on the helical track of cell adhesin along the longer axis of the cell body. Here, we describe live-cell imaging of gliding motility under optical microscopy, as well as an immunofluorescent labeling method for visualizing helical trajectories.
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10
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Shibata S, Tahara YO, Katayama E, Kawamoto A, Kato T, Zhu Y, Nakane D, Namba K, Miyata M, McBride MJ, Nakayama K. Filamentous structures in the cell envelope are associated with bacteroidetes gliding machinery. Commun Biol 2023; 6:94. [PMID: 36690840 PMCID: PMC9870892 DOI: 10.1038/s42003-023-04472-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/12/2023] [Indexed: 01/24/2023] Open
Abstract
Many bacteria belonging to the phylum Bacteroidetes move on solid surfaces, called gliding motility. In our previous study with the Bacteroidetes gliding bacterium Flavobacterium johnsoniae, we proposed a helical loop track model, where adhesive SprB filaments are propelled along a helical loop on the cell surface. In this study, we observed the gliding cell rotating counterclockwise about its axis when viewed from the rear to the advancing direction of the cell and revealed that one labeled SprB focus sometimes overtook and passed another SprB focus that was moving in the same direction. Several electron microscopic analyses revealed the presence of a possible multi-rail structure underneath the outer membrane, which was associated with SprB filaments and contained GldJ protein. These results provide insights into the mechanism of Bacteroidetes gliding motility, in which the SprB filaments are propelled along tracks that may form a multi-rail system underneath the outer membrane. The insights may give clues as to how the SprB filaments get their driving force.
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Affiliation(s)
- Satoshi Shibata
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
- Division of Bacteriology, Department of Microbiology and Immunology, Faculty of Medicine, Tottori University, Yonago, Tottori, Japan.
| | - Yuhei O Tahara
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka Metropolitan University, Sumiyoshi-ku, Osaka, Japan
- Graduate School of Science, Osaka Metropolitan University, Sumiyoshi-ku, Osaka, Japan
| | - Eisaku Katayama
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka Metropolitan University, Sumiyoshi-ku, Osaka, Japan
- Waseda Research Institute for Science and Engineering, Okubo Shinjyuku, Tokyo, Japan
| | - Akihiro Kawamoto
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Takayuki Kato
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Yongtao Zhu
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201, USA
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, China
| | - Daisuke Nakane
- Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Tokyo, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Makoto Miyata
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka Metropolitan University, Sumiyoshi-ku, Osaka, Japan
- Graduate School of Science, Osaka Metropolitan University, Sumiyoshi-ku, Osaka, Japan
| | - Mark J McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201, USA
| | - Koji Nakayama
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
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11
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Brüser T, Mehner-Breitfeld D. Occurrence and potential mechanism of holin-mediated non-lytic protein translocation in bacteria. MICROBIAL CELL (GRAZ, AUSTRIA) 2022; 9:159-173. [PMID: 36262927 PMCID: PMC9527704 DOI: 10.15698/mic2022.10.785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/13/2022] [Accepted: 09/15/2022] [Indexed: 11/13/2022]
Abstract
Holins are generally believed to generate large membrane lesions that permit the passage of endolysins across the cytoplasmic membrane of prokaryotes, ultimately resulting in cell wall degradation and cell lysis. However, there are more and more examples known for non-lytic holin-dependent secretion of proteins by bacteria, indicating that holins somehow can transport proteins without causing large membrane lesions. Phage-derived holins can be used for a non-lytic endolysin translocation to permeabilize the cell wall for the passage of secreted proteins. In addition, clostridia, which do not possess the Tat pathway for transport of folded proteins, most likely employ non-lytic holin-mediated transport also for secretion of toxins and bacteriocins that are incompatible with the general Sec pathway. The mechanism for non-lytic holin-mediated transport is unknown, but the recent finding that the small holin TpeE mediates a non-lytic toxin secretion in Clostridium perfringens opened new perspectives. TpeE contains only one short transmembrane helix that is followed by an amphipathic helix, which is reminiscent of TatA, the membrane-permeabilizing component of the Tat translocon for folded proteins. Here we review the known cases of non-lytic holin-mediated transport and then focus on the structural and functional comparison of TatA and TpeE, resulting in a mechanistic model for holin-mediated transport. This model is strongly supported by a so far not recognized naturally occurring holin-endolysin fusion protein.
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Affiliation(s)
- Thomas Brüser
- Institute of Microbiology, Leibniz Universität Hannover, Hannover, Germany
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12
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Song L, Perpich JD, Wu C, Doan T, Nowakowska Z, Potempa J, Christie PJ, Cascales E, Lamont RJ, Hu B. A unique bacterial secretion machinery with multiple secretion centers. Proc Natl Acad Sci U S A 2022; 119:e2119907119. [PMID: 35471908 PMCID: PMC9170169 DOI: 10.1073/pnas.2119907119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/22/2022] [Indexed: 11/18/2022] Open
Abstract
The Porphyromonas gingivalis type IX secretion system (T9SS) promotes periodontal disease by secreting gingipains and other virulence factors. By in situ cryoelectron tomography, we report that the P. gingivalis T9SS consists of 18 PorM dimers arranged as a large, caged ring in the periplasm. Near the outer membrane, PorM dimers interact with a PorKN ring complex of ∼52 nm in diameter. PorMKN translocation complexes of a given T9SS adopt distinct conformations energized by the proton motive force, suggestive of different activation states. At the inner membrane, PorM associates with a cytoplasmic complex that exhibits 12-fold symmetry and requires both PorM and PorL for assembly. Activated motors deliver substrates across the outer membrane via one of eight Sov translocons arranged in a ring. The T9SSs are unique among known secretion systems in bacteria and eukaryotes in their assembly as supramolecular machines composed of apparently independently functioning translocation motors and export pores.
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Affiliation(s)
- Liqiang Song
- Department of Microbiology and Molecular Genetics, McGovern Medical School, Houston, TX 77030
| | - John D. Perpich
- Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, KY 40292
| | - Chenggang Wu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, Houston, TX 77030
| | - Thierry Doan
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, CNRS UMR7255, Aix-Marseille Université, Marseille, 13402 France
| | - Zuzanna Nowakowska
- Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Krakow, 30-387 Poland
| | - Jan Potempa
- Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, KY 40292
- Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Krakow, 30-387 Poland
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, Houston, TX 77030
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, CNRS UMR7255, Aix-Marseille Université, Marseille, 13402 France
| | - Richard J. Lamont
- Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, KY 40292
| | - Bo Hu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, Houston, TX 77030
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Rieu M, Krutyholowa R, Taylor NMI, Berry RM. A new class of biological ion-driven rotary molecular motors with 5:2 symmetry. Front Microbiol 2022; 13:948383. [PMID: 35992645 PMCID: PMC9389320 DOI: 10.3389/fmicb.2022.948383] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 07/04/2022] [Indexed: 11/15/2022] Open
Abstract
Several new structures of three types of protein complexes, obtained by cryo-electron microscopy (cryo-EM) and published between 2019 and 2021, identify a new family of natural molecular wheels, the "5:2 rotary motors." These span the cytoplasmic membranes of bacteria, and their rotation is driven by ion flow into the cell. They consist of a pentameric wheel encircling a dimeric axle within the cytoplasmic membrane of both Gram-positive and gram-negative bacteria. The axles extend into the periplasm, and the wheels extend into the cytoplasm. Rotation of these wheels has never been observed directly; it is inferred from the symmetry of the complexes and from the roles they play within the larger systems that they are known to power. In particular, the new structure of the stator complex of the Bacterial Flagellar Motor, MotA5B2, is consistent with a "wheels within wheels" model of the motor. Other 5:2 rotary motors are believed to share the core rotary function and mechanism, driven by ion-motive force at the cytoplasmic membrane. Their structures diverge in their periplasmic and cytoplasmic parts, reflecting the variety of roles that they perform. This review focuses on the structures of 5:2 rotary motors and their proposed mechanisms and functions. We also discuss molecular rotation in general and its relation to the rotational symmetry of molecular complexes.
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Affiliation(s)
- Martin Rieu
- Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building University of Oxford, Oxford, United Kingdom
| | - Roscislaw Krutyholowa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Nicholas M. I. Taylor
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
- Nicholas M. I. Taylor,
| | - Richard M. Berry
- Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building University of Oxford, Oxford, United Kingdom
- *Correspondence: Richard M. Berry,
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