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Su C, Zhong Y, Zhou Z, Li Y, Jia Y, Xie S, Zhao J, Miao H, Luo H, Li Z, Shi Z, Li L, Song X. Structural insights into the Caprin-2 HR1 domain in canonical Wnt signaling. J Biol Chem 2024:107694. [PMID: 39159816 DOI: 10.1016/j.jbc.2024.107694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 07/31/2024] [Accepted: 08/09/2024] [Indexed: 08/21/2024] Open
Abstract
The canonical Wnt signaling pathway plays crucial roles in cell fate decisions as well as in pathogenesis of various diseases. Previously, we reported Caprin-2 as a new regulator of canonical Wnt signaling through a mechanism of facilitating LRP5/6 phosphorylation. Here, we resolved the crystal structure of the N-terminal homologous region 1 (HR1) domain of human Caprin-2 (hCap2_HR1). HR1 domain is so far only observed in Caprin-2 and its homologous protein Caprin-1, and the function of this domain remains largely mysterious. Here, the structure showed that hCap2_HR1 forms a homo-dimer and exhibits an overall structure roughly resembling the appearance of a pair of scissors. Moreover, we found that residues R200 and R201, which located at a basic cluster within the N-terminal "blades" region, are critical for Caprin-2's localization to the plasma membrane. In line with this, mutations targeting these two residues decrease Caprin-2's activity in the canonical Wnt signaling. Overall, we characterized a previously unknown "scissors"-like structure of the full-length HR1 domain, and revealed its function in mediating Caprin-2's localization to the plasma membrane.
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Affiliation(s)
- Chun Su
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - YuCheng Zhong
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
| | - Zhilei Zhou
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yongtao Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yingying Jia
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Sichun Xie
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jianfei Zhao
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Haofei Miao
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Huilian Luo
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhenyan Li
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
| | - Zhubin Shi
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, China
| | - Lin Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China; Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China.
| | - Xiaomin Song
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China.
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Ribardo DA, Johnson JJ, Hendrixson DR. Viscosity-dependent determinants of Campylobacter jejuni impacting the velocity of flagellar motility. mBio 2024; 15:e0254423. [PMID: 38085029 PMCID: PMC10790790 DOI: 10.1128/mbio.02544-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 11/06/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE Bacteria can adapt flagellar motor output in response to the load that the extracellular milieu imparts on the flagellar filament to enable propulsion. Bacteria can adapt flagellar motor output in response to the load that the extracellular milieu imparts on the flagellar filament to enable propulsion through diverse environments. These changes may involve increasing power and torque in high-viscosity environments or reducing power and flagellar rotation upon contact with a surface. C. jejuni swimming velocity in low-viscosity environments is comparable to other bacterial flagellates and increases significantly as external viscosity increases. In this work, we provide evidence that the mechanics of the C. jejuni flagellar motor has evolved to naturally promote high swimming velocity in high-viscosity environments. We found that C. jejuni produces VidA and VidB as auxiliary proteins to specifically affect flagellar motor activity in low viscosity to reduce swimming velocity. Our findings provide some of the first insights into different mechanisms that exist in bacteria to alter the mechanics of a flagellar motor, depending on the viscosity of extracellular environments.
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Affiliation(s)
- Deborah A. Ribardo
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jeremiah J. Johnson
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - David R. Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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3
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Minamino T, Kinoshita M. Structure, Assembly, and Function of Flagella Responsible for Bacterial Locomotion. EcoSal Plus 2023; 11:eesp00112023. [PMID: 37260402 PMCID: PMC10729930 DOI: 10.1128/ecosalplus.esp-0011-2023] [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: 01/18/2023] [Accepted: 04/14/2023] [Indexed: 01/28/2024]
Abstract
Many motile bacteria use flagella for locomotion under a variety of environmental conditions. Because bacterial flagella are under the control of sensory signal transduction pathways, each cell is able to autonomously control its flagellum-driven locomotion and move to an environment favorable for survival. The flagellum of Salmonella enterica serovar Typhimurium is a supramolecular assembly consisting of at least three distinct functional parts: a basal body that acts as a bidirectional rotary motor together with multiple force generators, each of which serves as a transmembrane proton channel to couple the proton flow through the channel with torque generation; a filament that functions as a helical propeller that produces propulsion; and a hook that works as a universal joint that transmits the torque produced by the rotary motor to the helical propeller. At the base of the flagellum is a type III secretion system that transports flagellar structural subunits from the cytoplasm to the distal end of the growing flagellar structure, where assembly takes place. In recent years, high-resolution cryo-electron microscopy (cryoEM) image analysis has revealed the overall structure of the flagellum, and this structural information has made it possible to discuss flagellar assembly and function at the atomic level. In this article, we describe what is known about the structure, assembly, and function of Salmonella flagella.
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Affiliation(s)
- Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
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4
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Worrall LJ, Majewski DD, Strynadka NCJ. Structural Insights into Type III Secretion Systems of the Bacterial Flagellum and Injectisome. Annu Rev Microbiol 2023; 77:669-698. [PMID: 37713458 DOI: 10.1146/annurev-micro-032521-025503] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/17/2023]
Abstract
Two of the most fascinating bacterial nanomachines-the broadly disseminated rotary flagellum at the heart of cellular motility and the eukaryotic cell-puncturing injectisome essential to specific pathogenic species-utilize at their core a conserved export machinery called the type III secretion system (T3SS). The T3SS not only secretes the components that self-assemble into their extracellular appendages but also, in the case of the injectisome, subsequently directly translocates modulating effector proteins from the bacterial cell into the infected host. The injectisome is thought to have evolved from the flagellum as a minimal secretory system lacking motility, with the subsequent acquisition of additional components tailored to its specialized role in manipulating eukaryotic hosts for pathogenic advantage. Both nanomachines have long been the focus of intense interest, but advances in structural and functional understanding have taken a significant step forward since 2015, facilitated by the revolutionary advances in cryo-electron microscopy technologies. With several seminal structures of each nanomachine now captured, we review here the molecular similarities and differences that underlie their diverse functions.
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Affiliation(s)
- Liam J Worrall
- Department of Biochemistry and Molecular Biology and Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada; , ,
| | - Dorothy D Majewski
- Department of Biochemistry and Molecular Biology and Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada; , ,
- Current affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada; , ,
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5
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Hu G, Wang Y, Blake C, Nordgaard M, Liu X, Wang B, Kovács ÁT. Parallel genetic adaptation of Bacillus subtilis to different plant species. Microb Genom 2023; 9:mgen001064. [PMID: 37466402 PMCID: PMC10438812 DOI: 10.1099/mgen.0.001064] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 06/16/2023] [Indexed: 07/20/2023] Open
Abstract
Plant growth-promoting rhizobacteria benefit plants by stimulating their growth or protecting them against phytopathogens. Rhizobacteria must colonize and persist on plant roots to exert their benefits. However, little is known regarding the processes by which rhizobacteria adapt to different plant species, or behave under alternating host plant regimes. Here, we used experimental evolution and whole-population whole-genome sequencing to analyse how Bacillus subtilis evolves on Arabidopsis thaliana and tomato seedlings, and under an alternating host plant regime, in a static hydroponic setup. We observed parallel evolution across multiple levels of biological organization in all conditions, which was greatest for the two heterogeneous, multi-resource, spatially structured environments at the genetic level. Species-specific adaptation at the genetic level was also observed, possibly caused by the selection stress imposed by different host plants. Furthermore, a trade-off between motility and biofilm development was supported by mutational changes in motility- and biofilm-related genes. Finally, we identified several condition-specific and common targeted genes in different environments by comparing three different B. subtilis biofilm adaptation settings. The results demonstrate a common evolutionary pattern when B. subtilis is adapting to the plant rhizosphere in similar conditions, and reveal differences in genetic mechanisms between different host plants. These findings will likely support strain improvements for sustainable agriculture.
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Affiliation(s)
- Guohai Hu
- China National GeneBank, BGI-Shenzhen, Shenzhen 518120, PR China
- BGI-Shenzhen, Shenzhen 518083, PR China
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Yue Wang
- China National GeneBank, BGI-Shenzhen, Shenzhen 518120, PR China
- BGI-Shenzhen, Shenzhen 518083, PR China
- BGI-Beijing, Beijing 102601, PR China
| | - Christopher Blake
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Mathilde Nordgaard
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Xin Liu
- China National GeneBank, BGI-Shenzhen, Shenzhen 518120, PR China
- BGI-Shenzhen, Shenzhen 518083, PR China
- BGI-Beijing, Beijing 102601, PR China
| | - Bo Wang
- China National GeneBank, BGI-Shenzhen, Shenzhen 518120, PR China
- BGI-Shenzhen, Shenzhen 518083, PR China
- Shenzhen Key Laboratory of Environmental Microbial Genomics and Application, BGI Shenzhen, 518083 Shenzhen, PR China
| | - Ákos T. Kovács
- Bacterial Interactions and Evolution Group, DTU Bioengineering, Technical University of Denmark, 2800 Lyngby, Denmark
- Institute of Biology Leiden, Leiden University, 2333BE Leiden, Netherlands
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6
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Gao D, Li H, Shao J, He L, Fu C, Lai H, O'Neill Rothenberg D, Xu X, Song G, Deng X, Cui ZN. Novel Ethyl-3-Aryl-2-Nitroacrylate Derivatives as Potential T3SS Inhibitors against Xanthomonas oryzae pv. oryzae on Rice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023. [PMID: 37285515 DOI: 10.1021/acs.jafc.3c00838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a highly destructive bacterial disease. Traditional prevention methods have utilized antibiotics to target bacterial growth, which has accelerated the emergence of resistant strains. New prevention techniques are developing agents such as type III secretion system (T3SS) inhibitors that target bacterial virulence factors without affecting bacterial growth. To explore novel T3SS inhibitors, a series of ethyl-3-aryl-2-nitroacrylate derivatives were designed and synthesized. Preliminary screening of T3SS inhibitors was based on the inhibition of the hpa1 gene promoter and showed no effect on bacterial growth. Compounds B9 and B10, obtained in the primary screening, significantly inhibited the hypersensitive response (HR) in tobacco and the expression of T3SS genes in the hrp cluster including key regulatory genes. In vivo bioassays showed that T3SS inhibitors obviously inhibited BLB and appeared to be more effective when combined with quorum quenching bacteria F20.
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Affiliation(s)
- Dongni Gao
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Hui Li
- College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
| | - Jiang Shao
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Lulu He
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Chen Fu
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Hongyu Lai
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | | | - Xiaoli Xu
- Instrumental Analysis & Research Center, South China Agricultural University, Guangzhou 510642, China
| | - Gaopeng Song
- College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
| | - Zi-Ning Cui
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
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7
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Rossi P, Xing Q, Bini E, Portaliou AG, Clay MC, Warren EM, Khanra NK, Economou A, Kalodimos CG. Chaperone Recycling in Late-Stage Flagellar Assembly. J Mol Biol 2023; 435:167954. [PMID: 37330284 PMCID: PMC10471782 DOI: 10.1016/j.jmb.2023.167954] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/30/2022] [Accepted: 01/03/2023] [Indexed: 06/19/2023]
Abstract
The flagellum is a sophisticated nanomachine responsible for motility in Gram-negative bacteria. Flagellar assembly is a strictly choreographed process, in which the motor and export gate are formed first, followed by the extracellular propeller structure. Extracellular flagellar components are escorted to the export gate by dedicated molecular chaperones for secretion and self-assembly at the apex of the emerging structure. The detailed mechanisms of chaperone-substrate trafficking at the export gate remain poorly understood. Here, we structurally characterized the interaction of Salmonella enterica late-stage flagellar chaperones FliT and FlgN with the export controller protein FliJ. Previous studies showed that FliJ is absolutely required for flagellar assembly since its interaction with chaperone-client complexes controls substrate delivery to the export gate. Our biophysical and cell-based data show that FliT and FlgN bind FliJ cooperatively, with high affinity and on specific sites. Chaperone binding completely disrupts the FliJ coiled-coil structure and alters its interactions with the export gate. We propose that FliJ aids the release of substrates from the chaperone and forms the basis of chaperone recycling during late-stage flagellar assembly.
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Affiliation(s)
- Paolo Rossi
- Deparment of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, United States
| | - Qiong Xing
- State Key Laboratory of Bio-catalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430074, China
| | - Elisabetta Bini
- Deparment of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, United States
| | - Athina G Portaliou
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Mary C Clay
- Deparment of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, United States
| | - Eric M Warren
- Deparment of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, United States
| | - Nandish K Khanra
- Deparment of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, United States
| | - Anastassios Economou
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Charalampos G Kalodimos
- Deparment of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, United States.
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8
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Minamino T, Kinoshita M, Morimoto YV, Namba K. Activation mechanism of the bacterial flagellar dual-fuel protein export engine. Biophys Physicobiol 2022; 19:e190046. [PMID: 36567733 PMCID: PMC9751260 DOI: 10.2142/biophysico.bppb-v19.0046] [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: 11/01/2022] [Accepted: 11/17/2022] [Indexed: 11/19/2022] Open
Abstract
Bacteria employ the flagellar type III secretion system (fT3SS) to construct flagellum, which acts as a supramolecular motility machine. The fT3SS of Salmonella enterica serovar Typhimurium is composed of a transmembrane export gate complex and a cytoplasmic ATPase ring complex. The transmembrane export gate complex is fueled by proton motive force across the cytoplasmic membrane and is divided into four distinct functional parts: a dual-fuel export engine; a polypeptide channel; a membrane voltage sensor; and a docking platform. ATP hydrolysis by the cytoplasmic ATPase complex converts the export gate complex into a highly efficient proton (H+)/protein antiporter that couples inward-directed H+ flow with outward-directed protein export. When the ATPase ring complex does not work well in a given environment, the export gate complex will remain inactive. However, when the electric potential difference, which is defined as membrane voltage, rises above a certain threshold value, the export gate complex becomes an active H+/protein antiporter to a considerable degree, suggesting that the export gate complex has a voltage-gated activation mechanism. Furthermore, the export gate complex also has a sodium ion (Na+) channel to couple Na+ influx with flagellar protein export. In this article, we review our current understanding of the activation mechanism of the dual-fuel protein export engine of the fT3SS. This review article is an extended version of a Japanese article, Membrane voltage-dependent activation of the transmembrane export gate complex in the bacterial flagellar type III secretion system, published in SEIBUTSU BUTSURI Vol. 62, p165-169 (2022).
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Affiliation(s)
- Tohru Minamino
- Graduate school of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Miki Kinoshita
- Graduate school of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yusuke V. Morimoto
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan,Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Keiichi Namba
- Graduate school of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan,RIKEN SPring-8 Center, Suita, Osaka 565-0871, Japan,JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, Suita, Osaka 565-0871, Japan
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9
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Wang LK, Sun SS, Zhang SY, Nie P, Xie HX. Orf1B controls secretion of T3SS proteins and contributes to Edwardsiella piscicida adhesion to epithelial cells. Vet Res 2022; 53:40. [PMID: 35692056 PMCID: PMC9190107 DOI: 10.1186/s13567-022-01057-6] [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: 02/02/2022] [Accepted: 04/12/2022] [Indexed: 11/26/2022] Open
Abstract
Edwardsiella piscicida is a Gram-negative enteric pathogen that causes hemorrhagic septicemia in fish. The type III secretion system (T3SS) is one of its two most important virulence islands. T3SS protein EseJ inhibits E. piscicida adhesion to epithelioma papillosum cyprini (EPC) cells by negatively regulating type 1 fimbria. Type 1 fimbria helps E. piscicida to adhere to fish epithelial cells. In this study, we characterized a functional unknown protein (Orf1B) encoded within the T3SS gene cluster of E. piscicida. This protein consists of 122 amino acids, sharing structural similarity with YscO in Vibrio parahaemolyticus. Orf1B controls secretion of T3SS translocon and effectors in E. piscicida. By immunoprecipitation, Orf1B was shown to interact with T3SS ATPase EsaN. This interaction may contribute to the assembly of the ATPase complex, which energizes the secretion of T3SS proteins. Moreover, disruption of Orf1B dramatically decreased E. piscicida adhesion to EPC cells due to the increased steady-state protein level of EseJ within E. piscicida. Taken together, this study partially unraveled the mechanisms through which Orf1B promotes secretion of T3SS proteins and contributes to E. piscicida adhesion. This study helps to improve our understanding on molecular mechanism of E. piscicida pathogenesis.
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Affiliation(s)
- Long Kun Wang
- Dalian Ocean University, Dalian, 116023, Liaoning, China.,State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, Hubei, China
| | - Shan Shan Sun
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, Hubei, China.,College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Shu Ya Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, Hubei, China.,College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Pin Nie
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, Hubei, China
| | - Hai Xia Xie
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, Hubei, China.
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10
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Minamino T, Kinoshita M, Namba K. Insight Into Distinct Functional Roles of the Flagellar ATPase Complex for Flagellar Assembly in Salmonella. Front Microbiol 2022; 13:864178. [PMID: 35602071 PMCID: PMC9114704 DOI: 10.3389/fmicb.2022.864178] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/13/2022] [Indexed: 11/13/2022] Open
Abstract
Most motile bacteria utilize the flagellar type III secretion system (fT3SS) to construct the flagellum, which is a supramolecular motility machine consisting of basal body rings and an axial structure. Each axial protein is translocated via the fT3SS across the cytoplasmic membrane, diffuses down the central channel of the growing flagellar structure and assembles at the distal end. The fT3SS consists of a transmembrane export complex and a cytoplasmic ATPase ring complex with a stoichiometry of 12 FliH, 6 FliI and 1 FliJ. This complex is structurally similar to the cytoplasmic part of the FOF1 ATP synthase. The export complex requires the FliH12-FliI6-FliJ1 ring complex to serve as an active protein transporter. The FliI6 ring has six catalytic sites and hydrolyzes ATP at an interface between FliI subunits. FliJ binds to the center of the FliI6 ring and acts as the central stalk to activate the export complex. The FliH dimer binds to the N-terminal domain of each of the six FliI subunits and anchors the FliI6-FliJ1 ring to the base of the flagellum. In addition, FliI exists as a hetero-trimer with the FliH dimer in the cytoplasm. The rapid association-dissociation cycle of this hetero-trimer with the docking platform of the export complex promotes sequential transfer of export substrates from the cytoplasm to the export gate for high-speed protein transport. In this article, we review our current understanding of multiple roles played by the flagellar cytoplasmic ATPase complex during efficient flagellar assembly.
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Affiliation(s)
- Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.,RIKEN SPring-8 Center and Center for Biosystems Dynamics Research, Osaka, Japan.,JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, Osaka, Japan
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11
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Cirino G, Szabo C, Papapetropoulos A. Physiological roles of hydrogen sulfide in mammalian cells, tissues and organs. Physiol Rev 2022; 103:31-276. [DOI: 10.1152/physrev.00028.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
H2S belongs to the class of molecules known as gasotransmitters, which also includes nitric oxide (NO) and carbon monoxide (CO). Three enzymes are recognized as endogenous sources of H2S in various cells and tissues: cystathionine g-lyase (CSE), cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). The current article reviews the regulation of these enzymes as well as the pathways of their enzymatic and non-enzymatic degradation and elimination. The multiple interactions of H2S with other labile endogenous molecules (e.g. NO) and reactive oxygen species are also outlined. The various biological targets and signaling pathways are discussed, with special reference to H2S and oxidative posttranscriptional modification of proteins, the effect of H2S on channels and intracellular second messenger pathways, the regulation of gene transcription and translation and the regulation of cellular bioenergetics and metabolism. The pharmacological and molecular tools currently available to study H2S physiology are also reviewed, including their utility and limitations. In subsequent sections, the role of H2S in the regulation of various physiological and cellular functions is reviewed. The physiological role of H2S in various cell types and organ systems are overviewed. Finally, the role of H2S in the regulation of various organ functions is discussed as well as the characteristic bell-shaped biphasic effects of H2S. In addition, key pathophysiological aspects, debated areas, and future research and translational areas are identified A wide array of significant roles of H2S in the physiological regulation of all organ functions emerges from this review.
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Affiliation(s)
- Giuseppe Cirino
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Naples, Italy
| | - Csaba Szabo
- Chair of Pharmacology, Section of Medicine, University of Fribourg, Switzerland
| | - Andreas Papapetropoulos
- Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece & Clinical, Experimental Surgery and Translational Research Center, Biomedical Research Foundation of the Academy of Athens, Greece
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12
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Xu J, Wang J, Liu A, Zhang Y, Gao X. Structural and Functional Analysis of SsaV Cytoplasmic Domain and Variable Linker States in the Context of the InvA-SsaV Chimeric Protein. Microbiol Spectr 2021; 9:e0125121. [PMID: 34851139 PMCID: PMC8635156 DOI: 10.1128/spectrum.01251-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 11/05/2021] [Indexed: 11/20/2022] Open
Abstract
The type III secretion (T3S) injectisome is a syringe-like protein-delivery nanomachine widely utilized by Gram-negative bacteria. It can deliver effector proteins directly from bacteria into eukaryotic host cells, which is crucial for the bacterial-host interaction. Intracellular pathogen Salmonella enterica serovar Typhimurium encodes two sets of T3S injectisomes from Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2), which are critical for its host invasion and intracellular survival, respectively. The inner membrane export gate protein, SctV (InvA in SPI-1 and SsaV in SPI-2), is the largest component of the injectisome and is essential for assembly and function of T3SS. Here, we report the 2.11 Å cryo-EM structure of the SsaV cytoplasmic domain (SsaVC) in the context of a full-length SctV chimera consisting of the transmembrane region of InvA, the linker of SsaV (SsaVL) and SsaVC. The structural analysis shows that SsaVC exists in a semi-open state and SsaVL exhibits two major orientations, implying a highly dynamic process of SsaV for the substrate selection and secretion in a full-length context. A biochemical assay indicates that SsaVL plays an essential role in maintaining the nonameric state of SsaV. This study offers near atomic-level insights into how SsaVC and SsaVL facilitate the assembly and function of SsaV and may lead to the development of potential anti-virulence therapeutics against T3SS-mediated bacterial infection. IMPORTANCE Type III secretion system (T3SS) is a multicomponent nanomachine and a critical virulence factor for a wide range of Gram-negative bacterial pathogens. It can deliver numbers of effectors into the host cell to facilitate the bacterial host infection. Export gate protein SctV, as one of the engines of T3SS, is at the center of T3SS assembly and function. In this study, we show the high-resolution atomic structure of the cytosolic domain of SctV in the nonameric state with variable linker conformations. Our first observation of conformational changes of the linker region of SctV and the semi-open state of the cytosolic domain of SctV in the full-length context further support that the substrate selection and secretion process of SctV is highly dynamic. These findings have important implications for the development of therapeutic strategies targeting SctV to combat T3SS-mediated bacterial infection.
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Affiliation(s)
- Jinghua Xu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Jiuqing Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Aijun Liu
- Shanghai Fifth People's Hospital and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Yanqing Zhang
- Shanghai Fifth People's Hospital and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Xiang Gao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
- School of Life Sciences, Shandong University, Qingdao, China
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13
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Bryant OJ, Fraser GM. Regulation of bacterial Type III Secretion System export gate opening by substrates and the FliJ stalk of the flagellar ATPase. FEBS J 2021; 289:2628-2641. [PMID: 34812581 DOI: 10.1111/febs.16294] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 09/13/2021] [Accepted: 11/22/2021] [Indexed: 01/12/2023]
Abstract
Type III Secretion Systems (T3SS) transport proteins from the bacterial cytosol for assembly into cell surface nanomachines or direct delivery into target eukaryotic cells. At the core of the flagellar T3SS, the FlhAB-FliPQR export gate regulates protein entry into the export channel whilst maintaining the integrity of the cell membrane. Here, we identify critical residues in the export gate FliR plug that stabilise the closed conformation, preserving the membrane permeability barrier, and we show that the gate opens and closes in response to export substrate availability. Our data indicate that FlhAB-FliPQR gate opening, which is triggered by substrate export signals, is energised by FlhA in a proton motive force-dependent manner. We present evidence that the export substrate and the FliJ stalk of the flagellar ATPase provide mechanistically distinct, non-redundant gate-activating signals that are critical for efficient export.
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14
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Structural Dynamics of the Functional Nonameric Type III Translocase Export Gate. J Mol Biol 2021; 433:167188. [PMID: 34454944 DOI: 10.1016/j.jmb.2021.167188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 11/20/2022]
Abstract
Type III protein secretion is widespread in Gram-negative pathogens. It comprises the injectisome with a surface-exposed needle and an inner membrane translocase. The translocase contains the SctRSTU export channel enveloped by the export gate subunit SctV that binds chaperone/exported clients and forms a putative ante-chamber. We probed the assembly, function, structure and dynamics of SctV from enteropathogenic E. coli (EPEC). In both EPEC and E. coli lab strains, SctV forms peripheral oligomeric clusters that are detergent-extracted as homo-nonamers. Membrane-embedded SctV9 is necessary and sufficient to act as a receptor for different chaperone/exported protein pairs with distinct C-domain binding sites that are essential for secretion. Negative staining electron microscopy revealed that peptidisc-reconstituted His-SctV9 forms a tripartite particle of ∼22 nm with a N-terminal domain connected by a short linker to a C-domain ring structure with a ∼5 nm-wide inner opening. The isolated C-domain ring was resolved with cryo-EM at 3.1 Å and structurally compared to other SctV homologues. Its four sub-domains undergo a three-stage "pinching" motion. Hydrogen-deuterium exchange mass spectrometry revealed this to involve dynamic and rigid hinges and a hyper-flexible sub-domain that flips out of the ring periphery and binds chaperones on and between adjacent protomers. These motions are coincident with local conformational changes at the pore surface and ring entry mouth that may also be modulated by the ATPase inner stalk. We propose that the intrinsic dynamics of the SctV protomer are modulated by chaperones and the ATPase and could affect allosterically the other subunits of the nonameric ring during secretion.
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15
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Bryant OJ, Chung BYW, Fraser GM. Chaperone-mediated coupling of subunit availability to activation of flagellar Type III secretion. Mol Microbiol 2021; 116:538-549. [PMID: 33893668 DOI: 10.1111/mmi.14731] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 04/19/2021] [Indexed: 01/07/2023]
Abstract
Bacterial flagellar subunits are exported across the cell membrane by the flagellar Type III Secretion System (fT3SS), powered by the proton motive force (pmf) and a specialized ATPase that enables the flagellar export gate to utilize the pmf electric potential (ΔΨ). Export gate activation is mediated by the ATPase stalk, FliJ, but how this process is regulated to prevent wasteful dissipation of pmf in the absence of subunit cargo is not known. Here, we show that FliJ activation of the export gate is regulated by flagellar export chaperones. FliJ binds unladen chaperones and, by using novel chaperone variants specifically defective for FliJ binding, we show that disruption of this interaction attenuates motility and cognate subunit export. We demonstrate in vitro that chaperones and the FlhA export gate component compete for binding to FliJ, and show in vivo that unladen chaperones, which would be present in the cell when subunit levels are low, sequester FliJ to prevent activation of the export gate and attenuate subunit export. Our data indicate a mechanism whereby chaperones couple availability of subunit cargo to pmf-driven export by the fT3SS.
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Affiliation(s)
- Owain J Bryant
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Betty Y-W Chung
- Department of Pathology, University of Cambridge, Cambridge, UK
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16
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Bacterial Flagellar Filament: A Supramolecular Multifunctional Nanostructure. Int J Mol Sci 2021; 22:ijms22147521. [PMID: 34299141 PMCID: PMC8306008 DOI: 10.3390/ijms22147521] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/06/2021] [Accepted: 07/10/2021] [Indexed: 02/07/2023] Open
Abstract
The bacterial flagellum is a complex and dynamic nanomachine that propels bacteria through liquids. It consists of a basal body, a hook, and a long filament. The flagellar filament is composed of thousands of copies of the protein flagellin (FliC) arranged helically and ending with a filament cap composed of an oligomer of the protein FliD. The overall structure of the filament core is preserved across bacterial species, while the outer domains exhibit high variability, and in some cases are even completely absent. Flagellar assembly is a complex and energetically costly process triggered by environmental stimuli and, accordingly, highly regulated on transcriptional, translational and post-translational levels. Apart from its role in locomotion, the filament is critically important in several other aspects of bacterial survival, reproduction and pathogenicity, such as adhesion to surfaces, secretion of virulence factors and formation of biofilms. Additionally, due to its ability to provoke potent immune responses, flagellins have a role as adjuvants in vaccine development. In this review, we summarize the latest knowledge on the structure of flagellins, capping proteins and filaments, as well as their regulation and role during the colonization and infection of the host.
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17
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Minamino T, Morimoto YV, Kinoshita M, Namba K. Membrane voltage-dependent activation mechanism of the bacterial flagellar protein export apparatus. Proc Natl Acad Sci U S A 2021; 118:e2026587118. [PMID: 34035173 PMCID: PMC8179193 DOI: 10.1073/pnas.2026587118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The proton motive force (PMF) consists of the electric potential difference (Δψ), which is measured as membrane voltage, and the proton concentration difference (ΔpH) across the cytoplasmic membrane. The flagellar protein export machinery is composed of a PMF-driven transmembrane export gate complex and a cytoplasmic ATPase ring complex consisting of FliH, FliI, and FliJ. ATP hydrolysis by the FliI ATPase activates the export gate complex to become an active protein transporter utilizing Δψ to drive proton-coupled protein export. An interaction between FliJ and a transmembrane ion channel protein, FlhA, is a critical step for Δψ-driven protein export. To clarify how Δψ is utilized for flagellar protein export, we analyzed the export properties of the export gate complex in the absence of FliH and FliI. The protein transport activity of the export gate complex was very low at external pH 7.0 but increased significantly with an increase in Δψ by an upward shift of external pH from 7.0 to 8.5. This observation suggests that the export gate complex is equipped with a voltage-gated mechanism. An increase in the cytoplasmic level of FliJ and a gain-of-function mutation in FlhA significantly reduced the Δψ dependency of flagellar protein export by the export gate complex. However, deletion of FliJ decreased Δψ-dependent protein export significantly. We propose that Δψ is required for efficient interaction between FliJ and FlhA to open the FlhA ion channel to conduct protons to drive flagellar protein export in a Δψ-dependent manner.
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Affiliation(s)
- Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan;
| | - Yusuke V Morimoto
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka 820-8502, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
| | - Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan;
- SPring-8 Center, RIKEN, Osaka 565-0871, Japan
- Center for Biosystems Dynamics Research, RIKEN, Osaka 565-0871, Japan
- JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, Osaka 565-0871, Japan
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18
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Medina Munoz M, Brenner C, Richmond D, Spencer N, Rio RVM. The holobiont transcriptome of teneral tsetse fly species of varying vector competence. BMC Genomics 2021; 22:400. [PMID: 34058984 PMCID: PMC8166097 DOI: 10.1186/s12864-021-07729-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 05/21/2021] [Indexed: 12/13/2022] Open
Abstract
Background Tsetse flies are the obligate vectors of African trypanosomes, which cause Human and Animal African Trypanosomiasis. Teneral flies (newly eclosed adults) are especially susceptible to parasite establishment and development, yet our understanding of why remains fragmentary. The tsetse gut microbiome is dominated by two Gammaproteobacteria, an essential and ancient mutualist Wigglesworthia glossinidia and a commensal Sodalis glossinidius. Here, we characterize and compare the metatranscriptome of teneral Glossina morsitans to that of G. brevipalpis and describe unique immunological, physiological, and metabolic landscapes that may impact vector competence differences between these two species. Results An active expression profile was observed for Wigglesworthia immediately following host adult metamorphosis. Specifically, ‘translation, ribosomal structure and biogenesis’ followed by ‘coenzyme transport and metabolism’ were the most enriched clusters of orthologous genes (COGs), highlighting the importance of nutrient transport and metabolism even following host species diversification. Despite the significantly smaller Wigglesworthia genome more differentially expressed genes (DEGs) were identified between interspecific isolates (n = 326, ~ 55% of protein coding genes) than between the corresponding Sodalis isolates (n = 235, ~ 5% of protein coding genes) likely reflecting distinctions in host co-evolution and adaptation. DEGs between Sodalis isolates included genes involved in chitin degradation that may contribute towards trypanosome susceptibility by compromising the immunological protection provided by the peritrophic matrix. Lastly, G. brevipalpis tenerals demonstrate a more immunologically robust background with significant upregulation of IMD and melanization pathways. Conclusions These transcriptomic differences may collectively contribute to vector competence differences between tsetse species and offers translational relevance towards the design of novel vector control strategies. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07729-5.
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Affiliation(s)
- Miguel Medina Munoz
- Department of Biology, Eberly College of Arts and Sciences, West Virginia University, Morgantown, WV, 26505, USA
| | - Caitlyn Brenner
- Department of Biology, Washington and Jefferson College, Washington, PA, 15301, USA
| | - Dylan Richmond
- Department of Biology, Eberly College of Arts and Sciences, West Virginia University, Morgantown, WV, 26505, USA
| | - Noah Spencer
- Department of Biology, Eberly College of Arts and Sciences, West Virginia University, Morgantown, WV, 26505, USA
| | - Rita V M Rio
- Department of Biology, Eberly College of Arts and Sciences, West Virginia University, Morgantown, WV, 26505, USA.
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19
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Matzke NJ, Lin A, Stone M, Baker MAB. Flagellar export apparatus and ATP synthetase: Homology evidenced by synteny predating the Last Universal Common Ancestor. Bioessays 2021; 43:e2100004. [PMID: 33998015 DOI: 10.1002/bies.202100004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/01/2021] [Accepted: 04/21/2021] [Indexed: 11/07/2022]
Abstract
We report evidence further supporting homology between proteins in the F1 FO -ATP synthetase and the bacterial flagellar motor (BFM). BFM proteins FliH, FliI, and FliJ have been hypothesized to be homologous to FO -b + F1 -δ, F1 -α/β, and F1 -γ, with similar structure and interactions. We conduct a further test by constructing a gene order dataset, examining the order of fliH, fliI, and fliJ genes across the phylogenetic breadth of flagellar and nonflagellar type 3 secretion systems, and comparing this to published surveys of gene order in the F1 FO -ATP synthetase, its N-ATPase relatives, and the bacterial/archaeal V- and A-type ATPases. Strikingly, the fliHIJ gene order was deeply conserved, with the few exceptions appearing derived, and exactly matching the widely conserved F-ATPase gene order atpFHAG, coding for subunits b-δ-α-γ. The V/A-type ATPases have a similar conserved gene order. Our results confirm homology between these systems, and suggest a rare case of synteny conserved over billions of years, predating the Last Universal Common Ancestor (LUCA).
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Affiliation(s)
- Nicholas J Matzke
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Angela Lin
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Micaella Stone
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Matthew A B Baker
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia.,CSIRO Synthetic Biology Future Science Platform, Brisbane, Australia
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20
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Kinoshita M, Namba K, Minamino T. A positive charge region of Salmonella FliI is required for ATPase formation and efficient flagellar protein export. Commun Biol 2021; 4:464. [PMID: 33846530 PMCID: PMC8041783 DOI: 10.1038/s42003-021-01980-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 03/12/2021] [Indexed: 01/28/2023] Open
Abstract
The FliH2FliI complex is thought to pilot flagellar subunit proteins from the cytoplasm to the transmembrane export gate complex for flagellar assembly in Salmonella enterica. FliI also forms a homo-hexamer to hydrolyze ATP, thereby activating the export gate complex to become an active protein transporter. However, it remains unknown how this activation occurs. Here we report the role of a positively charged cluster formed by Arg-26, Arg-27, Arg-33, Arg-76 and Arg-93 of FliI in flagellar protein export. We show that Arg-33 and Arg-76 are involved in FliI ring formation and that the fliI(R26A/R27A/R33A/R76A/R93A) mutant requires the presence of FliH to fully exert its export function. We observed that gain-of-function mutations in FlhB increased the probability of substrate entry into the export gate complex, thereby restoring the export function of the ∆fliH fliI(R26A/R27A/R33A/R76A/R93A) mutant. We suggest that the positive charge cluster of FliI is responsible not only for well-regulated hexamer assembly but also for substrate entry into the gate complex. Kinoshita, Namba and Minamino show that a cluster of positively-charged arginines in the Salmonella FliI is necessary for formation of the FliI homo-hexamer ATPase. Through loss- and gain-of-function experiments, they demonstrate that hexamer assembly is also responsible for efficient export of flagellar proteins during flagellar assembly.
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Affiliation(s)
- Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan.,RIKEN SPring-8 Center and Center for Biosystems Dynamics Research, Suita, Osaka, Japan.,JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, Suita, Osaka, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan.
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21
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Morimoto YV, Minamino T. Architecture and Assembly of the Bacterial Flagellar Motor Complex. Subcell Biochem 2021; 96:297-321. [PMID: 33252734 DOI: 10.1007/978-3-030-58971-4_8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
One of the central systems responsible for bacterial motility is the flagellum. The bacterial flagellum is a macromolecular protein complex that is more than five times the cell length. Flagella-driven motility is coordinated via a chemosensory signal transduction pathway, and so bacterial cells sense changes in the environment and migrate towards more desirable locations. The flagellum of Salmonella enterica serovar Typhimurium is composed of a bi-directional rotary motor, a universal joint and a helical propeller. The flagellar motor, which structurally resembles an artificial motor, is embedded within the cell envelop and spins at several hundred revolutions per second. In contrast to an artificial motor, the energy utilized for high-speed flagellar motor rotation is the inward-directed proton flow through a transmembrane proton channel of the stator unit of the flagellar motor. The flagellar motor realizes efficient chemotaxis while performing high-speed movement by an ingenious directional switching mechanism of the motor rotation. To build the universal joint and helical propeller structures outside the cell body, the flagellar motor contains its own protein transporter called a type III protein export apparatus. In this chapter we summarize the structure and assembly of the Salmonella flagellar motor complex.
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Affiliation(s)
- Yusuke V Morimoto
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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22
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Protein Export via the Type III Secretion System of the Bacterial Flagellum. Biomolecules 2021; 11:biom11020186. [PMID: 33572887 PMCID: PMC7911332 DOI: 10.3390/biom11020186] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 12/15/2022] Open
Abstract
The bacterial flagellum and the related virulence-associated injectisome system of pathogenic bacteria utilize a type III secretion system (T3SS) to export substrate proteins across the inner membrane in a proton motive force-dependent manner. The T3SS is composed of an export gate (FliPQR/FlhA/FlhB) located in the flagellar basal body and an associated soluble ATPase complex in the cytoplasm (FliHIJ). Here, we summarise recent insights into the structure, assembly and protein secretion mechanisms of the T3SS with a focus on energy transduction and protein transport across the cytoplasmic membrane.
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23
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Zhuang XY, Lo CJ. Construction and Loss of Bacterial Flagellar Filaments. Biomolecules 2020; 10:E1528. [PMID: 33182435 PMCID: PMC7696725 DOI: 10.3390/biom10111528] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/26/2020] [Accepted: 11/04/2020] [Indexed: 11/16/2022] Open
Abstract
The bacterial flagellar filament is an extracellular tubular protein structure that acts as a propeller for bacterial swimming motility. It is connected to the membrane-anchored rotary bacterial flagellar motor through a short hook. The bacterial flagellar filament consists of approximately 20,000 flagellins and can be several micrometers long. In this article, we reviewed the experimental works and models of flagellar filament construction and the recent findings of flagellar filament ejection during the cell cycle. The length-dependent decay of flagellar filament growth data supports the injection-diffusion model. The decay of flagellar growth rate is due to reduced transportation of long-distance diffusion and jamming. However, the filament is not a permeant structure. Several bacterial species actively abandon their flagella under starvation. Flagellum is disassembled when the rod is broken, resulting in an ejection of the filament with a partial rod and hook. The inner membrane component is then diffused on the membrane before further breakdown. These new findings open a new field of bacterial macro-molecule assembly, disassembly, and signal transduction.
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Affiliation(s)
| | - Chien-Jung Lo
- Department of Physics and Graduate Institute of Biophysics, National Central University, Taoyuan City 32001, Taiwan;
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24
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Structural Conservation and Adaptation of the Bacterial Flagella Motor. Biomolecules 2020; 10:biom10111492. [PMID: 33138111 PMCID: PMC7693769 DOI: 10.3390/biom10111492] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 02/07/2023] Open
Abstract
Many bacteria require flagella for the ability to move, survive, and cause infection. The flagellum is a complex nanomachine that has evolved to increase the fitness of each bacterium to diverse environments. Over several decades, molecular, biochemical, and structural insights into the flagella have led to a comprehensive understanding of the structure and function of this fascinating nanomachine. Notably, X-ray crystallography, cryo-electron microscopy (cryo-EM), and cryo-electron tomography (cryo-ET) have elucidated the flagella and their components to unprecedented resolution, gleaning insights into their structural conservation and adaptation. In this review, we focus on recent structural studies that have led to a mechanistic understanding of flagellar assembly, function, and evolution.
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25
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Ngo TD, Perdu C, Jneid B, Ragno M, Novion Ducassou J, Kraut A, Couté Y, Stopford C, Attrée I, Rietsch A, Faudry E. The PopN Gate-keeper Complex Acts on the ATPase PscN to Regulate the T3SS Secretion Switch from Early to Middle Substrates in Pseudomonas aeruginosa. J Mol Biol 2020; 432:166690. [PMID: 33289667 DOI: 10.1016/j.jmb.2020.10.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/09/2020] [Accepted: 10/19/2020] [Indexed: 10/23/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic bacterium of which the main virulence factor is the Type III Secretion System. The ATPase of this machinery, PscN (SctN), is thought to be localized at the base of the secretion apparatus and to participate in the recognition, chaperone dissociation and unfolding of exported T3SS proteins. In this work, a protein-protein interaction ELISA revealed the interaction of PscN with a wide range of exported T3SS proteins including the needle, translocator, gate-keeper and effector. These interactions were further confirmed by Microscale Thermophoresis that also indicated a preferential interaction of PscN with secreted proteins or protein-chaperone complex rather than with chaperones alone, in line with the release of the chaperones in the bacterial cytoplasm after the dissociation from their exported proteins. Moreover, we suggest a new role of the gate-keeper complex and the ATPase in the regulation of early substrates recognition by the T3SS. This finding sheds a new light on the mechanism of secretion switching from early to middle substrates in P. aeruginosa.
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Affiliation(s)
- Tuan-Dung Ngo
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France
| | - Caroline Perdu
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France
| | - Bakhos Jneid
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France
| | - Michel Ragno
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France
| | | | - Alexandra Kraut
- Univ. Grenoble Alpes, CEA, INSERM, IRIG, BGE, 38000 Grenoble, France
| | - Yohann Couté
- Univ. Grenoble Alpes, CEA, INSERM, IRIG, BGE, 38000 Grenoble, France
| | - Charles Stopford
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ina Attrée
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France
| | - Arne Rietsch
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Eric Faudry
- Univ. Grenoble Alpes, CEA, INSERM, CNRS, Bacterial Pathogenesis and Cellular Responses, Interdisciplinary Research Institute of Grenoble, France.
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26
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Jensen JL, Yamini S, Rietsch A, Spiller BW. "The structure of the Type III secretion system export gate with CdsO, an ATPase lever arm". PLoS Pathog 2020; 16:e1008923. [PMID: 33048983 PMCID: PMC7584215 DOI: 10.1371/journal.ppat.1008923] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 10/23/2020] [Accepted: 08/24/2020] [Indexed: 01/10/2023] Open
Abstract
Type III protein secretion systems (T3SS) deliver effector proteins from the Gram-negative bacterial cytoplasm into a eukaryotic host cell through a syringe-like, multi-protein nanomachine. Cytosolic components of T3SS include a portion of the export apparatus, which traverses the inner membrane and features the opening of the secretion channel, and the sorting complex for substrate recognition and for providing the energetics required for protein secretion. Two components critical for efficient effector export are the export gate protein and the ATPase, which are proposed to be linked by the central stalk protein of the ATPase. We present the structure of the soluble export gate homo-nonamer, CdsV, in complex with the central stalk protein, CdsO, of its cognate ATPase, both derived from Chlamydia pneumoniae. This structure defines the interface between these essential T3S proteins and reveals that CdsO engages the periphery of the export gate that may allow the ATPase to catalyze an opening between export gate subunits to allow cargo to enter the export apparatus. We also demonstrate through structure-based mutagenesis of the homologous export gate in Pseudomonas aeruginosa that mutation of this interface disrupts effector secretion. These results provide novel insights into the molecular mechanisms governing active substrate recognition and translocation through a T3SS. Many pathogenic Gram-negative bacteria utilize T3SS to export virulence factors in a well-regulated manner. Most component proteins of the T3SS are highly structurally conserved, capable of recognizing and secreting diverse effectors, which are recruited to the cytoplasmic sorting complex by chaperones. This work describes the molecular architecture of two essential components of a T3SS, identifies the interface between the components, and establishes the necessity of this interaction for effector secretion.
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Affiliation(s)
- Jaime L. Jensen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Shavait Yamini
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States of America
| | - Arne Rietsch
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, United States of America
| | - Benjamin W. Spiller
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States of America
- * E-mail:
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27
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Zhuang X, Guo S, Li Z, Zhao Z, Kojima S, Homma M, Wang P, Lo C, Bai F. Live‐cell fluorescence imaging reveals dynamic production and loss of bacterial flagella. Mol Microbiol 2020; 114:279-291. [DOI: 10.1111/mmi.14511] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/10/2020] [Accepted: 03/30/2020] [Indexed: 02/02/2023]
Affiliation(s)
- Xiang‐Yu Zhuang
- Department of Physics and Graduate Institute of Biophysics National Central University Jhongli Taiwan, R.O.C
| | - Shihao Guo
- Biomedical Pioneering Innovation Center (BIOPIC) School of Life Sciences Peking University Beijing China
- Department of General Surgery Peking University First Hospital Peking University Beijing China
| | - Zhuoran Li
- Biomedical Pioneering Innovation Center (BIOPIC) School of Life Sciences Peking University Beijing China
| | - Ziyi Zhao
- Biomedical Pioneering Innovation Center (BIOPIC) School of Life Sciences Peking University Beijing China
| | - Seiji Kojima
- Division of Biological Science Graduate School of Science Nagoya University Nagoya Japan
| | - Michio Homma
- Division of Biological Science Graduate School of Science Nagoya University Nagoya Japan
| | - Pengyuan Wang
- Department of General Surgery Peking University First Hospital Peking University Beijing China
| | - Chien‐Jung Lo
- Department of Physics and Graduate Institute of Biophysics National Central University Jhongli Taiwan, R.O.C
| | - Fan Bai
- Biomedical Pioneering Innovation Center (BIOPIC) School of Life Sciences Peking University Beijing China
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Beeby M, Ferreira JL, Tripp P, Albers SV, Mitchell DR. Propulsive nanomachines: the convergent evolution of archaella, flagella and cilia. FEMS Microbiol Rev 2020; 44:253-304. [DOI: 10.1093/femsre/fuaa006] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
ABSTRACT
Echoing the repeated convergent evolution of flight and vision in large eukaryotes, propulsive swimming motility has evolved independently in microbes in each of the three domains of life. Filamentous appendages – archaella in Archaea, flagella in Bacteria and cilia in Eukaryotes – wave, whip or rotate to propel microbes, overcoming diffusion and enabling colonization of new environments. The implementations of the three propulsive nanomachines are distinct, however: archaella and flagella rotate, while cilia beat or wave; flagella and cilia assemble at their tips, while archaella assemble at their base; archaella and cilia use ATP for motility, while flagella use ion-motive force. These underlying differences reflect the tinkering required to evolve a molecular machine, in which pre-existing machines in the appropriate contexts were iteratively co-opted for new functions and whose origins are reflected in their resultant mechanisms. Contemporary homologies suggest that archaella evolved from a non-rotary pilus, flagella from a non-rotary appendage or secretion system, and cilia from a passive sensory structure. Here, we review the structure, assembly, mechanism and homologies of the three distinct solutions as a foundation to better understand how propulsive nanomachines evolved three times independently and to highlight principles of molecular evolution.
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Affiliation(s)
- Morgan Beeby
- Department of Life Sciences, Frankland Road, Imperial College of London, London, SW7 2AZ, UK
| | - Josie L Ferreira
- Department of Life Sciences, Frankland Road, Imperial College of London, London, SW7 2AZ, UK
| | - Patrick Tripp
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Schaenzlestrasse 1, 79211 Freiburg, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Schaenzlestrasse 1, 79211 Freiburg, Germany
| | - David R Mitchell
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA
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Drehkopf S, Otten C, Hausner J, Seifert T, Büttner D. HrpB7 from
Xanthomonas campestris
pv.
vesicatoria
is an essential component of the type III secretion system and shares features of HrpO/FliJ/YscO family members. Cell Microbiol 2020; 22:e13160. [DOI: 10.1111/cmi.13160] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/16/2019] [Accepted: 12/24/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Sabine Drehkopf
- Department of Genetics, Institute of BiologyMartin Luther University Halle‐Wittenberg Halle (Saale) Germany
| | - Christian Otten
- Department of Genetics, Institute of BiologyMartin Luther University Halle‐Wittenberg Halle (Saale) Germany
| | - Jens Hausner
- Department of Genetics, Institute of BiologyMartin Luther University Halle‐Wittenberg Halle (Saale) Germany
| | - Tanja Seifert
- Department of Genetics, Institute of BiologyMartin Luther University Halle‐Wittenberg Halle (Saale) Germany
| | - Daniela Büttner
- Department of Genetics, Institute of BiologyMartin Luther University Halle‐Wittenberg Halle (Saale) Germany
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Abstract
Periplasmic flagella are complex nanomachines responsible for distinctive morphology and motility of spirochetes. Although bacterial flagella have been extensively studied for several decades in the model systems Escherichia coli and Salmonella enterica, our understanding of periplasmic flagella in many disease-causing spirochetes remains incomplete. Recent advances, including molecular genetics, biochemistry, structural biology, and cryo-electron tomography, have greatly increased our understanding of structure and function of periplasmic flagella. In this chapter, we summarize some of the recent findings that provide new insights into the structure, assembly, and function of periplasmic flagella.
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In Vitro Autonomous Construction of the Flagellar Axial Structure in Inverted Membrane Vesicles. Biomolecules 2020; 10:biom10010126. [PMID: 31940802 PMCID: PMC7022808 DOI: 10.3390/biom10010126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 02/07/2023] Open
Abstract
The bacterial flagellum is a filamentous organelle extending from the cell surface. The axial structure of the flagellum consists of the rod, hook, junction, filament, and cap. The axial structure is formed by axial component proteins exported via a specific protein export apparatus in a well-regulated manner. Although previous studies have revealed the outline of the flagellar construction process, the mechanism of axial structure formation, including axial protein export, is still obscure due to difficulties in direct observation of protein export and assembly in vivo. We recently developed an in vitro flagellar protein transport assay system using inverted membrane vesicles (IMVs) and succeeded in reproducing the early stage of flagellar assembly. However, the late stage of the flagellar formation process remained to be examined in the IMVs. In this study, we showed that the filament-type proteins are transported into the IMVs to produce the filament on the hook inside the IMVs. Furthermore, we provide direct evidence that coordinated flagellar protein export and assembly can occur at the post-translational level. These results indicate that the ordered construction of the entire flagellar structure can be regulated by only the interactions between the protein export apparatus, the export substrate proteins, and their cognate chaperones.
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Henderson LD, Matthews-Palmer TRS, Gulbronson CJ, Ribardo DA, Beeby M, Hendrixson DR. Diversification of Campylobacter jejuni Flagellar C-Ring Composition Impacts Its Structure and Function in Motility, Flagellar Assembly, and Cellular Processes. mBio 2020; 11:e02286-19. [PMID: 31911488 PMCID: PMC6946799 DOI: 10.1128/mbio.02286-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/19/2019] [Indexed: 12/22/2022] Open
Abstract
Bacterial flagella are reversible rotary motors that rotate external filaments for bacterial propulsion. Some flagellar motors have diversified by recruiting additional components that influence torque and rotation, but little is known about the possible diversification and evolution of core motor components. The mechanistic core of flagella is the cytoplasmic C ring, which functions as a rotor, directional switch, and assembly platform for the flagellar type III secretion system (fT3SS) ATPase. The C ring is composed of a ring of FliG proteins and a helical ring of surface presentation of antigen (SPOA) domains from the switch proteins FliM and one of two usually mutually exclusive paralogs, FliN or FliY. We investigated the composition, architecture, and function of the C ring of Campylobacter jejuni, which encodes FliG, FliM, and both FliY and FliN by a variety of interrogative approaches. We discovered a diversified C. jejuni C ring containing FliG, FliM, and both FliY, which functions as a classical FliN-like protein for flagellar assembly, and FliN, which has neofunctionalized into a structural role. Specific protein interactions drive the formation of a more complex heterooligomeric C. jejuni C-ring structure. We discovered that this complex C ring has additional cellular functions in polarly localizing FlhG for numerical regulation of flagellar biogenesis and spatial regulation of division. Furthermore, mutation of the C. jejuni C ring revealed a T3SS that was less dependent on its ATPase complex for assembly than were other systems. Our results highlight considerable evolved flagellar diversity that impacts motor output, biogenesis, and cellular processes in different species.IMPORTANCE The conserved core of bacterial flagellar motors reflects a shared evolutionary history that preserves the mechanisms essential for flagellar assembly, rotation, and directional switching. In this work, we describe an expanded and diversified set of core components in the Campylobacter jejuni flagellar C ring, the mechanistic core of the motor. Our work provides insight into how usually conserved core components may have diversified by gene duplication, enabling a division of labor of the ancestral protein between the two new proteins, acquisition of new roles in flagellar assembly and motility, and expansion of the function of the flagellum beyond motility, including spatial regulation of cell division and numerical control of flagellar biogenesis in C. jejuni Our results highlight that relatively small changes, such as gene duplications, can have substantial ramifications on the cellular roles of a molecular machine.
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Affiliation(s)
- Louie D Henderson
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Connor J Gulbronson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Deborah A Ribardo
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - David R Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Singh N, Wagner S. Investigating the assembly of the bacterial type III secretion system injectisome by in vivo photocrosslinking. Int J Med Microbiol 2019; 309:151331. [DOI: 10.1016/j.ijmm.2019.151331] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 07/09/2019] [Accepted: 07/12/2019] [Indexed: 12/11/2022] Open
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34
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Lyons BJE, Strynadka NCJ. On the road to structure-based development of anti-virulence therapeutics targeting the type III secretion system injectisome. MEDCHEMCOMM 2019; 10:1273-1289. [PMID: 31534650 PMCID: PMC6748289 DOI: 10.1039/c9md00146h] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/07/2019] [Indexed: 12/19/2022]
Abstract
The type III secretion system injectisome is a syringe-like multimembrane spanning nanomachine that is essential to the pathogenicity but not viability of many clinically relevant Gram-negative bacteria, such as enteropathogenic Escherichia coli, Salmonella enterica and Pseudomonas aeruginosa. Due to the rise in antibiotic resistance, new strategies must be developed to treat the growing spectre of drug resistant infections. Targeting the injectisome via an 'anti-virulence strategy' is a promising avenue to pursue as an alternative to the more commonly used bactericidal therapeutics, which have a high propensity for resulting resistance development and often more broad killing profile, including unwanted side effects in eliminating favourable members of the microbiome. Building on more than a decade of crystallographic work of truncated or isolated forms of the more than two dozen components of the secretion apparatus, recent advances in the field of single-particle cryo-electron microscopy have allowed for the elucidation of atomic resolution structures for many of the type III secretion system components in their assembled, oligomerized state including the needle complex, export apparatus and ATPase. Cryo-electron tomography studies have also advanced our understanding of the direct pathogen-host interaction between the type III secretion system translocon and host cell membrane. These new structural works that further our understanding of the myriad of protein-protein interactions that promote injectisome function will be highlighted in this review, with a focus on those that yield promise for future anti-virulence drug discovery and design. Recently developed inhibitors, including both synthetic, natural product and peptide inhibitors, as well as promising new developments of immunotherapeutics will be discussed. As our understanding of this intricate molecular machinery advances, the development of anti-virulence inhibitors can be enhanced through structure-guided drug design.
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Affiliation(s)
- Bronwyn J E Lyons
- Department of Biochemistry and Molecular Biology and Center for Blood Research , University of British Columbia , 2350 Health Sciences Mall , Vancouver , British Columbia V6T 1Z3 , Canada .
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and Center for Blood Research , University of British Columbia , 2350 Health Sciences Mall , Vancouver , British Columbia V6T 1Z3 , Canada .
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35
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Flagella-Driven Motility of Bacteria. Biomolecules 2019; 9:biom9070279. [PMID: 31337100 PMCID: PMC6680979 DOI: 10.3390/biom9070279] [Citation(s) in RCA: 181] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 01/17/2023] Open
Abstract
The bacterial flagellum is a helical filamentous organelle responsible for motility. In bacterial species possessing flagella at the cell exterior, the long helical flagellar filament acts as a molecular screw to generate thrust. Meanwhile, the flagella of spirochetes reside within the periplasmic space and not only act as a cytoskeleton to determine the helicity of the cell body, but also rotate or undulate the helical cell body for propulsion. Despite structural diversity of the flagella among bacterial species, flagellated bacteria share a common rotary nanomachine, namely the flagellar motor, which is located at the base of the filament. The flagellar motor is composed of a rotor ring complex and multiple transmembrane stator units and converts the ion flux through an ion channel of each stator unit into the mechanical work required for motor rotation. Intracellular chemotactic signaling pathways regulate the direction of flagella-driven motility in response to changes in the environments, allowing bacteria to migrate towards more desirable environments for their survival. Recent experimental and theoretical studies have been deepening our understanding of the molecular mechanisms of the flagellar motor. In this review article, we describe the current understanding of the structure and dynamics of the bacterial flagellum.
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36
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Slater SL, Sågfors AM, Pollard DJ, Ruano-Gallego D, Frankel G. The Type III Secretion System of Pathogenic Escherichia coli. Curr Top Microbiol Immunol 2019; 416:51-72. [PMID: 30088147 DOI: 10.1007/82_2018_116] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Infection with enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC), enteroinvasive E. coli (EIEC) and Shigella relies on the elaboration of a type III secretion system (T3SS). Few strains also encode a second T3SS, named ETT2. Through the integration of coordinated intracellular and extracellular cues, the modular T3SS is assembled within the bacterial cell wall, as well as the plasma membrane of the host cell. As such, the T3SS serves as a conduit, allowing the chaperone-regulated translocation of effector proteins directly into the host cytosol to subvert eukaryotic cell processes. Recent technological advances revealed high structural resolution of the T3SS apparatus and how it could be exploited to treat enteric disease. This chapter summarises the current knowledge of the structure and function of the E. coli T3SSs.
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Affiliation(s)
- Sabrina L Slater
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Agnes M Sågfors
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Dominic J Pollard
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - David Ruano-Gallego
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Gad Frankel
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK.
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37
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Inoue Y, Ogawa Y, Kinoshita M, Terahara N, Shimada M, Kodera N, Ando T, Namba K, Kitao A, Imada K, Minamino T. Structural Insights into the Substrate Specificity Switch Mechanism of the Type III Protein Export Apparatus. Structure 2019; 27:965-976.e6. [PMID: 31031200 DOI: 10.1016/j.str.2019.03.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/16/2019] [Accepted: 03/22/2019] [Indexed: 12/22/2022]
Abstract
Bacteria use a type III protein export apparatus for construction of the flagellum, which consists of the basal body, the hook, and the filament. FlhA forms a homo-nonamer through its C-terminal cytoplasmic domains (FlhAC) and ensures the strict order of flagellar assembly. FlhAC goes through dynamic domain motions during protein export, but it remains unknown how it occurs. Here, we report that the FlhA(G368C) mutation biases FlhAC toward a closed form, thereby reducing the binding affinity of FlhAC for flagellar export chaperones in complex with their cognate filament-type substrates. The G368C mutations also restrict the conformational flexibility of a linker region of FlhA (FlhAL), suppressing FlhAC ring formation. We propose that interactions of FlhAL with its neighboring subunit converts FlhAC in the ring from a closed conformation to an open one, allowing the chaperon/substrate complexes to bind to the FlhAC ring to form the filament at the hook tip.
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Affiliation(s)
- Yumi Inoue
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yuya Ogawa
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Naoya Terahara
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Masafumi Shimada
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Noriyuki Kodera
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Toshio Ando
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan; RIKEN Center for Biosystems Dynamics Research & SPring-8 Center, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Akio Kitao
- School of Life Science and Technology, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8550, Japan.
| | - Katsumi Imada
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan.
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.
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38
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Majewski DD, Worrall LJ, Hong C, Atkinson CE, Vuckovic M, Watanabe N, Yu Z, Strynadka NCJ. Cryo-EM structure of the homohexameric T3SS ATPase-central stalk complex reveals rotary ATPase-like asymmetry. Nat Commun 2019; 10:626. [PMID: 30733444 PMCID: PMC6367419 DOI: 10.1038/s41467-019-08477-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 01/11/2019] [Indexed: 12/31/2022] Open
Abstract
Many Gram-negative bacteria, including causative agents of dysentery, plague, and typhoid fever, rely on a type III secretion system - a multi-membrane spanning syringe-like apparatus - for their pathogenicity. The cytosolic ATPase complex of this injectisome is proposed to play an important role in energizing secretion events and substrate recognition. We present the 3.3 Å resolution cryo-EM structure of the enteropathogenic Escherichia coli ATPase EscN in complex with its central stalk EscO. The structure shows an asymmetric pore with different functional states captured in its six catalytic sites, details directly supporting a rotary catalytic mechanism analogous to that of the heterohexameric F1/V1-ATPases despite its homohexameric nature. Situated at the C-terminal opening of the EscN pore is one molecule of EscO, with primary interaction mediated through an electrostatic interface. The EscN-EscO structure provides significant atomic insights into how the ATPase contributes to type III secretion, including torque generation and binding of chaperone/substrate complexes.
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Affiliation(s)
- Dorothy D Majewski
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - Liam J Worrall
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, BC, Canada
- HRMEM Facility, University of British Columbia, Vancouver, BC, Canada
| | - Chuan Hong
- CryoEM Shared Resources, Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA
- Merck & Co., Department of Biochemical Engineering and Structure, 2000 Galloping Hill Road, Kenilworth, NJ, 07033, USA
| | - Claire E Atkinson
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, BC, Canada
- HRMEM Facility, University of British Columbia, Vancouver, BC, Canada
| | - Marija Vuckovic
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - Nobuhiko Watanabe
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - Zhiheng Yu
- CryoEM Shared Resources, Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, USA.
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, BC, Canada.
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39
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Diepold A. Assembly and Post-assembly Turnover and Dynamics in the Type III Secretion System. Curr Top Microbiol Immunol 2019; 427:35-66. [PMID: 31218503 DOI: 10.1007/82_2019_164] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The type III secretion system (T3SS) is one of the largest transmembrane complexes in bacteria, comprising several intricately linked and embedded substructures. The assembly of this nanomachine is a hierarchical process which is regulated and controlled by internal and external cues at several critical points. Recently, it has become obvious that the assembly of the T3SS is not a unidirectional and deterministic process, but that parts of the T3SS constantly exchange or rearrange. This article aims to give an overview on the assembly and post-assembly dynamics of the T3SS, with a focus on emerging general concepts and adaptations of the general assembly pathway.
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Affiliation(s)
- Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, 35043, Marburg, Germany.
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40
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41
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Molecular Organization and Assembly of the Export Apparatus of Flagellar Type III Secretion Systems. Curr Top Microbiol Immunol 2019; 427:91-107. [PMID: 31172377 DOI: 10.1007/82_2019_170] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The bacterial flagellum is a supramolecular motility machine consisting of the basal body, the hook, and the filament. For construction of the flagellum beyond the cellular membranes, a type III protein export apparatus uses ATP and proton-motive force (PMF) across the cytoplasmic membrane as the energy sources to transport flagellar component proteins from the cytoplasm to the distal end of the growing flagellar structure. The protein export apparatus consists of a PMF-driven transmembrane export gate complex and a cytoplasmic ATPase complex. In addition, the basal body C ring acts as a sorting platform for the cytoplasmic ATPase complex that efficiently brings export substrates and type III export chaperone-substrate complexes from the cytoplasm to the export gate complex. In this book chapter, we will summarize our current understanding of molecular organization and assembly of the flagellar type III protein export apparatus.
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Export Mechanisms and Energy Transduction in Type-III Secretion Machines. Curr Top Microbiol Immunol 2019; 427:143-159. [PMID: 31218506 DOI: 10.1007/82_2019_166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The remarkably complex architecture and organization of bacterial nanomachines originally raised the enigma to how they are assembled in a coordinated manner. Over the years, the assembly processes of the flagellum and evolutionary-related injectisome complexes have been deciphered and were shown to rely on a conserved protein secretion machine: the type-III secretion system. In this book chapter, we demonstrate how individually evolved mechanisms cooperate in highly versatile and robust secretion machinery to export and assemble the building blocks of those nanomachines.
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43
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Halder PK, Roy C, Datta S. Structural and functional characterization of type three secretion system ATPase PscN and its regulator PscL from Pseudomonas aeruginosa. Proteins 2018; 87:276-288. [PMID: 30561072 DOI: 10.1002/prot.25648] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 10/29/2018] [Accepted: 12/12/2018] [Indexed: 12/16/2022]
Affiliation(s)
- Pranab Kumar Halder
- Structural Biology and Bioinformatics Division; Council of Scientific and Industrial Research-Indian Institute of Chemical Biology; Kolkata West Bengal India
| | - Chittran Roy
- Structural Biology and Bioinformatics Division; Council of Scientific and Industrial Research-Indian Institute of Chemical Biology; Kolkata West Bengal India
| | - Saumen Datta
- Structural Biology and Bioinformatics Division; Council of Scientific and Industrial Research-Indian Institute of Chemical Biology; Kolkata West Bengal India
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44
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Cryo-electron tomography of periplasmic flagella in Borrelia burgdorferi reveals a distinct cytoplasmic ATPase complex. PLoS Biol 2018; 16:e3000050. [PMID: 30412577 PMCID: PMC6248999 DOI: 10.1371/journal.pbio.3000050] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 11/21/2018] [Accepted: 10/23/2018] [Indexed: 12/25/2022] Open
Abstract
Periplasmic flagella are essential for the distinct morphology and motility of spirochetes. A flagella-specific type III secretion system (fT3SS) composed of a membrane-bound export apparatus and a cytosolic ATPase complex is responsible for the assembly of the periplasmic flagella. Here, we deployed cryo-electron tomography (cryo-ET) to visualize the fT3SS machine in the Lyme disease spirochete Borrelia burgdorferi. We show, for the first time, that the cytosolic ATPase complex is attached to the flagellar C-ring through multiple spokes to form the “spoke and hub” structure in B. burgdorferi. This structure not only strengthens structural rigidity of the round-shaped C-ring but also appears to rotate with the C-ring. Our studies provide structural insights into the unique mechanisms underlying assembly and rotation of the periplasmic flagella and may provide the basis for the development of novel therapeutic strategies against several pathogenic spirochetes. Cryo-electron tomography of periplasmic flagella in the Lyme disease bacterium Borrelia burgdorferi reveals it to have a distinct cytoplasmic ATPase complex and an atypical interaction with the flagellar C-ring. Type III secretion systems are widely utilized by gram-negative bacteria to assemble flagella or to transport virulence effectors into eukaryotic cells. The central component is known as a type III secretion machine, which consists of a membrane-bound export apparatus and a cytosolic ATPase complex. Powered by the proton motive force and ATP hydrolysis, the secretion machine is responsible for substrate recognition and export. Here, we use the Lyme disease spirochete B. burgdorferi as a model system to unveil unprecedented structural details of the intact flagellar secretion machine by high-throughput cryo-electron tomography (cryo-ET) and subtomogram averaging. We provide the first structural evidence that the cytosolic ATPase complex is attached to the flagellar C-ring through multiple spokes to form the “spoke and hub” structure in B. burgdorferi. The novel architecture of the ATPase complex not only strengthens the flagellar C-ring but also enables an optimal translocation of substrates through the ATPase complex and the export apparatus.
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Hemalatha CR, Abhinand PA, Iyer M, Paul BC, Jyoti Kindo A, Ravinder T, P D. Phytochemical derivatives targeting fliJ flagellar protein from Escherichia coli. Bioinformation 2018; 14:465-470. [PMID: 31223204 PMCID: PMC6563656 DOI: 10.6026/97320630014465] [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: 09/25/2018] [Revised: 10/03/2018] [Accepted: 10/05/2018] [Indexed: 11/23/2022] Open
Abstract
Approximately 50 per cent of nosocomial infections are caused by the use of indwelling medical devices. The surfaces of devices are ideal sites of attachment for bacterial cells and an increase in biofilm formation. Biofilms have been a constant concern due to their complex extracellular matrix (ECM) resulting in multiple drug resistance. E. coli is known to associate with biofilms. Therefore it is of interest to identify the proteins associated to biofilm formation in Escherichia coli through literature survey, investigate their protein-protein interactions and identify indispensible proteins of biofilm formation. These proteins were further analyzed and fliJ was identified as the target, based on betweenness, centrality and radiality. 87 phytochemicals were found to be associated with the microbe in question and were docked with the target using Molegro Virtual Docker (MVD) 5.0. The results showed that geranyl pyrophosphate, ferulic acid 4-o-b-d-glucuronide, 5-8'-dehydrodiferulic acid and geranyl diphosphate showed maximum activity. A combinatorial library of 96 models was generated using the four phytochemicals binding with fliJ.
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Affiliation(s)
- CR Hemalatha
- Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai – 600116
| | - PA Abhinand
- Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai – 600116
| | - Maithreyi Iyer
- Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai – 600116
| | - Benedict C Paul
- Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai – 600116
| | - Anupma Jyoti Kindo
- Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai – 600116
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46
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Wagner S, Grin I, Malmsheimer S, Singh N, Torres-Vargas CE, Westerhausen S. Bacterial type III secretion systems: a complex device for the delivery of bacterial effector proteins into eukaryotic host cells. FEMS Microbiol Lett 2018; 365:5068689. [PMID: 30107569 PMCID: PMC6140923 DOI: 10.1093/femsle/fny201] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/08/2018] [Indexed: 12/21/2022] Open
Abstract
Virulence-associated type III secretion systems (T3SS) serve the injection of bacterial effector proteins into eukaryotic host cells. They are able to secrete a great diversity of substrate proteins in order to modulate host cell function, and have evolved to sense host cell contact and to inject their substrates through a translocon pore in the host cell membrane. T3SS substrates contain an N-terminal signal sequence and often a chaperone-binding domain for cognate T3SS chaperones. These signals guide the substrates to the machine where substrates are unfolded and handed over to the secretion channel formed by the transmembrane domains of the export apparatus components and by the needle filament. Secretion itself is driven by the proton motive force across the bacterial inner membrane. The needle filament measures 20-150 nm in length and is crowned by a needle tip that mediates host-cell sensing. Secretion through T3SS is a highly regulated process with early, intermediate and late substrates. A strict secretion hierarchy is required to build an injectisome capable of reaching, sensing and penetrating the host cell membrane, before host cell-acting effector proteins are deployed. Here, we review the recent progress on elucidating the assembly, structure and function of T3SS injectisomes.
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Affiliation(s)
- Samuel Wagner
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
- German Center for Infection Research (DZIF), partner-site Tübingen, Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
| | - Iwan Grin
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
| | - Silke Malmsheimer
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
| | - Nidhi Singh
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
| | - Claudia E Torres-Vargas
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
| | - Sibel Westerhausen
- University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Elfriede-Aulhorn-Str. 6, 72076 Tübingen, Germany
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Terashima H, Imada K. Novel insight into an energy transduction mechanism of the bacterial flagellar type III protein export. Biophys Physicobiol 2018; 15:173-178. [PMID: 30250776 PMCID: PMC6145943 DOI: 10.2142/biophysico.15.0_173] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 07/20/2018] [Indexed: 01/05/2023] Open
Abstract
Type III secretion system (T3SS) is a protein translocator complex family including pathogenic injectisome or bacterial flagellum. The inejectisomal T3SS serves to deliver virulence proteins into host cell and the flagellar T3SS constructs the flagellar axial structure. Although earlier studies have provided many findings on the molecular mechanism of the Type III protein export, they were not sufficient to reveal energy transduction mechanism due to difficulties in controlling measurement conditions in vivo. Recently, we developed an in vitro flagellar Type III protein transport assay system using inverted membrane vesicles (IMVs), and analyzed protein export by using the in vitro method. We reproduced protein export of the flagellar T3SS, hook assembly and substrate specificity switch in IMV to a similar extent to what is seen in living cell. Furthermore, we demonstrated that ATP-hydrolysis energy can drive protein transport even in the absence of proton-motive force (PMF). In this mini-review, we will summarize our new in vitro Type III transport assay method and our findings on the molecular mechanism of Type III protein export.
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Affiliation(s)
- Hiroyuki Terashima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Katsumi Imada
- Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
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Berrocoso JD, Kida R, Singh AK, Kim YS, Jha R. Effect of in ovo injection of raffinose on growth performance and gut health parameters of broiler chicken. Poult Sci 2018; 96:1573-1580. [PMID: 27920191 DOI: 10.3382/ps/pew430] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 10/26/2016] [Indexed: 12/13/2022] Open
Abstract
The effects of in ovo injection of raffinose (RFO) as a prebiotic on growth performance, relative weight of proventriculus, gizzard, drumstick and breast muscles, and ileum mucosa morphology were examined in Cobb 500 broilers. A total of 240 fertilized eggs were divided into 4 groups: a non-injected with intact shell and 3 levels of RFO solution (1.5, 3.0, and 4.5 mg in 0.2 mL of an aqueous diluents). The RFO solution was injected into the air sac on d 12 of incubation. In total 144 birds were fed a standard diet and management and sacrificed at d 21 post hatch for collection of samples. Total RNA was extracted from the small intestine, and RT-qPCR was performed to quantify mRNA levels of marker genes of immune cells. Injection of RFO had no significant effect (P > 0.05) on d one body weight of chicks. On d 21, the relative weight of the proventriculus, drumstick, breast, and gizzard was not affected (P > 0.05) by RFO. On hatch d, the villus height increased linearly (P < 0.01) with an increasing dose of RFO. Also, an increasing dose of RFO increased the villus height and villus height:crypt depth ratio (P < 0.05) but did not affect the crypt depth on d 21. The expression levels of CD3 and chB6, which are T cell and B cell marker genes, respectively, were significantly enhanced by high dose RFO (4.5 mg). In conclusion, although an increasing dose of RFO in ovo injection did not significantly influence growth performance or slaughter yield of broilers, RFO has the potential of enhancing ileum mucosa morphology and improving immunity in the small intestine, which are indicators of improved gut health.
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In Vitro
Reconstitution of Functional Type III Protein Export and Insights into Flagellar Assembly. mBio 2018; 9:mBio.00988-18. [PMID: 29946050 PMCID: PMC6020293 DOI: 10.1128/mbio.00988-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
ABSTRACT
The type III secretion system (T3SS) forms the functional core of injectisomes, protein transporters that allow bacteria to deliver virulence factors into their hosts for infection, and flagella, which are critical for many pathogens to reach the site of infection. In spite of intensive genetic and biochemical studies, the T3SS protein export mechanism remains unclear due to the difficulty of accurate measurement of protein export
in vivo
. Here, we developed an
in vitro
flagellar T3S protein transport assay system using an inverted cytoplasmic membrane vesicle (IMV) for accurate and controlled measurements of flagellar protein export. We show that the flagellar T3SS in the IMV fully retains export activity. The flagellar hook was constructed inside the lumen of the IMV by adding purified component proteins externally to the IMV solution. We reproduced the hook length control and export specificity switch in the IMV consistent with that seen in the native cell. Previous
in vivo
analyses showed that flagellar protein export is driven by proton motive force (PMF) and facilitated by ATP hydrolysis by FliI, a T3SS-specific ATPase. Our
in vitro
assay recapitulated these previous
in vivo
observations but furthermore clearly demonstrated that even ATP hydrolysis by FliI alone can drive flagellar protein export. Moreover, this assay showed that addition of the FliH
2
/FliI complex to the assay solution at a concentration similar to that in the cell dramatically enhanced protein export, confirming that the FliH
2
/FliI complex in the cytoplasm is important for effective protein transport.
IMPORTANCE
The type III secretion system (T3SS) is the functional core of the injectisome, a bacterial protein transporter used to deliver virulence proteins into host cells, and bacterial flagella, critical for many pathogens. The molecular mechanism of protein transport is still unclear due to difficulties in accurate measurements of protein transport under well-controlled conditions
in vivo
. We succeeded in developing an
in vitro
transport assay system of the flagellar T3SS using inverted membrane vesicles (IMVs). Flagellar hook formation was reproduced in the IMV, suggesting that the export apparatus in the IMV retains a protein transport activity similar to that in the cell. Using this system, we revealed that ATP hydrolysis by the T3SS ATPase can drive protein export without PMF.
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50
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Gao X, Mu Z, Yu X, Qin B, Wojdyla J, Wang M, Cui S. Structural Insight Into Conformational Changes Induced by ATP Binding in a Type III Secretion-Associated ATPase From Shigella flexneri. Front Microbiol 2018; 9:1468. [PMID: 30013545 PMCID: PMC6036117 DOI: 10.3389/fmicb.2018.01468] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 06/12/2018] [Indexed: 11/13/2022] Open
Abstract
Gram-negative bacteria utilize the type III secretion system (T3SS) to inject effector proteins into the host cell cytoplasm, where they subvert cellular functions and assist pathogen invasion. The conserved type III-associated ATPase is critical for the separation of chaperones from effector proteins, the unfolding of effector proteins and translocating them through the narrow channel of the secretion apparatus. However, how ATP hydrolysis is coupled to the mechanical work of the enzyme remains elusive. Herein, we present a complete description of nucleoside triphosphate binding by surface presentation antigens 47 (Spa47) from Shigella flexneri, based on crystal structures containing ATPγS, a catalytic magnesium ion and an ordered water molecule. Combining the crystal structures of Spa47-ATPγS and unliganded Spa47, we propose conformational changes in Spa47 associated with ATP binding, the binding of ATP induces a conformational change of a highly conserved luminal loop, facilitating ATP hydrolysis by the Spa47 ATPase. Additionally, we identified a specific hydrogen bond critical for ATP recognition and demonstrated that, while ATPγS is an ideal analog for probing ATP binding, AMPPNP is a poor ATP mimic. Our findings provide structural insight pertinent for inhibitor design.
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Affiliation(s)
- Xiaopan Gao
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhixia Mu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xia Yu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Bo Qin
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Justyna Wojdyla
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Meitian Wang
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Sheng Cui
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
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