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Verma RK, Gondu P, Saha T, Chatterjee S. The Global Transcription Regulator XooClp Governs Type IV Pili System-Mediated Bacterial Virulence by Directly Binding to TFP-Chp Promoters to Coordinate Virulence Associated Functions. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:357-369. [PMID: 38105438 DOI: 10.1094/mpmi-07-23-0100-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Type IV pili (TFP) play a crucial role in the sensing of the external environment for several bacteria. This surface sensing is essential for the lifestyle transitions of several bacteria and involvement in pathogenesis. However, the precise mechanisms underlying TFP's integration of environmental cues, particularly in regulating the TFP-Chp system and its effects on Xanthomonas physiology, social behavior, and virulence, remain poorly understood. In this study, we focused on investigating Clp, a global transcriptional regulator similar to CRP-like proteins, in Xanthomonas oryzae pv. oryzae, a plant pathogen. Our findings reveal that Clp integrates environmental cues detected through diffusible signaling factor (DSF) quorum sensing into the TFP-Chp regulatory system. It accomplishes this by directly binding to TFP-Chp promoters in conjunction with intracellular levels of cyclic-di-GMP, a ubiquitous bacterial second messenger, thereby controlling TFP expression. Moreover, Clp-mediated regulation is involved in regulating several cellular processes, including the production of virulence-associated functions. Collectively, these processes contribute to host colonization and disease initiation. Our study elucidates the intricate regulatory network encompassing Clp, environmental cues, and the TFP-Chp system, providing insights into the molecular mechanisms that drive bacterial virulence in Xanthomonas spp. These findings offer valuable knowledge regarding Xanthomonas pathogenicity and present new avenues for innovative strategies aimed at combating plant diseases caused by these bacteria. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Raj Kumar Verma
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India
| | - Parimala Gondu
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India
| | - Tirthankar Saha
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India
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Little JI, Singh PK, Zhao J, Dunn S, Matz H, Donnenberg MS. Type IV pili of Enterobacteriaceae species. EcoSal Plus 2024:eesp00032023. [PMID: 38294234 DOI: 10.1128/ecosalplus.esp-0003-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 12/01/2023] [Indexed: 02/01/2024]
Abstract
Type IV pili (T4Ps) are surface filaments widely distributed among bacteria and archaea. T4Ps are involved in many cellular functions and contribute to virulence in some species of bacteria. Due to the diversity of T4Ps, different properties have been observed for homologous proteins that make up T4Ps in various organisms. In this review, we highlight the essential components of T4Ps, their functions, and similarities to related systems. We emphasize the unique T4Ps of enteric pathogens within the Enterobacteriaceae family, which includes pathogenic strains of Escherichia coli and Salmonella. These include the bundle-forming pilus (BFP) of enteropathogenic E. coli (EPEC), longus (Lng) and colonization factor III (CFA/III) of enterotoxigenic E. coli (ETEC), T4P of Salmonella enterica serovar Typhi, Colonization Factor Citrobacter (CFC) of Citrobacter rodentium, T4P of Yersinia pseudotuberculosis, a ubiquitous T4P that was characterized in enterohemorrhagic E. coli (EHEC), and the R64 plasmid thin pilus. Finally, we highlight areas for further study.
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Affiliation(s)
- Janay I Little
- School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Pradip K Singh
- School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Jinlei Zhao
- School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Shakeera Dunn
- Internal Medicine Residency, Bayhealth Medical Center, Dover, Delaware, USA
| | - Hanover Matz
- Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
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Guilvout I, Samsudin F, Huber RG, Bond PJ, Bardiaux B, Francetic O. Membrane platform protein PulF of the Klebsiella type II secretion system forms a trimeric ion channel essential for endopilus assembly and protein secretion. mBio 2024; 15:e0142323. [PMID: 38063437 PMCID: PMC10790770 DOI: 10.1128/mbio.01423-23] [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: 06/05/2023] [Accepted: 10/24/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE Type IV pili and type II secretion systems are members of the widespread type IV filament (T4F) superfamily of nanomachines that assemble dynamic and versatile surface fibers in archaea and bacteria. The assembly and retraction of T4 filaments with diverse surface properties and functions require the plasma membrane platform proteins of the GspF/PilC superfamily. Generally considered dimeric, platform proteins are thought to function as passive transmitters of the mechanical energy generated by the ATPase motor, to somehow promote insertion of pilin subunits into the nascent pilus fibers. Here, we generate and experimentally validate structural predictions that support the trimeric state of a platform protein PulF from a type II secretion system. The PulF trimers form selective proton or sodium channels which might energize pilus assembly using the membrane potential. The conservation of the channel sequence and structural features implies a common mechanism for all T4F assembly systems. We propose a model of the oligomeric PulF-PulE ATPase complex that provides an essential framework to investigate and understand the pilus assembly mechanism.
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Affiliation(s)
- Ingrid Guilvout
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Biochemistry of Macromolecular Interactions Unit, Paris, France
| | | | | | - Peter J. Bond
- Bioinformatics Institute (A-STAR), Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Benjamin Bardiaux
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Structural Bioinformatics Unit, Paris, France
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Bacterial Transmembrane Systems Unit, Paris, France
| | - Olivera Francetic
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Biochemistry of Macromolecular Interactions Unit, Paris, France
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Pelicic V. Mechanism of assembly of type 4 filaments: everything you always wanted to know (but were afraid to ask). MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 36947586 DOI: 10.1099/mic.0.001311] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Type 4 filaments (T4F) are a superfamily of filamentous nanomachines - virtually ubiquitous in prokaryotes and functionally versatile - of which type 4 pili (T4P) are the defining member. T4F are polymers of type 4 pilins, assembled by conserved multi-protein machineries. They have long been an important topic for research because they are key virulence factors in numerous bacterial pathogens. Our poor understanding of the molecular mechanisms of T4F assembly is a serious hindrance to the design of anti-T4F therapeutics. This review attempts to shed light on the fundamental mechanistic principles at play in T4F assembly by focusing on similarities rather than differences between several (mostly bacterial) T4F. This holistic approach, complemented by the revolutionary ability of artificial intelligence to predict protein structures, led to an intriguing mechanistic model of T4F assembly.
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Affiliation(s)
- Vladimir Pelicic
- Laboratoire de Chimie Bactérienne, UMR 7283 CNRS/Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, Marseille, France
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5
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Abstract
Type IV pili (T4P) are retractable multifunctional nanofibers present on the surface of numerous bacterial and archaeal species. Their importance to microbiology is difficult to overstate. The scientific journey leading to our current understanding of T4P structure and function has included many innovative research milestones. Although multiple T4P reviews over the years have emphasized recent advances, we find that current reports often omit many of the landmark discoveries in this field. Here, we attempt to highlight chronologically the most important work on T4P, from the discovery of pili to the application of sophisticated contemporary methods, which has brought us to our current state of knowledge. As there remains much to learn about the complex machine that assembles and retracts T4P, we hope that this review will increase the interest of current researchers and inspire innovative progress.
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Naskar S, Hohl M, Tassinari M, Low HH. The structure and mechanism of the bacterial type II secretion system. Mol Microbiol 2020; 115:412-424. [PMID: 33283907 DOI: 10.1111/mmi.14664] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/03/2020] [Indexed: 12/17/2022]
Abstract
The type II secretion system (T2SS) is a multi-protein complex used by many bacteria to move substrates across their cell membrane. Substrates released into the environment serve as local and long-range effectors that promote nutrient acquisition, biofilm formation, and pathogenicity. In both animals and plants, the T2SS is increasingly recognized as a key driver of virulence. The T2SS spans the bacterial cell envelope and extrudes substrates through an outer membrane secretin channel using a pseudopilus. An inner membrane assembly platform and a cytoplasmic motor controls pseudopilus assembly. This microreview focuses on the structure and mechanism of the T2SS. Advances in cryo-electron microscopy are enabling increasingly elaborate sub-complexes to be resolved. However, key questions remain regarding the mechanism of pseudopilus extension and retraction, and how this is coupled with the choreography of the substrate moving through the secretion system. The T2SS is part of an ancient type IV filament superfamily that may have been present within the last universal common ancestor (LUCA). Overall, mechanistic principles that underlie T2SS function have implication for other closely related systems such as the type IV and tight adherence pilus systems.
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Affiliation(s)
- Souvik Naskar
- Department of Infectious Disease, Imperial College, London, UK
| | - Michael Hohl
- Department of Infectious Disease, Imperial College, London, UK
| | | | - Harry H Low
- Department of Infectious Disease, Imperial College, London, UK
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Yu C, Nguyen DP, Ren Z, Liu J, Yang F, Tian F, Fan S, Chen H. The RpoN2-PilRX regulatory system governs type IV pilus gene transcription and is required for bacterial motility and virulence in Xanthomonas oryzae pv. oryzae. MOLECULAR PLANT PATHOLOGY 2020; 21:652-666. [PMID: 32112711 PMCID: PMC7170775 DOI: 10.1111/mpp.12920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 01/22/2020] [Accepted: 01/24/2020] [Indexed: 06/10/2023]
Abstract
The type IV pilus (T4P), a special class of bacterial surface filament, plays crucial roles in surface adhesion, motility, biofilm formation, and virulence in pathogenic bacteria. However, the regulatory mechanism of T4P and its relationship to bacterial virulence are still little understood in Xanthomonas oryzae pv. oryzae (Xoo), the causal pathogen of bacterial blight of rice. Our previous studies showed that the σ54 factor RpoN2 regulated bacterial virulence on rice in a flagellum-independent manner in Xoo. In this study, both yeast two-hybrid and pull-down assays revealed that RpoN2 directly and specifically interacted with PilRX, a homolog of the response regulator PilR of the two-component system PilS-PilR in the pilus gene cluster. Genomic sequence and reverse transcription PCR (RT-PCR) analysis showed 13 regulons containing 25 genes encoding T4P structural components and putative regulators. A consensus RpoN2-binding sequence GGN10 GC was identified in the promoter sequences of most T4P gene transcriptional units. Electrophoretic mobility shift assays confirmed the direct binding of RpoN2 to the promoter of the major pilin gene pilAX, the inner membrane platform protein gene pilCX, and pilRX. Promoter activity and quantitative RT-PCR assays demonstrated direct and indirect transcriptional regulation by RpoN2 of the T4P genes. In addition, individual deletions of pilAX, pilCX, and pilRX resulted in significantly reduced twitching and swimming motility, biofilm formation, and virulence in rice. Taken together, the findings from the current study suggest that the RpoN2-PilRX regulatory system controls bacterial motility and virulence by regulating T4P gene transcription in Xoo.
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Affiliation(s)
- Chao Yu
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Doan-Phuong Nguyen
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Zhaoyu Ren
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Jianan Liu
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Fenghuan Yang
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Fang Tian
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
| | - Susu Fan
- Shandong Provincial Key Laboratory of Applied MicrobiologyEcology InstituteQilu University of Technology (Shandong Academy of Sciences)Ji’nanChina
| | - Huamin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant ProtectionChinese Academy of Agricultural SciencesBeijingChina
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Qi YH, Huang L, Liu GF, Leng M, Lu GT. PilG and PilH antagonistically control flagellum-dependent and pili-dependent motility in the phytopathogen Xanthomonas campestris pv. campestris. BMC Microbiol 2020; 20:37. [PMID: 32070276 PMCID: PMC7029496 DOI: 10.1186/s12866-020-1712-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 01/27/2020] [Indexed: 12/27/2022] Open
Abstract
Background The virulence of the plant pathogen Xanthomonas campestris pv. campestris (Xcc) involves the coordinate expression of many virulence factors, including surface appendages flagellum and type IV pili, which are required for pathogenesis and the colonization of host tissues. Despite many insights gained on the structure and functions played by flagellum and pili in motility, biofilm formation, surface attachment and interactions with bacteriophages, we know little about how these appendages are regulated in Xcc. Results Here we present evidence demonstrating the role of two single domain response regulators PilG and PilH in the antagonistic control of flagellum-dependent (swimming) and pili-dependent (swarming) motility. Using informative mutagenesis, we reveal PilG positively regulates swimming motility while and negatively regulating swarming motility. Conversely, PilH negatively regulates swimming behaviour while and positively regulating swarming motility. By transcriptome analyses (RNA-seq and RT-PCR) we confirm these observations as PilG is shown to upregulate many genes involved chemotaxis and flagellar biosynthesis but these similar genes were downregulated by PilH. Co-immunoprecipitation, bacterial two-hybrid and pull-down analyses showed that PilH and PilG were able to interact with district subsets of proteins that potentially account for their regulatory impact. Additionally, we present evidence, using mutagenesis that PilG and PilH are involved in other cellular processes, including chemotaxis and virulence. Conclusions Taken together, we demonstrate that for the conditions tested PilG and PilH have inverse regulatory effects on flagellum-dependent and pili-dependent motility in Xcc and that this regulatory impact depends on these proteins influences on genes/proteins involved in flagellar biosynthesis and pilus assembly.
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Affiliation(s)
- Yan-Hua Qi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Li Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Guo-Fang Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Ming Leng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Guang-Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China.
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Structure and Properties of a Natural Competence-Associated Pilin Suggest a Unique Pilus Tip-Associated DNA Receptor. mBio 2019; 10:mBio.00614-19. [PMID: 31186316 PMCID: PMC6561018 DOI: 10.1128/mbio.00614-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Natural competence is the term used to describe the uptake of "naked" extracellular DNA by bacteria; it plays a significant role in horizontal genetic exchange. It is associated with type IV pili, and specialized competence pili mediate DNA uptake. Here, we show that the crystal structure of a competence-associated protein from Thermus thermophilus, ComZ, consists of a type II secretion pseudopilin-like domain, with a large β-solenoid domain inserted into the β-sheet of the pilin-like fold. ComZ binds with high affinity to another competence-associated pilin, PilA2, which lies adjacent to the comZ gene in the genome. The crystal structure of PilA2 revealed a similar type II secretion pseudopilin-like fold, with a small subdomain; docking simulations predicted that PilA2 binds between the pseudopilin-like and β-solenoid domains of ComZ. Electrophoretic shift analysis and DNase protection studies were used to show that ComZ alone and the ComZ/PilA2 complex are able to bind DNA. Protection against reductive dimethylation was used in combination with mass spectrometry and site-directed mutagenesis to identify two lysine residues in ComZ which are involved in DNA binding. They are located between the two domains in ComZ, on the opposite side from the predicted PilA2 binding site. These results suggest a model in which PilA2 assists ComZ in forming the competence pilus tip and DNA binds to the side of the fiber. The results demonstrate how a type IV pilin can be adapted to a specific function by domain insertion and provide the first structural insights into a tip-located competence pilin.IMPORTANCE Thermus thermophilus is a thermophilic bacterium which is capable of natural transformation, the uptake of external DNA with high efficiency. DNA uptake is thought to be mediated by a competence-associated pilus, which binds the DNA substrate and mediates its transfer across the outer membrane and periplasm. Here, we describe the structural and functional analysis of two pilins which are known to be essential for DNA uptake, ComZ and PilA2. ComZ adopts an unusual structure, incorporating a large β-solenoid domain into the pilin structural framework. We argue on structural grounds that this structure cannot readily be accommodated into the competence pilus fiber unless it is at the tip. We also show that ComZ binds DNA and identify two lysine residues which appear to be important for DNA binding. These results suggest a model in which ComZ and PilA2 form a tip-associated DNA receptor which mediates DNA uptake.
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Abstract
Type IV pilus (T4P)-like systems have been identified in almost every major phylum of prokaryotic life. They include the type IVa pilus (T4aP), type II secretion system (T2SS), type IVb pilus (T4bP), Tad/Flp pilus, Com pilus, and archaeal flagellum (archaellum). These systems are used for adhesion, natural competence, phage adsorption, folded-protein secretion, surface sensing, swimming motility, and twitching motility. The T4aP allows for all of these functions except swimming and is therefore a good model system for understanding T4P-like systems. Recent structural analyses have revolutionized our understanding of how the T4aP machinery assembles and functions. Here we review the structure and function of the T4aP.
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11
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Chang YW, Rettberg LA, Treuner-Lange A, Iwasa J, Søgaard-Andersen L, Jensen GJ. Architecture of the type IVa pilus machine. Science 2016; 351:aad2001. [PMID: 26965631 DOI: 10.1126/science.aad2001] [Citation(s) in RCA: 259] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 01/13/2016] [Indexed: 12/28/2022]
Abstract
Type IVa pili are filamentous cell surface structures observed in many bacteria. They pull cells forward by extending, adhering to surfaces, and then retracting. We used cryo-electron tomography of intact Myxococcus xanthus cells to visualize type IVa pili and the protein machine that assembles and retracts them (the type IVa pilus machine, or T4PM) in situ, in both the piliated and nonpiliated states, at a resolution of 3 to 4 nanometers. We found that T4PM comprises an outer membrane pore, four interconnected ring structures in the periplasm and cytoplasm, a cytoplasmic disc and dome, and a periplasmic stem. By systematically imaging mutants lacking defined T4PM proteins or with individual proteins fused to tags, we mapped the locations of all 10 T4PM core components and the minor pilins, thereby providing insights into pilus assembly, structure, and function.
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Affiliation(s)
- Yi-Wei Chang
- California Institute of Technology, Pasadena, CA 91125, USA. Howard Hughes Medical Institute, Pasadena, CA 91125, USA
| | - Lee A Rettberg
- Howard Hughes Medical Institute, Pasadena, CA 91125, USA
| | - Anke Treuner-Lange
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Janet Iwasa
- University of Utah, Salt Lake City, UT 84112, USA
| | | | - Grant J Jensen
- California Institute of Technology, Pasadena, CA 91125, USA. Howard Hughes Medical Institute, Pasadena, CA 91125, USA.
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12
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Bischof LF, Friedrich C, Harms A, Søgaard-Andersen L, van der Does C. The Type IV Pilus Assembly ATPase PilB of Myxococcus xanthus Interacts with the Inner Membrane Platform Protein PilC and the Nucleotide-binding Protein PilM. J Biol Chem 2016; 291:6946-57. [PMID: 26851283 DOI: 10.1074/jbc.m115.701284] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Indexed: 01/01/2023] Open
Abstract
Type IV pili (T4P) are ubiquitous bacterial cell surface structures, involved in processes such as twitching motility, biofilm formation, bacteriophage infection, surface attachment, virulence, and natural transformation. T4P are assembled by machinery that can be divided into the outer membrane pore complex, the alignment complex that connects components in the inner and outer membrane, and the motor complex in the inner membrane and cytoplasm. Here, we characterize the inner membrane platform protein PilC, the cytosolic assembly ATPase PilB of the motor complex, and the cytosolic nucleotide-binding protein PilM of the alignment complex of the T4P machinery ofMyxococcus xanthus PilC was purified as a dimer and reconstituted into liposomes. PilB was isolated as a monomer and bound ATP in a non-cooperative manner, but PilB fused to Hcp1 ofPseudomonas aeruginosaformed a hexamer and bound ATP in a cooperative manner. Hexameric but not monomeric PilB bound to PilC reconstituted in liposomes, and this binding stimulated PilB ATPase activity. PilM could only be purified when it was stabilized by a fusion with a peptide corresponding to the first 16 amino acids of PilN, supporting an interaction between PilM and PilN(1-16). PilM-N(1-16) was isolated as a monomer that bound but did not hydrolyze ATP. PilM interacted directly with PilB, but only with PilC in the presence of PilB, suggesting an indirect interaction. We propose that PilB interacts with PilC and with PilM, thus establishing the connection between the alignment and the motor complex.
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Affiliation(s)
- Lisa Franziska Bischof
- From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and the Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, D-79104 Freiburg, Germany
| | - Carmen Friedrich
- From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and
| | - Andrea Harms
- From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and
| | - Lotte Søgaard-Andersen
- From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and
| | - Chris van der Does
- From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and the Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, D-79104 Freiburg, Germany
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13
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Zhou X, Qian G, Chen Y, Du L, Liu F, Yuen GY. PilG is Involved in the Regulation of Twitching Motility and Antifungal Antibiotic Biosynthesis in the Biological Control Agent Lysobacter enzymogenes. PHYTOPATHOLOGY 2015; 105:1318-1324. [PMID: 26360465 DOI: 10.1094/phyto-12-14-0361-r] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Lysobacter enzymogenes strain C3 is a gliding bacterium which produces the antifungal secondary metabolite heat-stable antifungal factor (HSAF) and type IV pilus (T4P) as important mechanisms in biological control activity against fungal pathogens. To date, the regulators that control HSAF biosynthesis and T4P-dependent twitching motility in L. enzymogenes are poorly explored. In the present study, we addressed the role of pilG in the regulation of these two traits in L. enzymogenes. PilG of L. enzymogenes was found to be a response regulator, commonly known as a component of a two-component transduction system. Mutation of pilG in strain C3 abolished its ability to display spreading colony phenotype and cell movement at the colony margin, which is indicative of twitching motility; hence, PilG positively regulates twitching motility in L. enzymogenes. Mutation of pilG also enhanced HSAF production and the transcription of its key biosynthetic gene hsaf pks/nrps, suggesting that PilG plays a negative regulatory role in HSAF biosynthesis. This finding represents the first demonstration of the regulator PilG having a role in secondary metabolite biosynthesis in bacteria. Collectively, our results suggest that key ecological functions (HSAF production and twitching motility) in L. enzymogenes strain C3 are regulated in opposite directions by the same regulatory protein, PilG.
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Affiliation(s)
- Xue Zhou
- First, second, third, and fifth authors: College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education; fourth author: Department of Chemistry, University of Nebraska-Lincoln, 68588; fifth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, P.R. China; and sixth author: Department of Plant Pathology, University of Nebraska-Lincoln
| | - Guoliang Qian
- First, second, third, and fifth authors: College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education; fourth author: Department of Chemistry, University of Nebraska-Lincoln, 68588; fifth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, P.R. China; and sixth author: Department of Plant Pathology, University of Nebraska-Lincoln
| | - Yuan Chen
- First, second, third, and fifth authors: College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education; fourth author: Department of Chemistry, University of Nebraska-Lincoln, 68588; fifth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, P.R. China; and sixth author: Department of Plant Pathology, University of Nebraska-Lincoln
| | - Liangcheng Du
- First, second, third, and fifth authors: College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education; fourth author: Department of Chemistry, University of Nebraska-Lincoln, 68588; fifth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, P.R. China; and sixth author: Department of Plant Pathology, University of Nebraska-Lincoln
| | - Fengquan Liu
- First, second, third, and fifth authors: College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education; fourth author: Department of Chemistry, University of Nebraska-Lincoln, 68588; fifth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, P.R. China; and sixth author: Department of Plant Pathology, University of Nebraska-Lincoln
| | - Gary Y Yuen
- First, second, third, and fifth authors: College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education; fourth author: Department of Chemistry, University of Nebraska-Lincoln, 68588; fifth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, P.R. China; and sixth author: Department of Plant Pathology, University of Nebraska-Lincoln
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14
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Frye SA, Lång E, Beyene GT, Balasingham SV, Homberset H, Rowe AD, Ambur OH, Tønjum T. The Inner Membrane Protein PilG Interacts with DNA and the Secretin PilQ in Transformation. PLoS One 2015; 10:e0134954. [PMID: 26248334 PMCID: PMC4527729 DOI: 10.1371/journal.pone.0134954] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 07/15/2015] [Indexed: 11/19/2022] Open
Abstract
Expression of type IV pili (Tfp), filamentous appendages emanating from the bacterial surface, is indispensable for efficient neisserial transformation. Tfp pass through the secretin pore consisting of the membrane protein PilQ. PilG is a polytopic membrane protein, conserved in Gram-positive and Gram-negative bacteria, that is required for the biogenesis of neisserial Tfp. PilG null mutants are devoid of pili and non-competent for transformation. Here, recombinant full-length, truncated and mutated variants of meningococcal PilG were overexpressed, purified and characterized. We report that meningococcal PilG directly binds DNA in vitro, detected by both an electromobility shift analysis and a solid phase overlay assay. PilG DNA binding activity was independent of the presence of the consensus DNA uptake sequence. PilG-mediated DNA binding affinity was mapped to the N-terminus and was inactivated by mutation of residues 43 to 45. Notably, reduced meningococcal transformation of DNA in vivo was observed when PilG residues 43 to 45 were substituted by alanine in situ, defining a biologically significant DNA binding domain. N-terminal PilG also interacted with the N-terminal region of PilQ, which previously was shown to bind DNA. Collectively, these data suggest that PilG and PilQ in concert bind DNA during Tfp-mediated transformation.
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Affiliation(s)
- Stephan A. Frye
- Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | - Emma Lång
- Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | | | | | | | | | - Ole Herman Ambur
- Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | - Tone Tønjum
- Department of Microbiology, Oslo University Hospital, Oslo, Norway
- Department of Microbiology, University of Oslo, Oslo, Norway
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15
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Leighton TL, Buensuceso RNC, Howell PL, Burrows LL. Biogenesis of Pseudomonas aeruginosa type IV pili and regulation of their function. Environ Microbiol 2015; 17:4148-63. [PMID: 25808785 DOI: 10.1111/1462-2920.12849] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 03/13/2015] [Accepted: 03/14/2015] [Indexed: 12/27/2022]
Abstract
Type IV pili (T4P) are bacterial virulence factors involved in a wide variety of functions including deoxyribonucleic acid uptake, surface attachment, biofilm formation and twitching motility. While T4P are common surface appendages, the systems that assemble them and the regulation of their function differ between species. Pseudomonas aeruginosa, Neisseria spp. and Myxococcus xanthus are common model systems used to study T4P biology. This review focuses on recent advances in P. aeruginosa T4P structural biology, and the regulatory pathways controlling T4P biogenesis and function.
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Affiliation(s)
- Tiffany L Leighton
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Ryan N C Buensuceso
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - P Lynne Howell
- Program in Molecular Structure & Function, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Lori L Burrows
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
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16
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Hung MC, Christodoulides M. The biology of Neisseria adhesins. BIOLOGY 2013; 2:1054-109. [PMID: 24833056 PMCID: PMC3960869 DOI: 10.3390/biology2031054] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/01/2013] [Accepted: 07/03/2013] [Indexed: 01/15/2023]
Abstract
Members of the genus Neisseria include pathogens causing important human diseases such as meningitis, septicaemia, gonorrhoea and pelvic inflammatory disease syndrome. Neisseriae are found on the exposed epithelia of the upper respiratory tract and the urogenital tract. Colonisation of these exposed epithelia is dependent on a repertoire of diverse bacterial molecules, extending not only from the surface of the bacteria but also found within the outer membrane. During invasive disease, pathogenic Neisseriae also interact with immune effector cells, vascular endothelia and the meninges. Neisseria adhesion involves the interplay of these multiple surface factors and in this review we discuss the structure and function of these important molecules and the nature of the host cell receptors and mechanisms involved in their recognition. We also describe the current status for recently identified Neisseria adhesins. Understanding the biology of Neisseria adhesins has an impact not only on the development of new vaccines but also in revealing fundamental knowledge about human biology.
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Affiliation(s)
- Miao-Chiu Hung
- Neisseria Research, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, SO16 6YD, UK.
| | - Myron Christodoulides
- Neisseria Research, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, SO16 6YD, UK.
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17
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The type II secretion system – a dynamic fiber assembly nanomachine. Res Microbiol 2013; 164:545-55. [DOI: 10.1016/j.resmic.2013.03.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 02/28/2013] [Indexed: 11/17/2022]
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18
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Kolappan S, Craig L. Structure of the cytoplasmic domain of TcpE, the inner membrane core protein required for assembly of the Vibrio cholerae toxin-coregulated pilus. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:513-9. [PMID: 23519659 DOI: 10.1107/s0907444912050330] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 12/10/2012] [Indexed: 11/10/2022]
Abstract
Type IV pili are long thin surface-displayed polymers of the pilin subunit that are present in a diverse group of bacteria. These multifunctional filaments are critical to virulence for pathogens such as Vibrio cholerae, which use them to form microcolonies and to secrete the colonization factor TcpF. The type IV pili are assembled from pilin subunits by a complex inner membrane machinery. The core component of the type IV pilus-assembly platform is an integral inner membrane protein belonging to the GspF superfamily of secretion proteins. These proteins somehow convert chemical energy from ATP hydrolysis by an assembly ATPase on the cytoplasmic side of the inner membrane to mechanical energy for extrusion of the growing pilus filament out of the inner membrane. Most GspF-family inner membrane core proteins are predicted to have N-terminal and central cytoplasmic domains, cyto1 and cyto2, and three transmembrane segments, TM1, TM2 and TM3. Cyto2 and TM3 represent an internal repeat of cyto1 and TM1. Here, the 1.88 Å resolution crystal structure of the cyto1 domain of V. cholerae TcpE, which is required for assembly of the toxin-coregulated pilus, is reported. This domain folds as a monomeric six-helix bundle with a positively charged membrane-interaction face at one end and a hydrophobic groove at the other end that may serve as a binding site for partner proteins in the pilus-assembly complex.
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19
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Takhar HK, Kemp K, Kim M, Howell PL, Burrows LL. The platform protein is essential for type IV pilus biogenesis. J Biol Chem 2013; 288:9721-9728. [PMID: 23413032 DOI: 10.1074/jbc.m113.453506] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A systematic genetic analysis was performed to identify the inner membrane proteins essential for type IV pilus (T4P) expression in Pseudomonas aeruginosa. By inactivating the retraction aspect of pilus function, genes essential for T4P assembly were discriminated. In contrast to previous studies in the T4P system of Neisseria spp., we found that components of the inner membrane subcomplex consisting of PilMNOP were not essential for surface pilus expression, whereas the highly conserved inner membrane protein PilC was essential. Here, we present data that PilC may coordinate the activity of cytoplasmic polymerization (PilB) and depolymerization (PilT) ATPases via their interactions with its two cytoplasmic domains. Using in vitro co-affinity purification, we show that PilB interacts with the N-terminal cytoplasmic domain of PilC. We hypothesized that PilT similarly interacts with the PilC C-terminal cytoplasmic domain. Overexpression of that domain in the wild-type protein reduced twitching motility by ∼50% compared with the vector control. Site-directed mutagenesis of conserved T4P-specific residues in the PilC C-terminal domain yielded mutant proteins that supported wild-type pilus assembly but had a reduced capacity to support twitching motility, suggesting impairment of putative PilC-PilT interactions. Taken together, our results show that PilC is an essential inner membrane component of the T4P system, controlling both pilus assembly and disassembly.
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Affiliation(s)
- Herlinder K Takhar
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4K1
| | - Kevin Kemp
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4K1
| | - Melissa Kim
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4K1
| | - P Lynne Howell
- Program in Molecular Structure & Function, The Hospital for Sick Children, and the Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1X8, Canada.
| | - Lori L Burrows
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4K1.
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20
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McLaughlin LS, Haft RJF, Forest KT. Structural insights into the Type II secretion nanomachine. Curr Opin Struct Biol 2012; 22:208-16. [PMID: 22425326 DOI: 10.1016/j.sbi.2012.02.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/16/2012] [Accepted: 02/23/2012] [Indexed: 01/31/2023]
Abstract
The Type II secretion nanomachine transports folded proteins across the outer membrane of Gram-negative bacteria. Recent X-ray crystallography, electron microscopy, and molecular modeling studies provide structural insights into three functionally and spatially connected units of this nanomachine: the cytoplasmic and inner membrane energy-harvesting complex, the periplasmic helical pseudopilus, and the outer membrane secretin. Key advances include cryo-EM reconstruction of the secretin and demonstration that it interacts with both secreted substrates and a crucial transmembrane clamp protein, plus a biochemical and structural explanation of the role of low-abundance pseudopilins in initiating pseudopilus growth. Combining structures and protein interactions, we synthesize a 3D view of the complete complex consistent with a stepwise pathway in which secretin oligomerization defines sites of nanomachine biogenesis.
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21
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Lin YH, Ryan CS, Davies JK. Neisserial Correia repeat-enclosed elements do not influence the transcription of pil genes in Neisseria gonorrhoeae and Neisseria meningitidis. J Bacteriol 2011; 193:5728-36. [PMID: 21856854 PMCID: PMC3187199 DOI: 10.1128/jb.05526-11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2011] [Accepted: 08/08/2011] [Indexed: 11/20/2022] Open
Abstract
Two human-specific neisserial pathogens, Neisseria gonorrhoeae and Neisseria meningitidis, require the expression of type IV pili (tfp) for initial attachment to the host during infection. However, the mechanisms controlling the assembly and functionality of tfp are poorly understood. It is known that the gonococcal pilE gene, encoding the major subunit, is positively regulated by IHF, a multifunctional DNA binding protein. A neisserial specific repetitive DNA sequence, termed the Correia repeat-enclosed element (CREE) is situated upstream of three pil loci: pilHIJKX (pilH-X), pilGD, and pilF. CREEs have been shown to contain strong promoters, and some CREE variants contain a functional IHF binding site. CREEs might therefore be involved in the regulation of tfp biogenesis in pathogenic Neisseria. Site-directed and deletion mutagenesis on promoter::cat reporter constructs demonstrated that transcription of pilH-X and pilGD is from a σ(70) promoter and is independent of the CREE. The insertion of a CREE in the pilF promoter region in N. meningitidis generated a functional σ(70) promoter. However, there is also a functional promoter at this position in N. gonorrhoeae, where there is no CREE. These results suggest CREE insertion in these three pil loci does not influence transcription and that IHF does not coordinately regulate tfp biogenesis.
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Affiliation(s)
- Ya-Hsun Lin
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia.
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22
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Lemkul JA, Bevan DR. Characterization of interactions between PilA from Pseudomonas aeruginosa strain K and a model membrane. J Phys Chem B 2011; 115:8004-8. [PMID: 21630674 DOI: 10.1021/jp202217f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Type IV pili are important adhesion and motility factors in both gram-negative and gram-positive bacterial species, making pilus assembly from pilin subunits an important biophysical mechanism to understand at an atomic level. Knowledge of the pilus assembly mechanism has applications in antibiotic development, microbial physiology, and systems biology. We applied molecular dynamics simulations to investigate the position and orientation of Pseudomonas aeruginosa strain K PilA in a model membrane as well as the interactions of PilA with the surrounding lipids, identifying several key residues that stabilize the position of PilA within the membrane. Furthermore, we performed umbrella sampling to determine the free energy of extracting this protein from the membrane. Our results provide insight into the molecular events and energetics associated with pilus assembly, thereby initiating a detailed examination of the dynamics of this process.
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Affiliation(s)
- Justin A Lemkul
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
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23
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Ayers M, Howell PL, Burrows LL. Architecture of the type II secretion and type IV pilus machineries. Future Microbiol 2010; 5:1203-18. [PMID: 20722599 DOI: 10.2217/fmb.10.76] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Motility and protein secretion are key processes contributing to bacterial virulence. A wealth of phylogenetic, biochemical and structural evidence support the hypothesis that the widely distributed type IV pilus (T4P) system, involved in twitching motility, and the type II secretion (T2S) system, involved in exoprotein release, are descended from a common progenitor. Both are composed of dedicated but dynamic assemblages, which have been proposed to function through alternate polymerization and depolymerization or degradation of pilin-like subunits. While ongoing studies aimed at understanding the details of assembly and function of these systems are leading to new insights, there are still large knowledge gaps with respect to several fundamental aspects of their biology, including the localization and stoichiometry of critical assembly components, and the nature of their interactions. This article highlights recent advances in understanding the architectures of the T4P and T2S systems, and the organization of their inner and outer membrane components. As structural data accumulates, it is becoming increasingly apparent that even components with little-to-no sequence similarity have similar folds, further supporting the idea that both systems function by a similar mechanism.
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Affiliation(s)
- Melissa Ayers
- Department of Biochemistry & Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, ON, Canada
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24
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Karuppiah V, Hassan D, Saleem M, Derrick JP. Structure and oligomerization of the PilC type IV pilus biogenesis protein from Thermus thermophilus. Proteins 2010; 78:2049-57. [DOI: 10.1002/prot.22720] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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25
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Adalbjörnsson BV, Toogood HS, Fryszkowska A, Pudney CR, Jowitt TA, Leys D, Scrutton NS. Biocatalysis with Thermostable Enzymes: Structure and Properties of a Thermophilic ‘ene’-Reductase related to Old Yellow Enzyme. Chembiochem 2009; 11:197-207. [DOI: 10.1002/cbic.200900570] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Carbonnelle E, Hill DJ, Morand P, Griffiths NJ, Bourdoulous S, Murillo I, Nassif X, Virji M. Meningococcal interactions with the host. Vaccine 2009; 27 Suppl 2:B78-89. [PMID: 19481311 DOI: 10.1016/j.vaccine.2009.04.069] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Neisseria meningitidis interacts with host tissues through hierarchical, concerted and co-ordinated actions of a number of adhesins; many of which undergo antigenic and phase variation, a strategy that helps immune evasion. Three major structures, pili, Opa and Opc predominantly influence bacterial adhesion to host cells. Pili and Opa proteins also determine host and tissue specificity while Opa and Opc facilitate efficient cellular invasion. Recent studies have also implied a role of certain adhesin-receptor pairs in determining increased host susceptibility to infection. This chapter examines our current knowledge of meningococcal adhesion and invasion mechanisms particularly related to human epithelial and endothelial cells which are of primary importance in the disease process.
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Affiliation(s)
- Etienne Carbonnelle
- INSERM, unité 570, Université Paris Descartes, 156 rue de Vaugirard, Paris 75015, France
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27
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Schwarzenlander C, Haase W, Averhoff B. The role of single subunits of the DNA transport machinery of Thermus thermophilus HB27 in DNA binding and transport. Environ Microbiol 2009; 11:801-8. [PMID: 19396940 DOI: 10.1111/j.1462-2920.2008.01801.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Thermus thermophilus HB27 is well known for its extraordinary trait of high frequencies of natural transformation, which is considered a major mechanism of horizontal gene transfer. We show that the DNA translocator of T. thermophilus binds and transports DNA from members of all three domains. These results, together with the data obtained from genome comparisons, suggest that the DNA translocator of T. thermophilus has a major impact in adaptation of Thermus to thermal stress conditions and interdomain DNA transfer in extreme hot environments. DNA transport in T. thermophilus is mediated by a macromolecular transport machinery that consists of at least 16 subunits and spans the cytoplasmic membrane and the entire cell periphery. Here, we have addressed the role of single subunits in DNA binding and transport. PilQ is involved in DNA binding, ComEA, PilF and PilA4 are involved in transport of DNA through the outer membrane and PilM, PilN, PilO, PilA1-3, PilC and ComEC are essential for the transport of DNA through the thick cell wall layers and/or through the inner membrane. These data are discussed in the light of the subcellular localization of the proteins. A topological model for DNA transport across the cell wall is presented.
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Affiliation(s)
- Cornelia Schwarzenlander
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt am Main, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
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28
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Averhoff B. Shuffling genes around in hot environments: the unique DNA transporter ofThermus thermophilus. FEMS Microbiol Rev 2009; 33:611-26. [DOI: 10.1111/j.1574-6976.2008.00160.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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29
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Abendroth J, Mitchell DD, Korotkov KV, Johnson TL, Kreger A, Sandkvist M, Hol WGJ. The three-dimensional structure of the cytoplasmic domains of EpsF from the type 2 secretion system of Vibrio cholerae. J Struct Biol 2009; 166:303-15. [PMID: 19324092 DOI: 10.1016/j.jsb.2009.03.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 03/04/2009] [Accepted: 03/18/2009] [Indexed: 12/30/2022]
Abstract
The type 2 secretion system (T2SS), a multi-protein machinery that spans both the inner and the outer membranes of Gram-negative bacteria, is used for the secretion of several critically important proteins across the outer membrane. Here we report the crystal structure of the N-terminal cytoplasmic domain of EpsF, an inner membrane spanning T2SS protein from Vibrio cholerae. This domain consists of a bundle of six anti-parallel helices and adopts a fold that has not been described before. The long C-terminal helix alpha6 protrudes from the body of the domain and most likely continues as the first transmembrane helix of EpsF. Two N-terminal EpsF domains form a tight dimer with a conserved interface, suggesting that the observed dimer occurs in the T2SS of many bacteria. Two calcium binding sites are present in the dimer interface with ligands provided for each site by both subunits. Based on this new structure, sequence comparisons of EpsF homologs and localization studies of GFP fused with EpsF, we propose that the second cytoplasmic domain of EpsF adopts a similar fold as the first cytoplasmic domain and that full-length EpsF, and its T2SS homologs, have a three-transmembrane helix topology.
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Affiliation(s)
- Jan Abendroth
- Department of Biochemistry, Biomolecular Structure Center, University of Washington, 1959 Pacific Ave. NE, Box 357742, Seattle, WA 98195, USA
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30
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Allemand JF, Maier B. Bacterial translocation motors investigated by single molecule techniques. FEMS Microbiol Rev 2009; 33:593-610. [PMID: 19243443 DOI: 10.1111/j.1574-6976.2009.00166.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Translocation of DNA and protein fibers through narrow constrictions is a ubiquitous and crucial activity of bacterial cells. Bacteria use specialized machines to support macromolecular movement. A very important step toward a mechanistic understanding of these translocation machines is the characterization of their physical properties at the single molecule level. Recently, four bacterial transport processes have been characterized by nanomanipulation at the single molecule level, DNA translocation by FtsK and SpoIIIE, DNA import during transformation, and the related process of a type IV pilus retraction. With all four processes, the translocation rates, processivity, and stalling forces were remarkably high as compared with single molecule experiments with other molecular motors. Although substrates of all four processes proceed along a preferential direction of translocation, directionality has been shown to be controlled by distinct mechanisms.
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31
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Craig L, Li J. Type IV pili: paradoxes in form and function. Curr Opin Struct Biol 2008; 18:267-77. [PMID: 18249533 DOI: 10.1016/j.sbi.2007.12.009] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 12/12/2007] [Accepted: 12/12/2007] [Indexed: 01/24/2023]
Abstract
Type IV pili are filaments on the surfaces of many Gram-negative bacteria that mediate an extraordinary array of functions, including adhesion, motility, microcolony formation and secretion of proteases and colonization factors. Their prominent display on the surfaces of many bacterial pathogens, their vital role in virulence, and their ability to elicit an immune response make Type IV pilus structures particularly relevant for study as targets for component vaccines and therapies. Structural studies of the pili and components of the pilus assembly apparatus have proven extremely challenging, but new approaches and methods have produced important breakthroughs that are advancing our understanding of pilus functions and their complex assembly mechanism. These structures provide insights into the biology of Type IV pili as well as that of the related bacterial secretion and archaeal flagellar systems. This review will summarize the most recent structural advances on Type IV pili and their assembly components and highlight their significance.
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Affiliation(s)
- Lisa Craig
- Molecular Biology and Biochemistry Department, Simon Fraser University, 8888 University Dr., Burnaby, BC, Canada V5A 1S6.
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