scholarly journals Type II Protein Secretion in Pseudomonas aeruginosa: the Pseudopilus Is a Multifibrillar and Adhesive Structure

2003 ◽  
Vol 185 (9) ◽  
pp. 2749-2758 ◽  
Author(s):  
Éric Durand ◽  
Alain Bernadac ◽  
Geneviève Ball ◽  
Andrée Lazdunski ◽  
James N. Sturgis ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Hydrolytic Enzymes ◽  
Macromolecular Complex ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Secretion Systems ◽  
Type Iv Pilus ◽  
Type Iv ◽  
Type Iv Pilin

ABSTRACT The type II secretion pathway of Pseudomonas aeruginosa is involved in the extracellular release of various toxins and hydrolytic enzymes such as exotoxin A and elastase. This pathway requires the function of a macromolecular complex called the Xcp secreton. The Xcp secreton shares many features with the machinery involved in type IV pilus assembly. More specifically, it involves the function of five pilin-like proteins, the XcpT-X pseudopilins. We show that, upon overexpression, the XcpT pseudopilin can be assembled in a pilus, which we call a type II pseudopilus. Image analysis and filtering of electron micrographs indicated that these appendages are composed of individual fibrils assembled together in a bundle structure. Our observations thus revealed that XcpT has properties similar to those of type IV pilin subunits. Interestingly, the assembly of the type II pseudopilus is not exclusively dependent on the Xcp machinery but can be supported by other similar machineries, such as the Pil (type IV pilus) and Hxc (type II secretion) systems of P. aeruginosa. In addition, heterologous pseudopilins can be assembled by P. aeruginosa into a type II pseudopilus. Finally, we showed that assembly of the type II pseudopilus confers increased bacterial adhesive capabilities. These observations confirmed the ability of pseudopilins to form a pilus structure and raise questions with respect to their function in terms of secretion and adhesion, two crucial biological processes in the course of bacterial infections.

scholarly journals Structure of an Essential Type IV Pilus Biogenesis Protein Provides Insights into Pilus and Type II Secretion Systems

2012 ◽  
Vol 419 (1-2) ◽  
pp. 110-124 ◽  
Author(s):  
Atsushi Yamagata ◽  
Ekaterina Milgotina ◽  
Karen Scanlon ◽  
Lisa Craig ◽  
John A. Tainer ◽  
...  
Keyword(s):  
Type Ii Secretion ◽  
Type Ii ◽  
Secretion Systems ◽  
Type Iv Pilus ◽  
Type Iv ◽  
Pilus Biogenesis

scholarly journals Purification and Three-Dimensional Electron Microscopy Structure of the Neisseria meningitidis Type IV Pilus Biogenesis Protein PilG

2007 ◽  
Vol 189 (17) ◽  
pp. 6389-6396 ◽  
Author(s):  
Richard F. Collins ◽  
Muhammad Saleem ◽  
Jeremy P. Derrick
Keyword(s):  
Electron Microscopy ◽  
Neisseria Meningitidis ◽  
Metal Ion ◽  
Polyacrylamide Gel Electrophoresis ◽  
Three Dimensional ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Type Iv Pilus ◽  
Type Iv ◽  
Pilus Biogenesis

ABSTRACT Type IV pili are surface-exposed retractable fibers which play a key role in the pathogenesis of Neisseria meningitidis and other gram-negative pathogens. PilG is an integral inner membrane protein and a component of the type IV pilus biogenesis system. It is related by sequence to the extensive GspF family of secretory proteins, which are involved in type II secretion processes. PilG was overexpressed and purified from Escherichia coli membranes by detergent extraction and metal ion affinity chromatography. Analysis of the purified protein by perfluoro-octanoic acid polyacrylamide gel electrophoresis showed that PilG formed dimers and tetramers. A three-dimensional (3-D) electron microscopy structure of the PilG multimer was determined using single-particle averaging applied to samples visualized by negative staining. Symmetry analysis of the unsymmetrized 3-D volume provided further evidence that the PilG multimer is a tetramer. The reconstruction also revealed an asymmetric bilobed structure approximately 125 Å in length and 80 Å in width. The larger lobe within the structure was identified as the N terminus by location of Ni-nitrilotriacetic acid nanogold particles to the N-terminal polyhistidine tag. We propose that the smaller lobe corresponds to the periplasmic domain of the protein, with the narrower “waist” region being the transmembrane section. This constitutes the first report of a 3-D structure of a member of the GspF family and suggests a physical basis for the role of the protein in linking cytoplasmic and periplasmic protein components of the type II secretion and type IV pilus biogenesis systems.

scholarly journals Role of fimV in type II secretion system-dependent protein secretion of Pseudomonas aeruginosa on solid medium

Microbiology ◽  
2011 ◽  
Vol 157 (7) ◽  
pp. 1945-1954 ◽  
Author(s):  
Gérard P. F. Michel ◽  
Anthony Aguzzi ◽  
Geneviève Ball ◽  
Chantal Soscia ◽  
Sophie Bleves ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Solid Medium ◽  
Early Stage ◽  
Growth Conditions ◽  
Classical Type ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Secretion Systems ◽  
Type Ii Secretion System ◽  
Dependent Protein

Although classical type II secretion systems (T2SSs) are widely present in Gram-negative bacteria, atypical T2SSs can be found in some species. In Pseudomonas aeruginosa, in addition to the classical T2SS Xcp, it was reported that two genes, xphA and xqhA, located outside the xcp locus were organized in an operon (PaQa) which encodes the orphan PaQa subunit. This subunit is able to associate with other components of the classical Xcp machinery to form a functional hybrid T2SS. In the present study, using a transcriptional lacZ fusion, we found that the PaQa operon was more efficiently expressed (i) on solid LB agar than in liquid LB medium, (ii) at 25 °C than at 37 °C and (iii) at an early stage of growth. These results suggested an adaptation of the hybrid system to particular environmental conditions. Transposon mutagenesis led to the finding that vfr and fimV genes are required for optimal expression of the orphan PaQa operon in the defined growth conditions used. Using an original culturing device designed to monitor secretion on solid medium, the ring-plate system, we found that T2SS-dependent secretion of exoproteins, namely the elastase LasB, was affected in a fimV deletion mutant. Our findings led to the discovery of an interplay between FimV and the global regulator Vfr triggering the modulation of the level of Vfr and consequently the modulation of T2SS-dependent secretion on solid medium.

scholarly journals Natural Transformation of Campylobacter jejuni Requires Components of a Type II Secretion System

2003 ◽  
Vol 185 (18) ◽  
pp. 5408-5418 ◽  
Author(s):  
Rebecca S. Wiesner ◽  
David R. Hendrixson ◽  
Victor J. DiRita
Keyword(s):  
Campylobacter Jejuni ◽  
Natural Transformation ◽  
Bacterial Species ◽  
Type Ii Secretion ◽  
Dna Uptake ◽  
Type Ii ◽  
Secretion Systems ◽  
Dna Transport ◽  
Type Iv ◽  
Type Ii Secretion System

ABSTRACT The human pathogen Campylobacter jejuni is one of more than 40 naturally competent bacterial species able to import macromolecular DNA from the environment and incorporate it into their genomes. However, in C. jejuni little is known about the genes involved in this process. We used random transposon mutagenesis to identify genes that are required for the transformation of this organism. We isolated mutants with insertions in 11 different genes; most of the mutants are affected in the DNA uptake stage of transformation, whereas two mutants are affected in steps subsequent to DNA uptake, such as recombination into the chromosome or in DNA transport across the inner membrane. Several of these genes encode proteins homologous to those involved in type II secretion systems, biogenesis of type IV pili, and competence for natural transformation in gram-positive and gram-negative species. Other genes identified in our screen encode proteins unique to C. jejuni or are homologous to proteins that have not been shown to play a role in the transformation in other bacteria.

scholarly journals Type IV-Like Pili Formed by the Type II Secreton: Specificity, Composition, Bundling, Polar Localization, and Surface Presentation of Peptides

2003 ◽  
Vol 185 (11) ◽  
pp. 3416-3428 ◽  
Author(s):  
Guillaume Vignon ◽  
Rolf Köhler ◽  
Eric Larquet ◽  
Stéphanie Giroux ◽  
Marie-Christine Prévost ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Type Ii Secretion ◽  
Type Ii ◽  
High Level Expression ◽  
Polar Localization ◽  
Type Iv ◽  
C Terminus ◽  
Type Iv Pilin ◽  
High Level ◽  
K 12

ABSTRACT The secreton or type II secretion machinery of gram-negative bacteria includes several type IV pilin-like proteins (the pseudopilins) that are absolutely required for secretion. We previously reported the presence of a bundled pilus composed of the pseudopilin PulG on the surface of agar-grown Escherichia coli K-12 cells expressing the Klebsiella oxytoca pullulanase (Pul) secreton genes at high levels (N. Sauvonnet, G. Vignon, A. P. Pugsley, and P. Gounon, EMBO J. 19:2221-2228, 2000). We show here that PulG is the only pseudopilin in purified pili and that the phenomenon is not restricted to the Pul secreton reconstituted in E. coli or to PulG. For example, high-level expression of the endogenous E. coli gsp secreton genes caused production of bundled pili composed of the pseudopilin GspG, and the Pul secreton was able to form pili composed of PulG-like proteins from secreton systems of other bacteria. PulG derivatives in which the C terminus was extended by the addition of eight different peptides were also assembled into pili and functioned in secretion. Three of the C-terminal peptides were shown to be exposed along the entire length of the assembled pili. Hence, the C terminus of PulG may represent a permissive site for the insertion of immunogenic epitopes or other peptide sequences. One of these PulG variants, with a six-histidine tag at its C terminus, formed nonpolar, nonbundled pili, suggesting that bundle formation and polar localization are not correlated with the ability of PulG to function in secretion. We propose that the PulG pilus is an artifactual manifestation of a periplasmic “pseudopilus” and that cycles of pseudopilus extension and retraction within the periplasm propel pullulanase through secretin channels in the outer membrane. Abnormally long pili that extend beyond the outer membrane are produced only when pilus length control and retraction are deregulated by overproduction of the major pseudopilus subunit (PulG).

Architecture of the type II secretion and type IV pilus machineries

2010 ◽  
Vol 5 (8) ◽  
pp. 1203-1218 ◽  
Author(s):  
Melissa Ayers ◽  
P Lynne Howell ◽  
Lori L Burrows
Keyword(s):  
Type Ii Secretion ◽  
Type Ii ◽  
Type Iv Pilus ◽  
Type Iv

scholarly journals Roles of Putative Type II Secretion and Type IV Pilus Systems in the Virulence of Uropathogenic Escherichia coli

PLoS ONE ◽  
2009 ◽  
Vol 4 (3) ◽  
pp. e4752 ◽  
Author(s):  
Ritwij Kulkarni ◽  
Bijaya K. Dhakal ◽  
E. Susan Slechta ◽  
Zachary Kurtz ◽  
Matthew A. Mulvey ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Uropathogenic Escherichia Coli ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Type Iv Pilus ◽  
Type Iv

scholarly journals Export of the Pseudopilin XcpT of the Pseudomonas aeruginosa Type II Secretion System via the Signal Recognition Particle-Sec Pathway

2006 ◽  
Vol 189 (5) ◽  
pp. 2069-2076 ◽  
Author(s):  
Jorik Arts ◽  
Ria van Boxtel ◽  
Alain Filloux ◽  
Jan Tommassen ◽  
Margot Koster
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Protein Complexes ◽  
Signal Recognition Particle ◽  
Leader Peptide ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Signal Recognition ◽  
Amino Acid Residues ◽  
Reporter Protein ◽  
Type Iv

ABSTRACT Type IV pilins and pseudopilins are found in various prokaryotic envelope protein complexes, including type IV pili and type II secretion machineries of gram-negative bacteria, competence systems of gram-positive bacteria, and flagella and sugar-binding structures in members of the archaeal kingdom. The precursors of these proteins have highly conserved N termini, consisting of a short, positively charged leader peptide, which is cleaved off by a dedicated peptidase during maturation, and a hydrophobic stretch of approximately 20 amino acid residues. Which pathway is involved in the inner membrane translocation of these proteins is unknown. We used XcpT, the major pseudopilin from the type II secretion machinery of Pseudomonas aeruginosa, as a model to study this process. Transport of an XcpT-PhoA hybrid was shown to occur in the absence of other Xcp components in P. aeruginosa and in Escherichia coli. Experiments with conditional sec mutants and reporter-protein fusions showed that this transport process involves the cotranslational signal recognition particle targeting route and is dependent on a functional Sec translocon.

scholarly journals Activities of Pseudomonas aeruginosa Effectors Secreted by the Type III Secretion System In Vitro and during Infection

2005 ◽  
Vol 73 (3) ◽  
pp. 1695-1705 ◽  
Author(s):  
Vincent T. Lee ◽  
Roger S. Smith ◽  
Burkhard Tümmler ◽  
Stephen Lory
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Tissue Culture ◽  
Type Iii Secretion ◽  
Constitutive Expression ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Secretion Systems ◽  
Type Iii

ABSTRACT Pseudomonas aeruginosa utilizes a number of distinct pathways to secrete proteins that play various roles during infection. These include the type II secretion system, which is responsible for the secretion of the majority of exoproducts into the surrounding environment, including toxins and degradative enzymes. In contrast, the type III secretion system mediates the delivery of protein effectors directly into the cytoplasm of the host cell. Using tissue culture assays and a mouse acute-pneumonia model, we have determined the contribution of each of the type III effectors during infection. In strain PAK, ExoS is the major cytotoxin required for colonization and dissemination during infection. ExoT confers protection of tissue culture cells from type III-dependent lysis, while ExoY seemed to have little effect on cytotoxicity. ExoU is over 100-fold more cytotoxic than ExoS. The cytotoxicity of type II secretion was determined following deletion of the genes for the more toxic type III secretion system. The participation of these secretion systems during lifelong colonization of cystic fibrosis (CF) patients is unclear. By comparing clonal strains from the same patient isolated at the initial onset of P. aeruginosa infection and more than a decade later, after chronic colonization has been established, we show that initial strains are more cytotoxic than chronic strains that have evolved to reduce type III secretion. Constitutive expression of genes for the type III secretion system restored ExoS secretion but did not always reestablish cytotoxicity, suggesting that CF strains accumulate a number of mutations to reduce bacterial toxicity to the host.

Sign in / Sign up

Export Citation Format

Share Document