scholarly journals Type IV Fimbrial Biogenesis Is Required for Protease Secretion and Natural Transformation in Dichelobacter nodosus

2007 ◽  
Vol 189 (14) ◽  
pp. 5022-5033 ◽  
Author(s):  
Xiaoyan Han ◽  
Ruth M. Kennan ◽  
Dane Parker ◽  
John K. Davies ◽  
Julian I. Rood
Keyword(s):  
Natural Transformation ◽  
Secretion System ◽  
Extracellular Protease ◽  
Classical Type ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Dichelobacter Nodosus ◽  
Type Iv ◽  
Type Ii Secretion System ◽  
Protease Secretion

ABSTRACT The objective of this study was to develop an understanding of the molecular mechanisms by which type IV fimbrial biogenesis, natural transformation, and protease secretion are linked in the ovine foot rot pathogen, Dichelobacter nodosus. We have shown that like the D. nodosus fimbrial subunit FimA, the pilin-like protein PilE and the FimN, FimO, and FimP proteins, which are homologs of PilB, PilC, and PilD from Pseudomonas aeruginosa, are essential for fimbrial biogenesis and natural transformation, indicating that transformation requires an intact type IV fimbrial apparatus. The results also showed that extracellular protease secretion in the fimN, fimO, fimP, and pilE mutants was significantly reduced, which represents the first time that PilB, PilC, and PilE homologs have been shown to be required for the secretion of unrelated extracellular proteins in a type IV fimbriate bacterium. Quantitative real-time PCR analysis of the three extracellular protease genes aprV2, aprV5, and bprV showed that the effects on protease secretion were not mediated at the transcriptional level. Bioinformatic analysis did not identify a classical type II secretion system, and the putative fimbrial biogenesis gene pilQ was the only outer membrane secretin gene identified. Based on these results, it is postulated that in D. nodosus, protease secretion occurs by a type II secretion-related process that directly involves components of the type IV fimbrial biogenesis machinery, which represents the only type II secretion system encoded by the small genome of this highly evolved pathogen.

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 In vivo structure of the Legionella type II secretion system by electron cryotomography

2019 ◽  
Author(s):  
Debnath Ghosal ◽  
Ki Woo Kim ◽  
Huaixin Zheng ◽  
Mohammed Kaplan ◽  
Joseph P. Vogel ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Cell Envelope ◽  
Secretion System ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Type Iv ◽  
Type Ii Secretion System ◽  
Wide Range ◽  
Electron Cryotomography

AbstractThe type II secretion system (T2SS) is a multi-protein envelope-spanning assembly that translocates a wide range of virulence factors, enzymes and effectors through the outer membrane (OM) of many Gram-negative bacteria. Here, using electron cryotomography and subtomogram averaging methods, we present the first in situ structure of an intact T2SS, imaged within the human pathogen Legionella pneumophila. Although the T2SS has only limited sequence and component homology with the evolutionarily-related Type IV pilus (T4P) system, we show that their overall architectures are remarkably similar. Despite similarities, there are also differences, including for instance that the T2SS-ATPase complex is usually present but disengaged from the inner membrane, the T2SS has a much longer periplasmic vestibule, and it has a short-lived flexible pseudopilus. Placing atomic models of the components into our ECT map produced a complete architectural model of the intact T2SS that provides new insights into the structure and function of its components, its position within the cell envelope, and the interactions between its different subcomplexes. Overall, these structural results strongly support the piston model for substrate extrusion.

scholarly journals Multidisciplinary Interrogation of a Crucial Protein Interface in the Type II Secretion System

2020 ◽  
Author(s):  
Cristian A Escobar ◽  
Badreddine Douzi ◽  
Geneviève Ball ◽  
Brice Barbat ◽  
Sebastien Alphonse ◽  
...  
Keyword(s):  
Structural Model ◽  
Secretion System ◽  
Type Iv Pili ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Type Iv ◽  
Type Ii Secretion System ◽  
Biophysical Techniques ◽  
Membrane Spanning

The type IV filament superfamily comprises widespread membrane-associated polymers in prokaryotes. The Type II secretion system (T2SS), a significant virulence pathway in many pathogens, belongs to this superfamily. A knowledge gap in understanding of the T2SS is the molecular role of a small 'pseudopilin' protein. Using multiple biophysical techniques, we have deciphered how this missing component of the Xcp T2SS architecture is structurally integrated, and thereby also unlocked its function. We demonstrate that the low abundance XcpH is the adapter that bridges a trimeric initiating tip complex XcpIJK with a periplasmic filament of XcpG subunits. Our model reveals that each pseudopilin protein caps an XcpG protofilament in an overall pseudopilus compatible with dimensions of the periplasm and the outer membrane-spanning secretin through which substrates of the T2SS pass. Unexpectedly, to fulfill its adapter function, the XcpH N-terminal helix must be unwound, a property shared with XcpG subunits. We provide the first complete structural model of a type IV filament, a result immediately transferable to understanding of other T2SS and the type IV pili.

scholarly journals Solution Structure of Homology Region (HR) Domain of Type II Secretion System

2012 ◽  
Vol 287 (12) ◽  
pp. 9072-9080 ◽  
Author(s):  
Shuang Gu ◽  
Geoff Kelly ◽  
Xiaohui Wang ◽  
Tom Frenkiel ◽  
Vladimir E. Shevchik ◽  
...  
Keyword(s):  
Solution Structure ◽  
Secretion System ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Homology Region ◽  
Type Ii Secretion System
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