scholarly journals Heterologous assembly of type IV pili by a type II secretion system reveals the role of minor pilins in assembly initiation

2012 ◽  
Vol 86 (4) ◽  
pp. 805-818 ◽  
Author(s):  
David A. Cisneros ◽  
Gerard Pehau-Arnaudet ◽  
Olivera Francetic
Keyword(s):  
Secretion System ◽  
Type Iv Pili ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Type Iv ◽  
Type Ii Secretion System

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 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 The role of intrinsic disorder and dynamics in the assembly and function of the type II secretion system

2017 ◽  
Vol 1865 (10) ◽  
pp. 1255-1266 ◽  
Author(s):  
Shuang Gu ◽  
Vladimir E. Shevchik ◽  
Rosie Shaw ◽  
Richard W. Pickersgill ◽  
James A. Garnett
Keyword(s):  
Intrinsic Disorder ◽  
Secretion System ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Type Ii Secretion System ◽  
And Function

scholarly journals Type IV pili and type II secretion play a limited role in Legionella pneumophila biofilm colonization and retention

Microbiology ◽  
2006 ◽  
Vol 152 (12) ◽  
pp. 3569-3573 ◽  
Author(s):  
Claressa E. Lucas ◽  
Ellen Brown ◽  
Barry S. Fields
Keyword(s):  
Legionella Pneumophila ◽  
Wild Type Strain ◽  
Water Systems ◽  
Type Iv Pili ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Wild Type ◽  
Intracellular Replication ◽  
Type Iv

Legionellae colonize biofilms in building water systems, yet little is known about their interaction with the organisms in these microbial communities. The role of Legionella pneumophila type IV pili and the type II secretion pre-pilin peptidase was evaluated in a model biofilm system. L. pneumophila strains 130b (wild-type), BS100 (a type IV pili mutant) and NU243 (a pre-pilin peptidase mutant) were assessed for attachment and retention in an established biofilm. Strains 130b and NU243 colonized the biofilm at a similar level while BS100 attached at a tenfold lower level. Over time, NU243 dropped below the level of detection while BS100 remained in the biofilm throughout the course of the experiment. The wild-type strain decreased but remained at a considerably higher level than either of the mutants. Inclusion of amoebae with BS100 allowed for attachment and retention at a level similar to 130b. NU243, which displays reduced intracellular replication, was able to establish itself and persist in the presence of amoebae. Thus, type IV pili and the pre-pilin peptidase facilitate L. pneumophila colonization of biofilms but are not required in the presence of a host for intracellular replication.

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 Photobacterium damselae subsp. damselae Major Virulence Factors Dly, Plasmid-Encoded HlyA, and Chromosome-Encoded HlyA Are Secreted via the Type II Secretion System

2015 ◽  
Vol 83 (4) ◽  
pp. 1246-1256 ◽  
Author(s):  
Amable J. Rivas ◽  
Ana Vences ◽  
Matthias Husmann ◽  
Manuel L. Lemos ◽  
Carlos R. Osorio
Keyword(s):  
Secretion System ◽  
Transcriptional Level ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Marine Animals ◽  
Content Type ◽  
Type Ii Secretion System ◽  
Photobacterium Damselae ◽  
Prepilin Peptidase

Photobacterium damselaesubsp.damselaeis a marine bacterium that causes septicemia in marine animals and in humans. Previously, we had determined a major role of pPHDD1 plasmid-encoded Dly (damselysin) and HlyA (HlyApl) and the chromosome-encoded HlyA (HlyAch) hemolysins in virulence. However, the mechanisms by which these toxins are secreted remain unknown. In this study, we found that a mini-Tn10transposon mutant in a plasmidless strain showing an impaired hemolytic phenotype contained an insertion inepsL, a component of a type II secretion system (T2SS). Reconstruction of the mutant by allelic exchange confirmed the specific involvement ofepsLin HlyAchsecretion. In addition, mutation ofepsLin a pPHDD1-harboring strain caused an almost complete abolition of hemolytic activity against sheep erythrocytes, indicating thatepsLplays a major role in secretion of the plasmid-encoded HlyApland Dly. This was further demonstrated by analysis of different combinations of hemolysin gene mutants and by strain-strain complementation assays. We also found that mutation of the putative prepilin peptidase genepilDseverely affected hemolysis, which dropped at levels inferior to those ofepsLmutants. Promoter expression analyses suggested that impairment of hemolysin secretion inepsLandpilDmutants might constitute a signal that affects hemolysin and T2SS gene expression at the transcriptional level. In addition, singleepsLandpilDmutations caused a drastic decrease in virulence for mice, demonstrating a major role of T2SS andpilDinP. damselaesubsp.damselaevirulence.

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