scholarly journals Identification of Substrates and Chaperone from the Yersinia enterocolitica 1B Ysa Type III Secretion System

2003 ◽  
Vol 71 (1) ◽  
pp. 242-253 ◽  
Author(s):  
Boris Foultier ◽  
Paul Troisfontaines ◽  
Didier Vertommen ◽  
Marie-Noëlle Marenne ◽  
Mark Rider ◽  
...  
Keyword(s):  
Yersinia Enterocolitica ◽  
Type Iii Secretion ◽  
Shigella Flexneri ◽  
Secretion System ◽  
Open Reading Frames ◽  
Target Cells ◽  
Type Iii ◽  
Genes Encoding ◽  
Reading Frames

ABSTRACT All pathogenic Yersinia enterocolitica strains carry the pYV plasmid encoding the Ysc-Yop type III secretion (TTS) system, which operates at 37°C. In addition, biovar 1B Y. enterocolitica strains possess a second, chromosomally encoded, TTS system called Ysa, which operates, at least in vitro, under low-temperature and high-salt (LTHS) conditions. Six open reading frames, sycB, yspB, yspC, yspD, yspA, and acpY, neighbor the ysa genes encoding the Ysa TTS apparatus. Here we show that YspA, YspB, YspC, and YspD are secreted by the Ysa TTS system under LTHS conditions. SycB is a chaperone for YspB and YspC and stabilizes YspB. YspB, YspC, and SycB share some similarity with TTS substrates and the chaperone encoded by the Mxi-Spa locus of Shigella flexneri and SPI-1 of Salmonella enterica. In addition, Ysa also secretes the pYV-encoded YopE under LTHS conditions, indicating that YopE is a potential effector of both Y. enterocolitica TTS systems. YspC could also be secreted by S. flexneri, but no functional complementation of ipaC was observed, which indicates that despite their similarity the Ysa and the Mxi-Spa systems are not interchangeable. When expressed from the yopE promoter, YspB and YspC could also be secreted via the Ysc injectisome. However, they could not form detectable pores in eukaryotic target cells and could not substitute for YopB and YopD for translocation of Yop effectors.

scholarly journals Mutations in Salmonella Pathogenicity Island 2 (SPI2) Genes Affecting Transcription of SPI1 Genes and Resistance to Antimicrobial Agents

1998 ◽  
Vol 180 (18) ◽  
pp. 4775-4780 ◽  
Author(s):  
Jörg Deiwick ◽  
Thomas Nikolaus ◽  
Jaqueline E. Shea ◽  
Colin Gleeson ◽  
David W. Holden ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Antimicrobial Agents ◽  
Type Iii Secretion System ◽  
Polymyxin B ◽  
Secretion System ◽  
Effector Proteins ◽  
Secretion Systems ◽  
Type Iii ◽  
Genes Encoding

ABSTRACT The Salmonella typhimurium genome contains two pathogenicity islands (SPI) with genes encoding type III secretion systems for virulence proteins. SPI1 is required for the penetration of the epithelial layer of the intestine. SPI2 is important for the subsequent proliferation of bacteria in the spleens of infected hosts. Although most mutations in SPI2 lead to a strong reduction of virulence, they have different effects in vitro, with some mutants having significantly increased sensitivity to gentamicin and the antibacterial peptide polymyxin B. Previously we showed that certain mutations in SPI2 affect the ability of S. typhimurium to secrete SPI1 effector proteins and to invade cultured eukaryotic cells. In this study, we show that these SPI2 mutations affect the expression of the SPI1 invasion genes. Analysis of reporter fusions to various SPI1 genes reveals highly reduced expression of sipC,prgK, and hilA, the transcriptional activator of SPI1 genes. These observations indicate that the expression of one type III secretion system can be influenced dramatically by mutations in genes encoding a second type III secretion system in the same cell.

scholarly journals The Shiga Toxin 1-Converting Bacteriophage BP-4795 Encodes an NleA-Like Type III Effector Protein

2005 ◽  
Vol 187 (24) ◽  
pp. 8494-8498 ◽  
Author(s):  
Kristina Creuzburg ◽  
Jürgen Recktenwald ◽  
Volker Kuhle ◽  
Sylvia Herold ◽  
Michael Hensel ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
Type Iii Secretion ◽  
Regulatory Region ◽  
Secretion System ◽  
Open Reading Frames ◽  
Effector Protein ◽  
Type Iii Effector ◽  
Type Iii ◽  
Enterocyte Effacement ◽  
Reading Frames

ABSTRACT In this study, the complete DNA sequence of Shiga toxin 1-converting bacteriophage BP-4795 was determined. The genome of BP-4795 consists of 85 open reading frames, including two complete IS629 elements and three morons at the end of its late regulatory region. One of these morons encodes a type III effector that is translocated by the locus of enterocyte effacement-encoded type III secretion system into HeLa cells, where it localizes with the Golgi apparatus.

scholarly journals Regulation of the Ysa Type III Secretion System of Yersinia enterocolitica by YsaE/SycB and YsrS/YsrR

2004 ◽  
Vol 186 (13) ◽  
pp. 4056-4066 ◽  
Author(s):  
Kimberly A. Walker ◽  
Virginia L. Miller
Keyword(s):  
Yersinia Enterocolitica ◽  
Type Iii Secretion ◽  
Shigella Flexneri ◽  
Wild Type ◽  
Secretion Systems ◽  
Type Iii ◽  
Regulatory Cascade ◽  
Two Component

ABSTRACT Yersinia enterocolitica biovar 1B contains two type III secretion systems (TTSSs), the plasmid-encoded Ysc-Yop system and the chromosomally encoded Ysa-Ysp system. Proteins secreted from the Ysa TTSS (Ysps) have only been detected in vitro when cells are cultured at 26°C in a high-NaCl medium. However, the exact role of the Ysa TTSS is unclear. Thus, investigations into the regulation of this system may help elucidate the role of the Ysps during the life cycle of Y. enterocolitica. Here we present evidence that the AraC-like regulator YsaE acts together with the chaperone SycB to regulate transcription of the sycByspBCDA operon, a phenomenon similar to that seen in the closely related Salmonella SPI-1 and Shigella flexneri Mxi-Spa-Ipa TTSSs. Deletion of either sycB or ysaE results in a twofold reduction in the activity of a sycB-lacZ fusion compared to the wild type. In a reconstituted Escherichia coli system, transcription of sycB was activated sixfold only when both YsaE and SycB were present, demonstrating that they are necessary for activation. ysrR and ysrS are located near the ysa genes and encode a putative two-component regulatory system. Mutations in either gene indicated that both YsrR and YsrS were required for secretion of Ysps. In addition, transcription from sycB-lacZ and ysaE-lacZ fusions was decreased 6.5- and 25-fold, respectively, in the ysrS mutant compared to the wild type. Furthermore, in the absence of NaCl, the activity of ysaE-lacZ was reduced 25-fold in the wild-type and ΔysrS strains, indicating that YsrS is probably required for the salt-dependent expression of the ysa locus. These results suggest that the putative two-component system YsrRS may be a key element in the regulatory cascade for the Ysa TTSS.

scholarly journals The ADP-Ribosylating Toxin, AexT, from Aeromonas salmonicida subsp. salmonicida Is Translocated via a Type III Secretion Pathway

2003 ◽  
Vol 185 (22) ◽  
pp. 6583-6591 ◽  
Author(s):  
Sarah E. Burr ◽  
Katja Stuber ◽  
Joachim Frey
Keyword(s):  
Type Iii Secretion ◽  
Aeromonas Salmonicida ◽  
Open Reading Frames ◽  
Type Iii ◽  
Secretion Pathway ◽  
Cultured Fish ◽  
Genes Encoding ◽  
Fish Cells ◽  
Adp Ribosyltransferase ◽  
Reading Frames

ABSTRACT AexT is an extracellular ADP ribosyltransferase produced by the fish pathogen Aeromonas salmonicida subsp. salmonicida. The protein is secreted by the bacterium via a recently identified type III secretion system. In this study, we have identified a further 12 open reading frames that possess high homology to genes encoding both structural and regulatory components of the Yersinia type III secretion apparatus. Using marker replacement mutagenesis of aopB, the A. salmonicida subsp. salmonicida homologue of yopB in Yersinia, we demonstrate that the bacterium translocates the AexT toxin directly into the cytosol of cultured fish cells via this type III secretion pathway. An acrV mutant of A. salmonicida subsp. salmonicida displays a calcium-blind phenotype, expressing and secreting significant amounts of AexT even in the presence of CaCl2 concentrations as high as 10 mM. This acrV mutant is also unable to translocate AexT into the cytosol of fish cells, indicating AcrV is involved in the translocation process. Inactivation of either the aopB or acrV gene in A. salmonicida subsp. salmonicida (resulting in an inability to translocate AexT) is accompanied by a loss of cytotoxicity that can be restored by trans complementation. Finally, we present data indicating that preincubation of the wild-type bacteria with antibodies directed against recombinant AcrV-His protein provides fish cells protection against the toxic effects of the bacterium.

scholarly journals CesD2 of Enteropathogenic Escherichia coli Is a Second Chaperone for the Type III Secretion Translocator Protein EspD

2003 ◽  
Vol 71 (4) ◽  
pp. 2130-2141 ◽  
Author(s):  
Bianca C. Neves ◽  
Rosanna Mundy ◽  
Liljana Petrovska ◽  
Gordon Dougan ◽  
Stuart Knutton ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Effector Proteins ◽  
Translocator Protein ◽  
Type Iii ◽  
Genes Encoding

ABSTRACT Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli are extracellular pathogens that employ a type III secretion system to export translocator and effector proteins, proteins which facilitates colonization of the mucosal surface of the intestine via formation of attaching and effacing (A/E) lesions. The genes encoding the proteins for A/E lesion formation are located on a pathogenicity island, termed the locus of enterocyte effacement (LEE), which contains eae encoding intimin as well as the type III secretion system and effector genes. Many type III secreted proteins are stabilized and maintained in a secretion-competent conformation in the bacterial cytosol by specific chaperone proteins. Three type III chaperones have been described thus far within the EPEC LEE region: CesD, for the translocator proteins EspB and EspD; CesT, for the effector proteins Tir and Map; and CesF, for EspF. In this study we report the characterization of CesD2 (previously Orf27), a second LEE-encoded chaperone for EspD. We show specific CesD2-EspD protein interaction which appears to be necessary for proper EspD secretion in vitro and pathogenesis in vivo as demonstrated in the A/E-lesion-forming mouse pathogen Citrobacter rodentium.

scholarly journals The Vibrio cholerae trh Gene Is Coordinately RegulatedIn Vitrowith Type III Secretion System Genes by VttRA/VttRBbut Does Not Contribute to Caco2-BBE Cell Cytotoxicity

2012 ◽  
Vol 80 (12) ◽  
pp. 4444-4455 ◽  
Author(s):  
Kelly A. Miller ◽  
Elaine Hamilton ◽  
Michelle Dziejman
Keyword(s):  
Vibrio Cholerae ◽  
Type Iii Secretion ◽  
Genomic Island ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Dependent Manner ◽  
Content Type ◽  
Type Iii ◽  
Genes Encoding

ABSTRACTNumerous virulence factors have been associated with pathogenic non-O1/non-O139 serogroup strains ofVibrio cholerae. Among them are thethermostabledirecthemolysin (TDH) and theTDH-relatedhemolysin (TRH), which share amino acid similarities to the TDH and TRH proteins ofVibrio parahaemolyticus, where they have been shown to contribute to pathogenesis. Although TDH and TRH homologs can be encoded on extrachromosomal elements inV. cholerae, type III secretion system (T3SS)-positive strains, such as AM-19226, carry a copy oftrhwithin the T3SS genomic island. Transcriptional fusion analysis showed that in strain AM-19226,trhexpression is regulated in a bile-dependent manner by a family of transmembrane transcriptional regulators that includes VttRA, VttRB, and ToxR. Genes encoding T3SS structural components are expressed under similar conditions, suggesting that within the T3SS genomic island, genes encoding proteins unrelated to the T3SS and loci involved in T3SS synthesis are coregulated. Despite similarin vitroexpression patterns, however, TRH is not required for AM-19226 to colonize the infant mouse intestine, nor does it contribute to bile-mediated cytotoxicity when strain AM-19226 is cocultured with the mammalian cell line Caco2-BBE. Instead, we found that a functional T3SS is essential for AM-19226 to induce bile-mediated cytotoxicityin vitro. Collectively, the results are consistent with a more minor role for theV. choleraeTRH in T3SS-positive strains compared to the functions attributed to theV. parahaemolyticusTDH and TRH proteins.

scholarly journals Transcriptional Slippage in mxiE Controls Transcription and Translation of the Downstream mxiD Gene, Which Encodes a Component of the Shigella flexneri Type III Secretion Apparatus

2006 ◽  
Vol 188 (3) ◽  
pp. 1196-1198 ◽  
Author(s):  
Christophe Penno ◽  
Claude Parsot
Keyword(s):  
Type Iii Secretion ◽  
Shigella Flexneri ◽  
Open Reading Frames ◽  
Transcription Activator ◽  
Gene Encoding ◽  
Essential Component ◽  
Type Iii ◽  
Overlapping Open Reading Frames ◽  
Transcriptional Slippage ◽  
Reading Frames

ABSTRACT The Shigella flexneri transcription activator MxiE is produced by transcriptional slippage from two overlapping open reading frames. By using plasmids encoding a mxiD-lacZ translational fusion, we showed that transcriptional slippage in mxiE influences both transcription and translation of the downstream mxiD gene encoding an essential component of the type III secretion apparatus.

scholarly journals Dynamic relocalization of cytosolic type III secretion system components prevents premature protein secretion at low external pH

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Stephan Wimmi ◽  
Alexander Balinovic ◽  
Hannah Jeckel ◽  
Lisa Selinger ◽  
Dimitrios Lampaki ◽  
...  
Keyword(s):  
Yersinia Enterocolitica ◽  
Protein Secretion ◽  
Type Iii Secretion ◽  
Shigella Flexneri ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Host Cells ◽  
Type Iii ◽  
Partial Dissociation ◽  
External Ph

AbstractMany bacterial pathogens use a type III secretion system (T3SS) to manipulate host cells. Protein secretion by the T3SS injectisome is activated upon contact to any host cell, and it has been unclear how premature secretion is prevented during infection. Here we report that in the gastrointestinal pathogens Yersinia enterocolitica and Shigella flexneri, cytosolic injectisome components are temporarily released from the proximal interface of the injectisome at low external pH, preventing protein secretion in acidic environments, such as the stomach. We show that in Yersinia enterocolitica, low external pH is detected in the periplasm and leads to a partial dissociation of the inner membrane injectisome component SctD, which in turn causes the dissociation of the cytosolic T3SS components. This effect is reversed upon restoration of neutral pH, allowing a fast activation of the T3SS at the native target regions within the host. These findings indicate that the cytosolic components form an adaptive regulatory interface, which regulates T3SS activity in response to environmental conditions.

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