The Type III Secretion Pathway: Dictating the Outcome of Bacterial-Host Interactions

2000 ◽  
pp. 203-224 ◽  
Keyword(s):  
Type Iii Secretion ◽  
Bacterial Host ◽  
Host Interactions ◽  
Type Iii ◽  
Secretion Pathway

scholarly journals Environmental Regulation and Virulence Attributes of the Ysa Type III Secretion System of Yersinia enterocolitica Biovar 1B

2005 ◽  
Vol 73 (9) ◽  
pp. 5961-5977 ◽  
Author(s):  
Krista Venecia ◽  
Glenn M. Young
Keyword(s):  
Yersinia Enterocolitica ◽  
Type Iii Secretion ◽  
Chromosomal Locus ◽  
Host Interactions ◽  
Type Iii ◽  
Genes Encoding ◽  
Transposon Mutants ◽  
Phase Temperature ◽  
Mouse Model Of Infection ◽  
Definitive Role

ABSTRACT Pathogenic biovars of Yersinia enterocolitica maintain the well-studied plasmid-encoded Ysc type III secretion (TTS) system, which has a definitive role in virulence. Y. enterocolitica biovar 1B additionally has a distinct chromosomal locus, the Yersinia secretion apparatus pathogenicity island (YSA PI) that encodes the Ysa TTS system. The signals to which the Ysa TTS system responds and its role in virulence remain obscure. This exploratory study was conducted to define environmental cues that promote the expression of Ysa TTS genes and to define how the Ysa TTS system influences bacterium-host interactions. Using a genetic approach, a collection of Y. enterocolitica Ysa TTS mutants was generated by mutagenesis with a transposon carrying promoterless lacZYA. This approach identified genes both within and outside of the YSA PI that contribute to Ysa TTS. Expression of these genes was regulated in response to growth phase, temperature, NaCl, and pH. Additional genetic analysis demonstrated that two regulatory genes encoding components of the YsrR-YsrS (ysrS) and RcsC-YojN-RcsB (rcsB) phosphorelay systems affect the expression of YSA PI genes and each other. The collection of Ysa TTS-defective transposon mutants, along with other strains carrying defined mutations that block Ysa and Ysc TTS, was examined for changes in virulence properties by using the BALB/c mouse model of infection. This analysis revealed that the Ysa TTS system impacts the ability of Y. enterocolitica to colonize gastrointestinal tissues. These results reveal facets of how Y. enterocolitica controls the function of the Ysa TTS system and uncovers a role for the Ysa TTS during the gastrointestinal phase of infection.

scholarly journals Interactions of the Type III Secretion Pathway Proteins LcrV and LcrG fromYersinia pestisAre Mediated by Coiled-Coil Domains

2002 ◽  
Vol 277 (41) ◽  
pp. 38714-38722 ◽  
Author(s):  
Daniel G. Lawton ◽  
Colin Longstaff ◽  
B. A. Wallace ◽  
Jim Hill ◽  
Sophie E. C. Leary ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Coiled Coil ◽  
Type Iii ◽  
Secretion Pathway

scholarly journals Pseudolipasin A Is a Specific Inhibitor for Phospholipase A2 Activity of Pseudomonas aeruginosa Cytotoxin ExoU

2006 ◽  
Vol 75 (3) ◽  
pp. 1089-1098 ◽  
Author(s):  
Vincent T. Lee ◽  
Stefan Pukatzki ◽  
Hiromi Sato ◽  
Eriya Kikawada ◽  
Anastasia A. Kazimirova ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Iii Secretion ◽  
Specific Inhibitor ◽  
Effector Proteins ◽  
Host Cells ◽  
Cytotoxic Effects ◽  
Type Iii ◽  
Secretion Pathway ◽  
Phospholipase A2 Activity

ABSTRACT A number of bacterial pathogens utilize the type III secretion pathway to deliver effector proteins directly into the host cell cytoplasm. Certain strains of Pseudomonas aeruginosa associated with acute infections express a potent cytotoxin, exoenzyme U (ExoU), that is delivered via the type III secretion pathway directly into contacting host cells. Once inside the mammalian cell, ExoU rapidly lyses the intoxicated cells via its phospholipase A2 (PLA2) activity. A high-throughput cell-based assay was developed to screen libraries of compounds for those capable of protecting cells against the cytotoxic effects of ExoU. A number of compounds were identified in this screen, including one group that blocks the intracellular activity of ExoU. In addition, these compounds specifically inhibited the PLA2 activity of ExoU in vitro, whereas eukaryotic secreted PLA2 and cytosolic PLA2 were not inhibited. This novel inhibitor of ExoU-specific PLA2 activity, named pseudolipasin A, may provide a new lead for virulence factor-based therapeutic design.

scholarly journals Impassable YscP Substrates and Their Impact on the Yersinia enterocolitica Type III Secretion Pathway

2008 ◽  
Vol 190 (18) ◽  
pp. 6204-6216 ◽  
Author(s):  
Kelly E. Riordan ◽  
Joseph A. Sorg ◽  
Bryan J. Berube ◽  
Olaf Schneewind
Keyword(s):  
Type Iii Secretion ◽  
Host Cells ◽  
Block Type ◽  
Reporter Protein ◽  
Secrete Protein ◽  
Protein Substrates ◽  
Type Iii ◽  
Secretion Signal ◽  
Secretion Pathway ◽  
Partial Blockade

ABSTRACT Yersinia type III machines secrete protein substrates across the bacterial envelope and, following assembly of their secretion needles, transport effector Yops into host cells. According to their destination during type III secretion, early, middle, and late secretion substrates can be distinguished; however, the signals and mechanisms whereby these proteins are recognized and transported by the secretion machine are not understood. Here, we examine several hybrids between secretion substrates and the impassable reporter protein glutathione S-transferase (GST). YscP-GST and YopR-GST blocked type III secretion; however, YscF-, YopD-, YopN-, and LcrV-GST did not. Unlike YopR-GST, which can block type III machines only during their assembly, expression of YscP-GST led to an immediate and complete block of all secretion. The secretion signal of YscP was mapped to its first 10 codons or amino acids; however, YscPΔ2-15-GST, lacking this secretion signal, imposed a partial blockade. YscP-GST copurified with the type III ATPase complex (YscN, YscL, and YscQ) and with YscO, suggesting that the association of specific machine components with the impassable substrate may cause the block in type III secretion.

scholarly journals Spa15 of Shigella flexneri, a third type of chaperone in the type III secretion pathway

2002 ◽  
Vol 43 (6) ◽  
pp. 1533-1542 ◽  
Author(s):  
Anne-Laure Page ◽  
Philippe Sansonetti ◽  
Claude Parsot
Keyword(s):  
Type Iii Secretion ◽  
Shigella Flexneri ◽  
Type Iii ◽  
Secretion Pathway

scholarly journals The Secretion Signal of YopN, a Regulatory Protein of the Yersinia enterocolitica Type III Secretion Pathway

2004 ◽  
Vol 186 (18) ◽  
pp. 6320-6324 ◽  
Author(s):  
John W. Goss ◽  
Joseph A. Sorg ◽  
Kumaran S. Ramamurthi ◽  
Hung Ton-That ◽  
Olaf Schneewind
Keyword(s):  
Yersinia Enterocolitica ◽  
Type Iii Secretion ◽  
Regulatory Protein ◽  
Signal Function ◽  
Type Iii ◽  
Synonymous Mutations ◽  
Secretion Signal ◽  
Secretion Pathway ◽  
Hybrid Proteins ◽  
Fusion Approach

ABSTRACT The type III secretion signal of Yersinia enterocolitica YopN was mapped using a gene fusion approach. yopN codons 1 to 12 were identified as critical for signal function. Several synonymous mutations that abolish secretion of hybrid proteins without altering the codon specificity of yopN mRNA were identified.

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 Erwinia amylovora Secretes DspE, a Pathogenicity Factor and Functional AvrE Homolog, through the Hrp (Type III Secretion) Pathway

1998 ◽  
Vol 180 (8) ◽  
pp. 2244-2247 ◽  
Author(s):  
Adam J. Bogdanove ◽  
David W. Bauer ◽  
Steven V. Beer
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Minimal Medium ◽  
Erwinia Amylovora ◽  
Specific Antiserum ◽  
Type Iii ◽  
Secretion Pathway ◽  
Pathogenicity Factor ◽  
Functional Homolog

ABSTRACT Erwinia amylovora was shown to secrete DspE, a pathogenicity factor of 198 kDa and a functional homolog of AvrE ofPseudomonas syringae pv. tomato. DspE was identified among the supernatant proteins isolated from cultures grown in anhrp gene-inducing minimal medium by immunodetection with a DspE-specific antiserum. Secretion required an intact Hrp pathway.

scholarly journals Impact of Inactivated Extracellular Proteases on the Modified Flagellin Type III Secretion Pathway of Bacillus halodurans

2008 ◽  
Vol 75 (1) ◽  
pp. 271-274 ◽  
Author(s):  
Eldie Berger ◽  
Erika du Plessis ◽  
Isak Gerber ◽  
Michael Crampton ◽  
Nolwandle Nxumalo ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Gene Fusion ◽  
Bacillus Halodurans ◽  
Extracellular Proteases ◽  
Flagellin Gene ◽  
Type Iii ◽  
Secretion Pathway ◽  
The Stability ◽  
Targeted Inactivation

ABSTRACT The flagellin type III secretion pathway of Bacillus halodurans BhFC01 (Δhag) was modified by the inactivation of fliD. An in-frame flagellin gene fusion polypeptide construct was expressed, and the heterologous peptides were secreted as flagellin fusion monomers. The stability of the secreted monomers was significantly enhanced through gene-targeted inactivation of extracellular proteases.

Sign in / Sign up

Export Citation Format

Share Document