Secretion of type III effectors into host cells in real time

2005 ◽  
Vol 2 (12) ◽  
pp. 959-965 ◽  
Author(s):  
Jost Enninga ◽  
Joëlle Mounier ◽  
Philippe Sansonetti ◽  
Guy Tran Van Nhieu
Keyword(s):  
Real Time ◽  
Host Cells ◽  
Type Iii Effectors ◽  
Type Iii

Real-time monitoring of translocation of selected type-III effectors from Xanthomonas oryzae pv. oryzae into rice cells

2019 ◽  
Vol 44 (4) ◽  
Author(s):  
Huijie Bian ◽  
Liyuan Zhang ◽  
Lei Chen ◽  
Wenzhan Wang ◽  
Hongtao Ji ◽  
...  
Keyword(s):  
Real Time ◽  
Xanthomonas Oryzae ◽  
Real Time Monitoring ◽  
Type Iii Effectors ◽  
Type Iii

scholarly journals Characterization of the hrpF Pathogenicity Peninsula of Xanthomonas oryzae pv. oryzae

2005 ◽  
Vol 18 (6) ◽  
pp. 546-554 ◽  
Author(s):  
Akiko Sugio ◽  
Bing Yang ◽  
Frank F. White
Keyword(s):  
Gene Clusters ◽  
Hypersensitive Reaction ◽  
Xanthomonas Oryzae ◽  
Host Cells ◽  
Host Specialization ◽  
Rice Cultivars ◽  
Type Iii Effectors ◽  
Type Iii ◽  
The Right ◽  
And Function

The hrp gene cluster of Xanthomonas spp. contains genes for the assembly and function of a type III secretion system (TTSS). The hrpF genes reside in a region between hpaB and the right end of the hrp cluster. The region of the hrpF gene of Xanthomonas oryzae pv. oryzae is bounded by two IS elements and also contains a homolog of hpaF of X. campestris pv. vesicatoria and two newly identified genes, hpa3 and hpa4. A comparison of the hrp gene clusters of different species of Xanthomonas revealed that the hrpF region is a constant yet more variable peninsula of the hrp pathogenicity island. Mutations in hpaF, hpa3, and hpa4 had no effect on virulence, whereas hrpF mutants were severely reduced in virulence on susceptible rice cultivars. The hrpF genes from X. campestris pv. vesicatoria, X. campestris pv. campestris, and X. axonopodis pv. citri each were capable of restoring virulence to the hrpF mutant of X. oryzae pv. oryzae. Correspondingly, none of the Xanthomonas pathovars with hrpF from X. oryzae pv. oryzae elicited a hypersensitive reaction in their respective hosts. Therefore, no evidence was found for hrpF as a host-specialization factor. In contrast to the loss of Bs3-dependent reactions by hrpF mutants of X. campestris pv. vesicatoria, hrpF mutants of X. oryzae pv. oryzae with either avrXa10 or avrXa7 elicited hypersensitive reactions in rice cultivars with the corresponding R genes. A double hrpFxoo-hpa1 mutant also elicited an Xa10-dependent resistance reaction. Thus, loss of hrpF, hpa1, or both may reduce delivery or effectiveness of type III effectors. However, the mutations did not completely prevent the delivery of effectors from X. oryzae pv. oryzae into the host cells.

scholarly journals Enteropathogenic Escherichia coli Type III Effectors EspG and EspG2 Alter Epithelial Paracellular Permeability

2005 ◽  
Vol 73 (10) ◽  
pp. 6283-6289 ◽  
Author(s):  
Takeshi Matsuzawa ◽  
Asaomi Kuwae ◽  
Akio Abe
Keyword(s):  
Escherichia Coli ◽  
Tight Junctions ◽  
Mdck Cells ◽  
Disease Process ◽  
Paracellular Permeability ◽  
Host Cells ◽  
Knockout Mutant ◽  
Double Knockout ◽  
Type Iii Effectors ◽  
Type Iii

ABSTRACT Enteropathogenic Escherichia coli (EPEC) delivers a subset of effectors into host cells via a type III secretion system. Here we show that the type III effector EspG and its homologue EspG2 alter epithelial paracellular permeability. When MDCK cells were infected with wild-type (WT) EPEC, RhoA was activated, and this event was dependent on the delivery of either EspG or EspG2 into host cells. In contrast, a loss of transepithelial electrical resistance and ZO-1 disruption were induced by infection with an espG/espG2 double-knockout mutant, as was the case with the WT EPEC, indicating that EspG/EspG2 is not involved in the disruption of tight junctions during EPEC infection. Although EspG- and EspG2-expressing MDCK cells exhibited normal overall morphology and maintained fully assembled tight junctions, the paracellular permeability to 4-kDa dextran, but not the paracellular permeability to 500-kDa dextran, was greatly increased. This report reveals for the first time that a pathogen can regulate the size-selective paracellular permeability of epithelial cells in order to elicit a disease process.

scholarly journals Synthetic bottom-up approach reveals the complex interplay ofShigellaeffectors in regulation of epithelial cell death

2018 ◽  
Vol 115 (25) ◽  
pp. 6452-6457 ◽  
Author(s):  
Xiangyu Mou ◽  
Skye Souter ◽  
Juan Du ◽  
Analise Z. Reeves ◽  
Cammie F. Lesser
Keyword(s):  
Cell Death ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Host Cells ◽  
Bottom Up ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Bacterial Replication ◽  
Almost All ◽  
Epithelial Cell Death

Over the course of an infection, many Gram-negative bacterial pathogens use complex nanomachines to directly inject tens to hundreds of proteins (effectors) into the cytosol of infected host cells. These effectors rewire processes to promote bacterial replication and spread. The roles of effectors in pathogenesis have traditionally been investigated by screening for phenotypes associated with their absence, a top-down approach that can be limited, as effectors often act in a functionally redundant or additive manner. Here we describe a syntheticEscherichia coli-based bottom-up platform to conduct gain-of-function screens for roles of individualShigellaeffectors in pathogenesis. As proof of concept, we screened forShigellaeffectors that limit cell death induced on cytosolic entry of bacteria into epithelial cells. Using this platform, in addition to OspC3, an effector known to inhibit cell death via pyroptosis, we have identified OspD2 and IpaH1.4 as cell death inhibitors. In contrast to almost all type III effectors, OspD2 does not target a host cell process, but rather regulates the activity of theShigellatype III secretion apparatus limiting the cytosolic delivery (translocation) of effectors during an infection. Remarkably, by limiting the translocation of a single effector, VirA, OspD2 controls the timing of epithelial cell death via calpain-mediated necrosis. Together, these studies provide insight into the intricate manner by whichShigellaeffectors interact to establish a productive intracytoplasmic replication niche before the death of infected epithelial cells.

scholarly journals Pangenomic type III effector database of the plant pathogenic Ralstonia spp.

2019 ◽  
Author(s):  
Cyrus Raja Rubenstein Sabbagh ◽  
Sébastien Carrère ◽  
Fabien Lonjon ◽  
Fabienne Vailleau ◽  
Alberto P Macho ◽  
...  
Keyword(s):  
Species Complex ◽  
Plant Pathogens ◽  
Gene Annotation ◽  
Plant Immunity ◽  
Host Cells ◽  
Plant Host ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Bacterial Wilt Disease ◽  
Wide Range

Background. The bacterial plant pathogenic Ralstonia species belong to the beta-proteobacteria order and are soil-borne pathogens causing the vascular bacterial wilt disease, affecting a wide range of plant hosts. These bacteria form a heterogeneous group considered as a “species complex”,” gathering three newly defined species. Like many other Gram negative plant pathogens, Ralstonia pathogenicity relies on a type III secretion system, enabling bacteria to secrete/inject a large repertoire of type III effectors into their plant host cells. T3Es are thought to participate in generating a favorable environment for the pathogen (countering plant immunity and modifying the host metabolism and physiology). Methods. Expert genome annotation, followed by specific type III-dependent secretion, allowed us to improve our Hidden-Markov-Model and Blast profiles for the prediction of type III effectors. Results. We curated the T3E repertoires of 12 plant pathogenic Ralstoniastrains, representing a total of 12 strains spread over the different groups of the species complex. This generated a pangenome repertoire of 102 T3E genes and 16 hypothetical T3E genes. Using this database, we scanned for the presence of T3Es in the 155 available genomes representing 140 distinct plant pathogenic Ralstonia strains isolated from different host plants in different areas of the globe. All this information is presented in a searchable database. A presence/absence analysis, modulated by a strain sequence/gene annotation quality score, enabled us to redefine core and accessory T3E repertoires.

scholarly journals The HopX (AvrPphE) Family of Pseudomonas syringae Type III Effectors Require a Catalytic Triad and a Novel N-Terminal Domain for Function

2007 ◽  
Vol 20 (4) ◽  
pp. 346-357 ◽  
Author(s):  
Zachary L. Nimchuk ◽  
Emily J. Fisher ◽  
Darrell Desveaux ◽  
Jeffery H. Chang ◽  
Jeffery L. Dangl
Keyword(s):  
Pseudomonas Syringae ◽  
Legionella Pneumophila ◽  
Specific Interaction ◽  
Catalytic Triad ◽  
Host Cells ◽  
Secretion Systems ◽  
Interaction Domain ◽  
Biochemical Basis ◽  
Type Iii Effectors ◽  
Type Iii

Many gram-negative plant pathogenic bacteria employ type III secretion systems to deliver effector proteins directly into the host cell during infection. On susceptible hosts, type III effectors aid pathogen growth by manipulating host defense pathways. On resistant hosts, some effectors can activate specific host disease resistance (R) genes, leading to generation of rapid and effective immune responses. The biochemical basis of these processes is poorly understood. The HopX (AvrPphE) family is a widespread type III effector among phytopathogenic bacteria. We determined that HopX family members are modular proteins composed of a conserved putative cysteine-based catalytic triad and a conserved potential target/cofactor interaction domain. HopX is soluble in host cells. Putative catalytic triad residues are required for avirulence activity on resistant bean hosts and for the generation of a cell-death response in specific Arabidopsis genotypes. The putative target/cofactor interaction domain is also required for these activities. Our data suggest that specific interaction with and modification of a cytosolic host target drives HopX recognition in resistant hosts and may contribute to virulence in susceptible hosts. Surprisingly, the Legionella pneumophila genome was found to contain a protein with similarity to HopX in sequence and domain arrangement, suggesting that these proteins might also contribute to animal pathogenesis and could be delivered to plant and animal hosts by diverse secretion systems.

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