scholarly journals A volume rendered visualization of a Yersinia enterocolitica bacterium containing clusters of type III secretion systems (injectisomes) as imaged by cryo-electron tomography (injectisomes in red, cell envelope in blue). Clustering of type III secretion sy

2015 ◽  
Vol 95 (5) ◽  
pp. i-i
Keyword(s):  
Yersinia Enterocolitica ◽  
Type Iii Secretion ◽  
Electron Tomography ◽  
Cell Envelope ◽  
Red Cell ◽  
Secretion Systems ◽  
Type Iii ◽  
Type Iii Secretion Systems ◽  
Cryo Electron Tomography

scholarly journals An Amino-Terminal Secretion Signal Is Required for YplA Export by the Ysa, Ysc, and Flagellar Type III Secretion Systems of Yersinia enterocolitica Biovar 1B

2005 ◽  
Vol 187 (17) ◽  
pp. 6075-6083 ◽  
Author(s):  
Sasha M. Warren ◽  
Glenn M. Young
Keyword(s):  
Yersinia Enterocolitica ◽  
Type Iii Secretion ◽  
Distinct Type ◽  
Host Cells ◽  
Amino Acid Residues ◽  
Secretion Systems ◽  
Type Iii ◽  
Secretion Signal ◽  
Amino Terminal ◽  
Type Iii Secretion Systems

ABSTRACT Yersinia enterocolitica biovar 1B maintains three distinct type III secretion (TTS) systems, which independently operate to target proteins to extracellular sites. The Ysa and Ysc systems are prototypical contact-dependent TTS systems that translocate toxic effectors to the cytosols of targeted eukaryotic host cells during infection. The flagellar TTS system is utilized during the assembly of the flagellum and is required for secretion of the virulence-associated phospholipase YplA to the bacterial milieu. When ectopically produced, YplA is also a secretion substrate for the Ysa and Ysc TTS systems. In this study, we define elements that allow YplA recognition and export by the Ysa, Ysc, and flagellar TTS systems. Fusion of various amino-terminal regions of YplA to Escherichia coli alkaline phosphatase (PhoA) lacking its native secretion signal demonstrated that the first 20 amino acids or corresponding mRNA codons of YplA were sufficient for export of YplA-PhoA chimeras by each TTS system. Export of native YplA by each of the three TTS systems was also found to depend on the integrity of its amino terminus. Introduction of a frameshift mutation or deletion of yplA sequences encoding the amino-terminal 20 residues negatively impacted YplA secretion. Deletion of other yplA regions was tolerated, including that resulting in the removal of amino acid residues 30 through 40 of the polypeptide and removal of the 5′ untranslated region of the mRNA. This work supports a model in which independent and distantly related TTS systems of Y. enterocolitica recognize protein substrates by a similar mechanism.

scholarly journals Evidence for Targeting of Yop Effectors by the Chromosomally Encoded Ysa Type III Secretion System of Yersinia enterocolitica

2002 ◽  
Vol 184 (20) ◽  
pp. 5563-5571 ◽  
Author(s):  
Briana M. Young ◽  
Glenn M. Young
Keyword(s):  
Yersinia Enterocolitica ◽  
Type Iii Secretion ◽  
Immunoblot Analysis ◽  
Effector Proteins ◽  
Secretion Systems ◽  
Necrosis Factor Alpha ◽  
Type Iii ◽  
Type Iii Secretion Systems ◽  
Molecular Masses ◽  
Factor Alpha

ABSTRACT Yersinia enterocolitica O:8 has two contact-dependent type III secretion systems (TTSSs). The Ysa TTSS is encoded by a set of genes located on the chromosome and exports Ysp proteins. The Ysc TTSS and the Yop effector proteins it exports are encoded by genes located on plasmid pYVe8081. In this study, secretion of YspG, YspH, and YspJ by the Ysa TTSS was shown to require pYVe8081. Furthermore, mutations that blocked the function of the Ysc TTSS did not affect YspG, YspH, and YspJ production. This indicated that YspG, YspH, and YspJ are encoded by genes located on pYVe8081 and that they may correspond to Yops. A comparison of Ysps with Yop effectors secreted by Y. enterocolitica indicated that YspG, YspH, and YspJ have apparent molecular masses similar to those of YopN, YopP, and YopE, respectively. Immunoblot analysis demonstrated that antibodies directed against YopN, YopP, and YopE recognized YspG, YspH, and YspJ. Furthermore, mutations in yopN, yopP, and yopE specifically blocked YopN, YopP, and YopE secretion by the Ysc TTSS and YspG, YspH, and YspJ secretion by the Ysa TTSS. These results indicate YspG, YspH, and YspJ are actually YopN, YopP, and YopE. Additional analysis demonstrated that YopP and YspH secretion was restored to yopP mutants by complementation in trans with a wild-type copy of the yopP gene. Examination of Y. enterocolitica-infected J774A.1 macrophages revealed that both the Ysc and Ysa TTSSs contribute to YopP-dependent suppression of tumor necrosis factor alpha production. This indicates that both the Ysa and Ysc TTSSs are capable of targeting YopP and that they influence Y. enterocolitica interactions with macrophages. Taken together, these results suggest that the Ysa and Ysc TTSSs contribute to Y. enterocolitica virulence by exporting both unique and common subsets of effectors.

scholarly journals Identification of Potential Type III Secretion Proteins via Heterologous Expression of Vibrio parahaemolyticus DNA

2012 ◽  
Vol 78 (9) ◽  
pp. 3492-3494 ◽  
Author(s):  
Xiaohui Zhou ◽  
Seth D. Nydam ◽  
Jeffrey E. Christensen ◽  
Michael E. Konkel ◽  
Lisa Orfe ◽  
...  
Keyword(s):  
Heterologous Expression ◽  
Yersinia Enterocolitica ◽  
Type Iii Secretion ◽  
Vibrio Parahaemolyticus ◽  
Genomic Islands ◽  
Secretion Systems ◽  
Content Type ◽  
Type Iii ◽  
Type Iii Secretion Systems ◽  
Secretion Assay

ABSTRACTWe employed a heterologous secretion assay to identify proteins potentially secreted by type III secretion systems (T3SSs) inVibrio parahaemolyticus. N-terminal sequences from 32 proteins within T3SS genomic islands and seven proteins from elsewhere in the chromosome included proteins that were recognized for export by theYersinia enterocoliticaflagellar T3SS.

scholarly journals Synchronous Gene Expression of the Yersinia enterocolitica Ysa Type III Secretion System and Its Effectors

2009 ◽  
Vol 191 (6) ◽  
pp. 1816-1826 ◽  
Author(s):  
Kimberly A. Walker ◽  
Virginia L. Miller
Keyword(s):  
Yersinia Enterocolitica ◽  
Type Iii Secretion ◽  
Response Regulator ◽  
Solid Surfaces ◽  
Dual Function ◽  
Secretion Systems ◽  
Type Iii ◽  
Virulence Plasmids ◽  
Type Iii Secretion Systems ◽  
Genes Encoding

ABSTRACT Type III secretion systems (T3SSs) are complex units that consist of many proteins. Often the proteins are encoded as a cohesive unit on virulence plasmids, but several systems have their various components dispersed around the chromosome. The Yersinia enterocolitica Ysa T3SS is such a system, where the apparatus genes, some regulatory genes, and four genes encoding secreted proteins (ysp genes) are contained in a single locus. The remaining ysp genes and at least one additional regulator are found elsewhere on the chromosome. Expression of ysa genes requires conditions of high ionic strength, neutral/basic pH, and low temperatures (26°C) and is stimulated by exposure to solid surfaces. The AraC-like regulator YsaE and the dual-function chaperone/regulator SycB are required to stimulate the sycB promoter, which transcribes sycB and probably yspBCDA as well. The putative phosphorelay proteins YsrRS (located at the distal end of the ysa locus) and RcsB, the response regulator of the RcsBCD phosphorelay system, are required to initiate transcription at the ysaE promoter, which drives transcription of many apparatus genes. In this work, we sought to determine which ysp genes were coordinately regulated with the genes within the ysa locus. We found that six unlinked ysp genes responded to NaCl and required YsaE/SycB, YsrRS, and RcsB for expression. Three ysp genes had unique patterns, one of which was unaffected by all elements tested except NaCl. Thus, while the ysp genes were likely to have been acquired independently, most have acquired a synchronous regulatory pattern.

scholarly journals Visualization of the type III secretion mediated Salmonella -host cell interface using cryo-electron tomography

2018 ◽  
Author(s):  
Jun Liu ◽  
Donghyun Park ◽  
Maria Lara-Tejero ◽  
Jorge E Galan ◽  
Wenwei Li ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Host Cell ◽  
Type Iii Secretion ◽  
Electron Tomography ◽  
Host Cells ◽  
Target Cells ◽  
Secretion Systems ◽  
Type Iii ◽  
Cryo Electron Tomography ◽  
Cell Interface

Many important gram-negative bacterial pathogens use highly sophisticated type III secretion systems (T3SSs) to establish complex host-pathogen interactions. Bacterial-host cell contact triggers the activation of the T3SS and the subsequent insertion of a translocon pore into the target cell membrane, which serves as a conduit for the passage of effector proteins. Therefore the initial interaction between T3SS-bearing bacteria and host cells is the critical step in the deployment of the protein secretion machine, yet this process remains poorly understood. Here, we use high-throughput cryo-electron tomography (cryo-ET) to visualize the T3SS-mediated Salmonella -host cell interface. Our analysis reveals the intact translocon at an unprecedented level of resolution, its deployment in the host cell membrane, and the establishment of an intimate association between the bacteria and the target cells, which is essential for effector translocation. Our studies provide critical data supporting the long postulated direct injection model for effector translocation.

scholarly journals YplA Is Exported by the Ysc, Ysa, and Flagellar Type III Secretion Systems of Yersinia enterocolitica

2002 ◽  
Vol 184 (5) ◽  
pp. 1324-1334 ◽  
Author(s):  
Briana M. Young ◽  
Glenn M. Young
Keyword(s):  
Yersinia Enterocolitica ◽  
Protein Secretion ◽  
Type Iii Secretion ◽  
Pathogenic Bacteria ◽  
Chloride Concentration ◽  
Effector Proteins ◽  
Secretion Systems ◽  
Type Iii ◽  
Type Iii Secretion Systems ◽  
Type Iii Protein Secretion

ABSTRACT Yersinia enterocolitica maintains three different pathways for type III protein secretion. Each pathway requires the activity of a specific multicomponent apparatus or type III secretion system (TTSS). Two of the TTSSs are categorized as contact-dependent systems which have been shown in a number of different symbiotic and pathogenic bacteria to influence interactions with host organisms by targeting effector proteins into the cytosol of eukaryotic cells. The third TTSS is required for the assembly of flagella and the secretion of the phospholipase YplA, which has been implicated in Y. enterocolitica virulence. In this study, YplA was expressed from a constitutive promoter in strains that contained only a single TTSS. It was determined that each of the three TTSSs is individually sufficient for YplA secretion. Environmental factors such as temperature, calcium availability, and sodium chloride concentration affected the contribution of each system to extracellular protein secretion and, under some conditions, more than one TTSS appeared to operate simultaneously. This suggests that some proteins might normally be exported by more than one TTSS in Y. enterocolitca.

scholarly journals Tandem Translation Generates a Chaperone for the Salmonella Type III Secretion System Protein SsaQ

2011 ◽  
Vol 286 (41) ◽  
pp. 36098-36107 ◽  
Author(s):  
Xiu-Jun Yu ◽  
Mei Liu ◽  
Steve Matthews ◽  
David W. Holden
Keyword(s):  
Type Iii Secretion ◽  
Ex Vivo ◽  
Eukaryotic Cell ◽  
Effector Proteins ◽  
Secretion Systems ◽  
Type Iii ◽  
Type Iii Secretion Systems ◽  
Function Loss ◽  
Bacterial Cytoplasm

Type III secretion systems (T3SSs) of bacterial pathogens involve the assembly of a surface-localized needle complex, through which translocon proteins are secreted to form a pore in the eukaryotic cell membrane. This enables the transfer of effector proteins from the bacterial cytoplasm to the host cell. A structure known as the C-ring is thought to have a crucial role in secretion by acting as a cytoplasmic sorting platform at the base of the T3SS. Here, we studied SsaQ, an FliN-like putative C-ring protein of the Salmonella pathogenicity island 2 (SPI-2)-encoded T3SS. ssaQ produces two proteins by tandem translation: a long form (SsaQL) composed of 322 amino acids and a shorter protein (SsaQS) comprising the C-terminal 106 residues of SsaQL. SsaQL is essential for SPI-2 T3SS function. Loss of SsaQS impairs the function of the T3SS both ex vivo and in vivo. SsaQS binds to its corresponding region within SsaQL and stabilizes the larger protein. Therefore, SsaQL function is optimized by a novel chaperone-like protein, produced by tandem translation from its own mRNA species.

scholarly journals Type III secretion systems and the evolution of mutualistic endosymbiosis

2002 ◽  
Vol 99 (19) ◽  
pp. 12397-12402 ◽  
Author(s):  
C. Dale ◽  
G. R. Plague ◽  
B. Wang ◽  
H. Ochman ◽  
N. A. Moran
Keyword(s):  
Type Iii Secretion ◽  
Secretion Systems ◽  
Type Iii ◽  
Type Iii Secretion Systems
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