Assembly of the <i>Yersinia</i> injectisome: the missing pieces

Diepold, Andreas; Wiesand, Ulrich; Amstutz, Marlise; Cornelis, Guy R.

doi:10.1111/j.1365-2958.2012.08146.x

Cited by 59 publications

(92 citation statements)

References 99 publications

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“…Both functional and nonfunctional YscO mutant proteins were found intrabacterially but not in the secreted fraction. This was also the case for wild-type YscO, in contrast to data reported for Y. pestis and Y. enterocolitica (3,4). Likewise, both functional and nonfunctional YscO mutant proteins interacted with SycD, suggesting that the mutations had not affected the structure or stability of YscO.…”

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confidence: 55%

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Functionally Essential Interaction between Yersinia YscO and the T3S4 Domain of YscP

Mukerjea

Ghosh

2013

J Bacteriol

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The type III secretion (T3S) system is essential to the virulence of a large number of Gram-negative bacterial pathogens, including Yersinia. YscO is required for T3S in Yersinia and is known to interact with several other T3S proteins, including the chaperone SycD and the needle length regulator YscP. To define which interactions of YscO are required for T3S, we pursued modelguided mutagenesis: three conserved and surface-exposed regions of modeled YscO were targeted for multiple alanine substitutions. Most of the mutations abrogated T3S and did so in a recessive manner, consistent with a loss of function. Both functional and nonfunctional YscO mutant proteins interacted with SycD, indicating that the mutations had not affected protein stability. Likewise, both functional and nonfunctional versions of YscO were exclusively intrabacterial. Functional and nonfunctional versions of YscO were, however, distinguishable with respect to interaction with YscP. This interaction was observed only for wild-type YscO and a T3S-proficient mutant of YscO but not for the several T3S-deficient mutants of YscO. Evidence is presented that the YscO-YscP interaction is direct and that the type III secretion substrate specificity switch (T3S4) domain of YscP is sufficient for this interaction. These results provide evidence that the interaction of YscO with YscP, and in particular the T3S4 domain of YscP, is essential to type III secretion.

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confidence: 55%

“…This small peripheral membrane-associated protein localizes to the inner bacterial membrane and the cytosol (3). YscO has also been reported to be secreted by Yersinia pestis and Yersinia enterocolitica (3,4). While YscO is essential for type III secretion (3), the basis for its essentiality is unknown.…”

mentioning

confidence: 99%

Functionally Essential Interaction between Yersinia YscO and the T3S4 Domain of YscP

Mukerjea

Ghosh

2013

J Bacteriol

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“…However, 12 genes showed Ͼ4-fold changes in expression when comparing intracellular bacteria to extracellular bacteria, including 4 genes that are upregulated and 8 that are downregulated. Interestingly, two of the most highly downregulated genes, yscO and yscQ, encode proteins that make up critical components of the Ysc T3SS (66), suggesting that the system has decreased importance within the YCV. Table S6 in the supplemental material shows the expression of all of the genes on the virulence plasmid, demonstrating that there is a general trend toward reduced expression of Ysc genes in response to internalization.…”

Section: Resultsmentioning

confidence: 99%

Transcriptomic Analysis of Yersinia enterocolitica Biovar 1B Infecting Murine Macrophages Reveals New Mechanisms of Extracellular and Intracellular Survival

et al. 2015

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c Yersinia enterocolitica is typically considered an extracellular pathogen; however, during the course of an infection, a significant number of bacteria are stably maintained within host cell vacuoles. Little is known about this population and the role it plays during an infection. To address this question and to elucidate the spatially and temporally dynamic gene expression patterns of Y. enterocolitica biovar 1B through the course of an in vitro infection, transcriptome sequencing and differential gene expression analysis of bacteria infecting murine macrophage cells were performed under four distinct conditions. Bacteria were first grown in a nutrient-rich medium at 26°C to establish a baseline of gene expression that is unrelated to infection. The transcriptomes of these bacteria were then compared to bacteria grown in a conditioned cell culture medium at 37°C to identify genes that were differentially expressed in response to the increased temperature and medium but not in response to host cells. Infections were then performed, and the transcriptomes of bacteria found on the extracellular surface and intracellular compartments were analyzed individually. The upregulated genes revealed potential roles for a variety of systems in promoting intracellular virulence, including the Ysa type III secretion system, the Yts2 type II secretion system, and the Tad pilus. It was further determined that mutants of each of these systems had decreased virulence while infecting macrophages. Overall, these results reveal the complete set of genes expressed by Y. enterocolitica in response to infection and provide the groundwork for future virulence studies.T he genus Yersinia includes three species that are pathogenic to humans: Y. pestis, the causative agent of the plague, as well as Y. enterocolitica and Y. pseudotuberculosis, both of which cause gastrointestinal diseases. Of the three organisms, Y. enterocolitica is the species most frequently isolated from humans (1). Y. enterocolitica infections are typically acquired through ingestion of the bacteria in contaminated food or water, especially raw or undercooked pork products (2). After ingestion, the bacteria travel through the gastrointestinal tract to the terminal ileum, where they are able to penetrate the M cells of the Peyer's patches and infect the mesenteric lymph nodes (1-3). This leads to a self-limiting gastroenteritis and mesenteric lymphadenitis in otherwise healthy patients (3). In immunocompromised patients or young children with developing immune systems, the bacteria can spread from the lymph nodes to systemic sites, leading to potentially fatal septicemia (1). Over half of all reported Y. enterocolitica infections occur in children under the age of five, the group that is most predisposed to developing the systemic form of the infection (4).Pathogenic Y. enterocolitica isolates can be divided into six distinct biovars based on several biochemical and physiological attributes (2, 5). Of the six biovars, the North American isolate, biovar 1B, is the most...

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“…Independently, the export apparatus can assemble within the IM [114,134]. After the concurrent assembly of the cytosolic complex, requiring all of its components SctN, SctL, SctQ and SctL (but not the stalk SctO), the T3SS is functional and the needle can be formed [113,135].…”

Section: Transcription Hierarchy Assembly and Activation Of The T3ssmentioning

confidence: 99%

Type III secretion systems: the bacterial flagellum and the injectisome

Diepold

Armitage

2015

Phil. Trans. R. Soc. B

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183

175

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One contribution of 12 to a theme issue 'The bacterial cell envelope'. The flagellum and the injectisome are two of the most complex and fascinating bacterial nanomachines. At their core, they share a type III secretion system (T3SS), a transmembrane export complex that forms the extracellular appendages, the flagellar filament and the injectisome needle. Recent advances, combining structural biology, cryo-electron tomography, molecular genetics, in vivo imaging, bioinformatics and biophysics, have greatly increased our understanding of the T3SS, especially the structure of its transmembrane and cytosolic components, the transcriptional, post-transcriptional and functional regulation and the remarkable adaptivity of the system. This review aims to integrate these new findings into our current knowledge of the evolution, function, regulation and dynamics of the T3SS, and to highlight commonalities and differences between the two systems, as well as their potential applications.

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Assembly of the Yersinia injectisome: the missing pieces

Cited by 59 publications

References 99 publications

Functionally Essential Interaction between Yersinia YscO and the T3S4 Domain of YscP

Functionally Essential Interaction between Yersinia YscO and the T3S4 Domain of YscP

Transcriptomic Analysis of Yersinia enterocolitica Biovar 1B Infecting Murine Macrophages Reveals New Mechanisms of Extracellular and Intracellular Survival

Type III secretion systems: the bacterial flagellum and the injectisome

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