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Virginia L. Miller - One of the best experts on this subject based on the ideXlab platform.
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Yersinia enterocolitica Invasin-dependent and Invasin-independent mechanisms of systemic dissemination.
Infection and immunity, 2005Co-Authors: Scott A. Handley, Rodney D. Newberry, Virginia L. MillerAbstract:We report here Invasin-dependent and Invasin-independent mechanisms in which the enteropathogen Yersinia enterocolitica is able to disseminate from the lumen of the small intestine to the spleen. The Invasin-dependent route is clearly discernible in mice devoid of intestinal Peyer's patches and mesenteric lymph nodes.
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Invasin and beyond: regulation of Yersinia virulence by RovA.
Trends in microbiology, 2004Co-Authors: Damon W. Ellison, Matthew B. Lawrenz, Virginia L. MillerAbstract:Abstract RovA, a member of the MarR/SlyA family of winged-helix transcription factors, regulates expression of Invasin, the major adhesion and invasion factor in Yersinia enterocolitica and Yersinia pseudotuberculosis . Disruption of rovA increases the LD 50 of the organism when inoculated using the oral route. However, when administered by intraperitoneal injection only a slight difference in LD 50 between mutant and wild-type organisms is apparent. The study of RovA and the genes it regulates provides a unique opportunity to gain insight into the initial stages of a Yersinia infection.
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YmoA Negatively Regulates Expression of Invasin from Yersinia enterocolitica
Journal of bacteriology, 2003Co-Authors: Damon W. Ellison, Briana M. Young, Kristin M. Nelson, Virginia L. MillerAbstract:inv encodes Invasin, which is the primary invasion factor of Yersinia enterocolitica. inv expression in vitro is regulated in response to temperature, pH, and growth phase. In vitro, inv is maximally expressed at 26°C and repressed at 37°C at neutral pH but, when the pH of the media is adjusted to 5.5, levels of inv expression at 37°C are comparable to those at 26°C. A previous genetic screen for regulators of inv identified RovA, which was found to be required for activation of inv in vitro under all conditions tested as well as in vivo. Here we describe a screen that has identified a negative regulator of inv expression, ymoA. The ymoBA locus was identified by transposon mutagenesis as a repressor of inv expression in vitro at 37°C at neutral pH. This mutant shows increased inv expression at 37°C. The mutant can be fully complemented for inv expression by a plasmid expressing ymoA. These results indicate that YmoA plays a role in the negative regulation of inv.
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A chromosomally encoded regulator is required for expression of the Yersinia enterocolitica inv gene and for virulence
Molecular Microbiology, 2002Co-Authors: Paula A. Revell, Virginia L. MillerAbstract:: The primary invasion factor of Yersinia enterocolitica, Invasin, is encoded by inv. inv expression is regulated in response to pH, growth phase and temperature. In vitro, inv is maximally expressed at 26 degrees C, pH 8.0, or 37 degrees C, pH 5.5, in early stationary phase. At 37 degrees C, pH 8.0, inv is weakly expressed. To identify which gene(s) are required for inv regulation, we screened for transposon insertions that decreased expression of an inv-'phoA chromosomal reporter at 26 degrees C. Of 30 000 mutants screened, two were identified that had negligible inv expression in all conditions tested. Both of these independent mutants had an insertion into the same gene, designated rovA (regulator of virulence). RovA has 77% amino acid identity to the Salmonella typhimurium transcriptional regulator SlyA. Complementation with the wild-type rovA allele restores wild-type inv expression as monitored by Western blot analysis, tissue culture invasion assay and alkaline phosphatase assay. There is also a significant decrease in Invasin levels in bacteria recovered from mice infected with the rovA mutant; therefore, RovA regulates inv expression in vivo as well as in vitro. In the mouse infection model, an inv mutant has a wild-type LD50, even though the kinetics of infection is changed. In contrast, the rovA mutant has altered kinetics, as well as a 70-fold increase in the LD50 compared with wild type. Furthermore, because the rovA mutant is attenuated in the mouse model, this suggests that RovA regulates other virulence factors in addition to inv. Analysis of other proposed virulence factors such as Ail, YadA and the Yop proteins shows no regulatory role for RovA. The more severe animal phenotype combined with the lack of impact on known virulence genes aside from inv suggests RovA regulates potentially novel virulence genes of Y. enterocolitica during infection.
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EXPRESSION OF Invasin AND MOTILITY ARE COORDINATELY REGULATED IN YERSINIA ENTEROCOLITICA
Journal of bacteriology, 1998Co-Authors: Julie L. Badger, Virginia L. MillerAbstract:The Yersinia enterocolitica inv gene encodes the primary invasion factor Invasin, which has been previously shown to be critical in the initial stages of infection. The expression of inv is influenced by growth phase and temperature and is maximal during late exponential-early stationary phase at 23°C. In addition, motility of Y. enterocolitica is regulated by temperature. Y. enterocolitica cells are motile when grown at lower temperatures (30°C or below), while bacteria grown at 37°C are nonmotile. This study was initiated to determine the molecular basis for the temperature regulation of inv expression. Two mutants were isolated that both showed a significant decrease in Invasin expression but are hypermotile when grown at 23°C. The first mutant (JB1A8v) was a result of a random mTn5Km insertion into the uvrC gene. The uvrC mutant JB1A8v demonstrated a significant decrease in inv and an increase in fleB (encodes flagellin) expression. These results suggest that expression of inv and flagellin genes is coordinated at the level of transcription. The second regulatory mutant, JB16v, was a result of a targeted insertion into a locus similar to sspA which in E. coli encodes a stationary-phase regulator. The E. coli sspA gene was cloned and assayed for complementation in both of the regulatory mutants. It was determined that E. coli sspA restored Invasin expression in both the uvrC mutant and the sspA mutant. In addition, the complementing clone decreased flagellin levels in these mutants.
Petra Dersch - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Hypoxia Decreases Invasin-Mediated Yersinia enterocolitica Internalization into Caco-2
2016Co-Authors: Nathalie E. Zeitouni, Petra Dersch, Hassan Y. Naim, Maren Von Köckritz-blickwedeAbstract:Yersinia enterocolitica is a major cause of human yersiniosis, with enterocolitis being a typi-cal manifestation. These bacteria can cross the intestinal mucosa, and invade eukaryotic cells by binding to host β1 integrins, a process mediated by the bacterial effector protein Invasin. This study examines the role of hypoxia on the internalization of Y. enterocolitica into intestinal epithelial cells, since the gastrointestinal tract has been shown to be physio-logically deficient in oxygen levels (hypoxic), especially in cases of infection and inflamma-tion. We show that hypoxic pre-incubation of Caco-2 cells resulted in significantly decreased bacterial internalization compared to cells grown under normoxia. This pheno-type was absent after functionally blocking host β1 integrins as well as upon infection with an Invasin-deficient Y. enterocolitica strain. Furthermore, downstream phosphorylation of the focal adhesion kinase was also reduced under hypoxia after infection. In good correla-tion to these data, cells grown under hypoxia showed decreased protein levels of β1 integ-rins at the apical cell surface whereas the total protein level of the hypoxia inducible factor (HIF-1) alpha was elevated. Furthermore, treatment of cells with the HIF-1 α stabilizer dimethyloxalylglycine (DMOG) also reduced invasion and decreased β1 integrin protein lev-els compared to control cells, indicating a potential role for HIF-1α in this process. These results suggest that hypoxia decreases Invasin-integrin-mediated internalization of Y. enter-ocolitica into intestinal epithelial cells by reducing cell surface localization of host β1 integrins
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Hypoxia Decreases Invasin-Mediated Yersinia enterocolitica Internalization into Caco-2 Cells
PloS one, 2016Co-Authors: Nathalie E. Zeitouni, Petra Dersch, Hassan Y. Naim, Maren Von Köckritz-blickwedeAbstract:Yersinia enterocolitica is a major cause of human yersiniosis, with enterocolitis being a typical manifestation. These bacteria can cross the intestinal mucosa, and invade eukaryotic cells by binding to host β1 integrins, a process mediated by the bacterial effector protein Invasin. This study examines the role of hypoxia on the internalization of Y. enterocolitica into intestinal epithelial cells, since the gastrointestinal tract has been shown to be physiologically deficient in oxygen levels (hypoxic), especially in cases of infection and inflammation. We show that hypoxic pre-incubation of Caco-2 cells resulted in significantly decreased bacterial internalization compared to cells grown under normoxia. This phenotype was absent after functionally blocking host β1 integrins as well as upon infection with an Invasin-deficient Y. enterocolitica strain. Furthermore, downstream phosphorylation of the focal adhesion kinase was also reduced under hypoxia after infection. In good correlation to these data, cells grown under hypoxia showed decreased protein levels of β1 integrins at the apical cell surface whereas the total protein level of the hypoxia inducible factor (HIF-1) alpha was elevated. Furthermore, treatment of cells with the HIF-1 α stabilizer dimethyloxalylglycine (DMOG) also reduced invasion and decreased β1 integrin protein levels compared to control cells, indicating a potential role for HIF-1α in this process. These results suggest that hypoxia decreases Invasin-integrin-mediated internalization of Y. enterocolitica into intestinal epithelial cells by reducing cell surface localization of host β1 integrins.
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Bacteriomimetic Invasin-functionalized nanocarriers for intracellular delivery.
Journal of controlled release : official journal of the Controlled Release Society, 2015Co-Authors: Hagar I. Labouta, Petra Dersch, Sara Menina, Annika Kochut, Sarah Gordon, Rebecca Geyer, Claus-michael LehrAbstract:Intracellular bacteria invade mammalian cells to establish an infectious niche. The current work models adhesion and subsequent internalization strategy of pathogenic bacteria into mammalian cells to design a bacteriomimetic bioinvasive delivery system. We report on the surface functionalization of liposomes with a C-terminal fragment of Invasin (InvA497), an invasion factor in the outer membrane of Yersinia pseudotuberculosis. InvA497-functionalized liposomes adhere to mammalian epithelial HEp-2 cell line at different infection stages with a significantly higher efficiency than liposomes functionalized with bovine serum albumin. Covalent attachment of InvA497 results in higher cellular adhesion than liposomes with physically adsorbed InvA497 with non-specific surface protein alignment. Uptake studies in HEp-2 cells indicate active internalization of InvA497-functionalized liposomes via β1-integrin receptor-mediated uptake mechanism mimicking the natural invasion strategy of Y. pseudotuberculosis. Uptake studies in Caco-2 cells at different polarization states demonstrate specific targeting of the InvA497-functionalized liposomes to less polarized cells reflecting the status of inflamed cells. Moreover, when loaded with the anti-infective agent gentamicin and applied to HEp-2 cells infected with Y. pseudotuberculosis, InvA497-functionalized liposomes are able to significantly reduce the infection load relative to non-functionalized drug-loaded liposomes. This indicates a promising application of such a bacteriomimetic system for drug delivery to intracellular compartments.
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Cell invasion of Yersinia pseudotuberculosis by Invasin and YadA requires protein kinase C, phospholipase C-gamma1 and Akt kinase.
Cellular Microbiology, 2009Co-Authors: Frank Uliczka, Tina Kornprobst, Julia Eitel, Daniela I. Schneider, Petra DerschAbstract:The outer membrane proteins YadA and Invasin of Yersinia pseudotuberculosis promote invasion into mammalian cells through beta(1)-integrins and trigger the production of interleukin (IL)-8. FAK, c-Src and the PI3 kinase were previously found to be important for both YadA- and Invasin-promoted uptake. Here, we demonstrate that two different downstream effectors of PI3 kinase, Akt and phospholipase Cgamma1 are required for efficient cell invasion. Inhibition of Akt or phospholipase C-gamma (PLC-gamma)1 by pharmaceutical agents as well as reduced expression of the isoforms Akt1 and Akt2, and of PLC-gamma1 by RNA interference decreased entry of YadA- and Inv-expressing bacteria significantly. In addition, we report that the conventional protein kinases C (PKC)alpha and -beta, positioned downstream of PLC-gamma1, are activated upon Inv- or YadA-promoted cell entry. They colocalize with intracellular bacteria and their depletion by siRNA treatment also resulted in a strong reduction of cell entry. In contrast, neither Akt nor PLC-gamma1, and the PKCs are essential for YadA- and Inv-mediated IL-8 synthesis and release. We conclude that YadA and Invasin of Y. pseudotuberculosis both trigger similar signal transduction pathways during integrin-mediated phagocytosis into epithelial cells, which lead to the activation of Akt, PLC-gamma1, PKCalpha and -beta downstream of PI3 kinase, separate from the MAPK-dependent pathway that triggers IL-8 production.
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the yada protein of yersinia pseudotuberculosis mediates high efficiency uptake into human cells under environmental conditions in which Invasin is repressed
Infection and Immunity, 2002Co-Authors: Julia Eitel, Petra DerschAbstract:The YadA protein is a major adhesin of Yersinia pseudotuberculosis that promotes tight adhesion to mammalian cells by binding to extracellular matrix proteins. In this study, we first addressed the possibility of competitive interference of YadA and the major invasive factor Invasin and found that expression of YadA in the presence of Invasin affected neither the export nor the function of Invasin in the outer membrane. Furthermore, expression of YadA promoted both bacterial adhesion and high-efficiency invasion entirely independently of Invasin. Antibodies against fibronectin and beta(1) integrins blocked invasion, indicating that invasion occurs via extracellular-matrix-dependent bridging between YadA and the host cell beta(1) integrin receptors. Inhibitor studies also demonstrated that tyrosine and Ser/Thr kinases, as well as phosphatidylinositol 3-kinase, are involved in the uptake process. Further expression studies revealed that yadA is regulated in response to several environmental parameters, including temperature, ion and nutrient concentrations, and the bacterial growth phase. In complex medium, YadA production was generally repressed but could be induced by addition of Mg(2+). Maximal expression of yadA was obtained in exponential-phase cells grown in minimal medium at 37 degrees C, conditions under which the Invasin gene is repressed. These results suggest that YadA of Y. pseudotuberculosis constitutes another independent high-level uptake pathway that might complement other cell entry mechanisms (e.g., Invasin) at certain sites or stages during the infection process.
Ralph R. Isberg - One of the best experts on this subject based on the ideXlab platform.
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An immunoglobulin superfamily-like domain unique to the Yersinia pseudotuberculosis Invasin protein is required for stimulation of bacterial uptake via integrin receptors.
Infection and immunity, 2000Co-Authors: Petra Dersch, Ralph R. IsbergAbstract:The binding of the Yersinia pseudotuberculosis and Yersinia enterocolitica Invasin proteins to β1 integrin receptors allows internalization of these organisms by cultured cells. The C-terminal 192-residue superdomain of the Y. pseudotuberculosis Invasin is necessary and sufficient for integrin recognition, while a region located outside, and N-terminal to, this superdomain strongly enhances the efficiency of bacterial uptake. Within the enhancer region is a domain called D2 that allows Invasin-Invasin interaction. To investigate the role of the enhancer region, bacterial cell binding and entry mediated by the Y. pseudotuberculosis Invasin protein (Invasinpstb) was compared to that of Y. enterocolitica Invasin (Invasinent), which lacks the D2 self-association domain. Invasinent was shown to be unable to promote self-interaction, using the DNA binding domain of λ repressor as a reporter. Furthermore, two genetically engineered in-frame deletion mutations that removed D2 from Invasinpstb were significantly less proficient than wild-type Invasinpstb at promoting uptake, although the amount of surface-exposed Invasin as well as the cell binding capacity of the recombinant Escherichia coli strains remained similar. Competitive uptake assays showed that E. coli cells expressing Invasinpstb had a significant advantage in the internalization process versus either E. coli cells expressing Invasinent or the Invasinpstb derivatives deleted for D2, further demonstrating the importance of Invasin self-interaction for the efficiency of Invasin-mediated uptake.
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Crystal Structure of Invasin: A Bacterial Integrin-Binding Protein
Science (New York N.Y.), 1999Co-Authors: Zsuzsa Andrea Hamburger, Ralph R. Isberg, Michele S. Brown, Pamela J. BjorkmanAbstract:The Yersinia pseudotuberculosis Invasin protein promotes bacterial entry by binding to host cell integrins with higher affinity than natural substrates such as fibronectin. The 2.3 angstrom crystal structure of the Invasin extracellular region reveals five domains that form a 180 angstrom rod with structural similarities to tandem fibronectin type III domains. The integrin-binding surfaces of Invasin and fibronectin include similarly located key residues, but in the context of different folds and surface shapes. The structures of Invasin and fibronectin provide an example of convergent evolution, in which Invasin presents an optimized surface for integrin binding, in comparison with host substrates.
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A region of the Yersinia pseudotuberculosis Invasin protein enhances integrin-mediated uptake into mammalian cells and promotes self-association
The EMBO journal, 1999Co-Authors: Petra Dersch, Ralph R. IsbergAbstract:Invasin allows efficient entry into mammalian cells by Yersinia pseudotuberculosis. It has been shown that the C-terminal 192 amino acids of Invasin are essential for binding of beta1 integrin receptors and subsequent uptake. By analyzing the internalization of latex beads coated with Invasin derivatives, an additional domain of Invasin was shown to be required for efficient bacterial internalization. A monomeric derivative encompassing the C-terminal 197 amino acids was inefficient at promoting entry of latex beads, whereas dimerization of this derivative by antibody significantly increased uptake. By using the DNA-binding domain of lambda repressor as a reporter for Invasin self-interaction, we have demonstrated that a region of the Invasin protein located N-terminal to the cell adhesion domain of Invasin is able to self-associate. Chemical cross-linking studies of purified and surface-exposed Invasin proteins, and the dominant-interfering effect of a non-functional Invasin derivative are consistent with the presence of a self-association domain that is located within the region of Invasin that enhances bacterial uptake. We conclude that interaction of homomultimeric Invasin with multiple integrins establishes tight adherence and receptor clustering, thus providing a signal for internalization.
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An aspartate residue of the Yersinia pseudotuberculosis Invasin protein that is critical for integrin binding.
The EMBO journal, 1995Co-Authors: John M. Leong, Paul E. Morrissey, A. Marra, Ralph R. IsbergAbstract:Abstract The Yersinia pseudotuberculosis Invasin protein mediates bacterial entry into mammalian cells by binding multiple beta 1-chain integrins. Invasin binding to purified alpha 5 beta 1 integrin is inhibited by Arg-Gly-Asp (RGD)-containing peptides, although Invasin contains no RGD sequence. Fifteen mutations that diminished binding and bacterial entry were isolated after mutagenesis of the entire inv gene. All of the mutations altered residues within the C-terminal 192 amino acids of Invasin, previously delineated as the integrin binding domain, and 10 of the mutations fell within an 11 residue region. This small region was subjected to site-directed mutagenesis and almost half of the 35 mutations generated decreased Invasin-mediated entry. D911 within this region was the most critical residue, as even a conservative glutamate substitution abolished bacterial penetration. Purified Invasin derivatives altered at this residue were defective in promoting cell attachment and this defect was reflected in a 10-fold or greater increase in IC50 for integrin binding. D911 may have a function similar to that of the aspartate residue in RGD-containing sequences.
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USE OF STAPHYLOCOCCUS AUREUS COATED WITH Invasin DERIVATIVES TO ASSAY Invasin FUNCTION
Methods in enzymology, 1994Co-Authors: Susannah Rankin, G. Tran Van Nhieu, Ralph R. IsbergAbstract:Publisher Summary This chapter reveals that the genetic analysis of outer membrane protein function in gram-negative bacteria may be hampered by the inability to achieve proper localization of potentially informative mutant proteins. The technique described allows functional analysis of an outer membrane protein with mutant derivatives, which cannot be properly expressed on the cell surface. The proteins are purified and subsequently attached to the bacterial cell surface, which allows easy manipulation of the final protein coating concentration. The technique is therefore particularly useful in studying the relative ability of a surface-exposed protein that mediates binding to and uptake by eukaryotic cells. The apparent obstacles to this genetic analysis, and the availability of the maltose-binding protein (MBP)-Invasin hybrid proteins, led to the design of a new protocol for the analysis of Invasin function. By attaching MBP-Inv hybrid proteins to the surface of Staphylococcus aureus , an organism that is not ordinarily able to enter mammalian cells, it is possible to test various C-terminal fragments of Invasin for their ability to mediate bacterial uptake using the previously standardized gentamicin protection assay. This approach could be broadly applicable in the analysis of potential adhesins or Invasins from a wide range of unrelated organisms.
Susan C. Straley - One of the best experts on this subject based on the ideXlab platform.
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yadBC of Yersinia pestis, a New Virulence Determinant for Bubonic Plague
Infection and Immunity, 2007Co-Authors: Stanislav Forman, Christine R. Wulff, Tanya Myers-morales, Clarissa Cowan, Robert D. Perry, Susan C. StraleyAbstract:In all Yersinia pestis strains examined, the adhesin/Invasin yadA gene is a pseudogene, yet Y. pestis is invasive for epithelial cells. To identify potential surface proteins that are structurally and functionally similar to YadA, we searched the Y. pestis genome for open reading frames with homology to yadA and found three: the bicistronic operon yadBC (YPO1387 and YPO1388 of Y. pestis CO92; y2786 and y2785 of Y. pestis KIM5), which encodes two putative surface proteins, and YPO0902, which lacks a signal sequence and likely is nonfunctional. In this study we characterized yadBC regulation and tested the importance of this operon for Y. pestis adherence, invasion, and virulence. We found that loss of yadBC caused a modest loss of invasiveness for epithelioid cells and a large decrease in virulence for bubonic plague but not for pneumonic plague in mice.
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invasion of epithelial cells by yersinia pestis evidence for a y pestis specific Invasin
Infection and Immunity, 2000Co-Authors: Clarissa Cowan, Robert D. Perry, Heather A Jones, Yasemin H Kaya, Susan C. StraleyAbstract:The causative agent of plague, Yersinia pestis, is regarded as being noninvasive for epithelial cells and lacks the major adhesins and Invasins of its enteropathogenic relatives Yersinia enterocolitica and Yersinia pseudotuberculosis. However, there are studies indicating that Y. pestis invades and causes systemic infection from ingestive and aerogenic routes of infection. Accordingly, we developed a gentamicin protection assay and reexamined invasiveness of Y. pestis for HeLa cells. By optimizing this assay, we discovered that Y. pestis is highly invasive. Several factors, including the presence of fetal bovine serum, the configuration of the tissue culture plate, the temperature at which the bacteria are grown, and the presence of the plasminogen activator protease Pla-encoding plasmid pPCP1, were found to influence invasiveness strongly. Suboptimal combinations of these factors may have contributed to negative findings by previous studies attempting to demonstrate invasion by Y. pestis. Invasion of HeLa cells was strongly inhibited by cytochalasin D and modestly inhibited by colchicine, indicating strong and modest respective requirements for microfilaments and microtubules. We found no significant effect of the iron status of yersiniae or of the pigmentation locus on invasion and likewise no significant effect of the Yops regulon. However, an unidentified thermally induced property (possibly the Y. pestis-specific capsular protein Caf1) did inhibit invasiveness significantly, and the plasmid pPCP1, unique to Y. pestis, was essential for highly efficient invasion. pPCP1 encodes an invasion-promoting factor and not just an adhesin, because Y. pestis lacking this plasmid still adhered to HeLa cells. These studies have enlarged our picture of Y. pestis biology and revealed the importance of properties that are unique to Y. pestis.
Manfred Rohde - One of the best experts on this subject based on the ideXlab platform.
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Unique Cell Adhesion and Invasion Properties of Yersinia enterocolitica O:3, the Most Frequent Cause of Human
2015Co-Authors: Frank Uliczka, Manfred Rohde, Fabio Pisano, Julia Schaake, Tatjana Stolz, Angelika Fruth, Eckhard Strauch, Mikael Skurnik, Julia Batzilla, Er RakinAbstract:Many enteric pathogens are equipped with multiple cell adhesion factors which are important for host tissue colonization and virulence. Y. enterocolitica, a common food-borne pathogen with invasive properties, uses the surface proteins Invasin and YadA for host cell binding and entry. In this study, we demonstrate unique cell adhesion and invasion properties of Y. enterocolitica serotype O:3 strains, the most frequent cause of human yersiniosis, and show that these differences are mainly attributable to variations affecting the function and expression of Invasin in response to temperature. In contrast to other enteric Yersinia strains, Invasin production in O:3 strains is constitutive and largely enhanced compared to other Y. enterocolitica serotypes, in which invA expression is temperature-regulated and significantly reduced at 37uC. Increase of Invasin levels is caused by (i) an IS1667 insertion into the invA promoter region, which includes an additional promoter and RovA and H-NS binding sites, and (ii) a P98S substitution in the invA activator protein RovA rendering the regulator less susceptible to proteolysis. Both variations were shown to influence bacterial colonization in a murine infection model. Furthermore, we found that co-expression of YadA and down-regulation of the O-antigen at 37uC is required to allow efficient internalization by the InvA protein. We conclude that even small variations in the expression of virulence factor
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the fbab type fibronectin binding protein of streptococcus pyogenes promotes specific invasion into endothelial cells
Cellular Microbiology, 2011Co-Authors: Silva Amelung, Jason N Cole, Barbara Spellerberg, Victor Nizet, Andreas Nerlich, Gursharan S. Chhatwal, Manfred Rohde, Susanne R TalayAbstract:Invasive serotype M3 Streptococcus pyogenes are among the most frequently isolated organisms from patients suffering from invasive streptococcal disease and have the potential to invade primary human endothelial cells (EC) via a rapid and efficient mechanism. FbaB protein, the fibronectin-binding protein expressed by M3 S. pyogenes, was herein identified as a potent Invasin for EC. By combining heterologous gene expression with allelic replacement, we demonstrate that FbaB is essential and sufficient to trigger EC invasion via a Rac1-dependent phagocytosis-like uptake. FbaB-mediated uptake follows the classical endocytic pathway with lysosomal destination. FbaB is demonstrated to be a streptococcal Invasin exhibiting EC tropism. FbaB thus initiates a process that may contribute to the deep tissue tropism and spread of invasive S. pyogenes isolates into the vascular EC lining.
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differences in the aromatic domain of homologous streptococcal fibronectin binding proteins trigger different cell invasion mechanisms and survival rates
Cellular Microbiology, 2011Co-Authors: Manfred Rohde, Patricia Borchers, Claudia Preuss, Ina Schleicher, Dorothea Zahner, Rikki M.a. Graham, Marcus Fulde, Susanne R Talay, Katja Branitzkiheinemann, Katrin DinklaAbstract:Summary Group A streptococci (GAS, Streptococcus pyo- genes) and Group G streptococci (GGS, Strepto- coccus dysgalactiae ssp. equisimilis) adhere to and invade host cells by binding to fibronectin. The fibronectin-binding protein SfbI from GAS acts as an Invasin by using a caveolae-mediated mechanism. In the present study we have identi- fied a fibronectin-binding protein, GfbA, from GGS, which functions as an adhesin and Invasin. Although there is a high degree of similarity in the C-terminal sequence of SfbI and GfbA, the invasion mechanisms are different. Unlike caveolae-mediated invasion by SfbI-expressing GAS, the GfbA-expressing GGS isolate trigger cytoskeleton rearrangements. Heterologous ex- pression of GfbA on the surface of a commensal Streptococcus gordonii and purified recombinant protein also triggered actin rearrangements. Expression of a truncated GfbA (lacking the aro- matic domain) and chimeric GfbA/SfbI protein (replacing the aromatic domain of SfbI with the GfbA aromatic domain) on S. gordonii or recombi- nant proteins alone showed that the aromatic domain of GfbA is responsible for different inva- sion mechanisms. This is the first evidence for a biological function of the aromatic domain of fibronectin-binding proteins. Furthermore, we show that streptococci invading via cytoskeleton rearrangements and intracellular trafficking along the classical endocytic pathway are less persis- tence than streptococci entering via caveolae.
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Differences in the aromatic domain of homologous streptococcal fibronectin‐binding proteins trigger different cell invasion mechanisms and survival rates
Cellular Microbiology, 2010Co-Authors: Manfred Rohde, Katja Branitzki-heinemann, Patricia Borchers, Claudia Preuss, Ina Schleicher, Dorothea Zahner, Rikki M.a. Graham, Marcus Fulde, Susanne R Talay, Katrin DinklaAbstract:Summary Group A streptococci (GAS, Streptococcus pyo- genes) and Group G streptococci (GGS, Strepto- coccus dysgalactiae ssp. equisimilis) adhere to and invade host cells by binding to fibronectin. The fibronectin-binding protein SfbI from GAS acts as an Invasin by using a caveolae-mediated mechanism. In the present study we have identi- fied a fibronectin-binding protein, GfbA, from GGS, which functions as an adhesin and Invasin. Although there is a high degree of similarity in the C-terminal sequence of SfbI and GfbA, the invasion mechanisms are different. Unlike caveolae-mediated invasion by SfbI-expressing GAS, the GfbA-expressing GGS isolate trigger cytoskeleton rearrangements. Heterologous ex- pression of GfbA on the surface of a commensal Streptococcus gordonii and purified recombinant protein also triggered actin rearrangements. Expression of a truncated GfbA (lacking the aro- matic domain) and chimeric GfbA/SfbI protein (replacing the aromatic domain of SfbI with the GfbA aromatic domain) on S. gordonii or recombi- nant proteins alone showed that the aromatic domain of GfbA is responsible for different inva- sion mechanisms. This is the first evidence for a biological function of the aromatic domain of fibronectin-binding proteins. Furthermore, we show that streptococci invading via cytoskeleton rearrangements and intracellular trafficking along the classical endocytic pathway are less persis- tence than streptococci entering via caveolae.
