scholarly journals Campylobacter jejuni Triggers Signaling through Host Cell Focal Adhesions To Inhibit Cell Motility

mBio ◽  
2021 ◽  
Author(s):  
Courtney M. Klappenbach ◽  
Nicholas M. Negretti ◽  
Jesse Aaron ◽  
Teng-Leong Chew ◽  
Michael E. Konkel
Keyword(s):  
Epithelial Cells ◽  
Cell Motility ◽  
Host Cell ◽  
Campylobacter Jejuni ◽  
Focal Adhesion ◽  
Foodborne Pathogen ◽  
Focal Adhesions ◽  
Structure And Function ◽  
Content Type ◽  
And Function

Campylobacter jejuni is a major foodborne pathogen that causes severe gastritis. We investigated the dynamics of focal adhesion structure and function in C. jejuni -infected epithelial cells.

scholarly journals The Campylobacter jejuni CadF and FlpA fibronectin binding proteins facilitate signaling via host cell focal adhesions to inhibit cell motility and impede wound repair

2021 ◽  
Author(s):  
Courtney M Klappenbach ◽  
Nicholas M Negretti ◽  
Jesse Aaron ◽  
Teng-Leong Chew ◽  
Michael E Konkel
Keyword(s):  
Extracellular Matrix ◽  
Cell Motility ◽  
Host Cell ◽  
Campylobacter Jejuni ◽  
Focal Adhesion ◽  
Binding Proteins ◽  
Focal Adhesions ◽  
Cell Behavior ◽  
Extracellular Matrix Components ◽  
Fibronectin Binding

Campylobacter jejuni is a major foodborne pathogen that exploits the focal adhesions of intestinal cells to promote invasion and cause severe gastritis. Focal adhesions are multiprotein complexes involved in bidirectional signaling between the actin cytoskeleton and the extracellular matrix. We investigated the dynamics of focal adhesion structure and function in C. jejuni infected cells. We found that C. jejuni infection of epithelial cells results in an increased focal adhesion size, enhanced signaling, and altered topology, as demonstrated by confocal microscopy, immunoblots, and super-resolution iPALM. Infection by C. jejuni also resulted in an increase in cell adhesion strength, reduced host cell motility, and reduction of collective host cell migration, a fundamental step in intestinal villi healing. Mechanistic studies demonstrated that the C. jejuni fibronectin-binding proteins CadF and FlpA are involved in the changes in focal adhesion dynamics and alterations in cell behavior. These findings are important because they provide a putative mechanistic basis for the restricted intestinal repair observed in C. jejuni-infected animals and raise the possibility that bacterial adhesins that target extracellular matrix components can alter cell behavior by manipulating focal adhesions.

scholarly journals The Campylobacter jejuni CiaD effector co-opts the host cell protein IQGAP1 to promote cell entry

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nicholas M. Negretti ◽  
Christopher R. Gourley ◽  
Prabhat K. Talukdar ◽  
Geremy Clair ◽  
Courtney M. Klappenbach ◽  
...  
Keyword(s):  
Host Cell ◽  
Campylobacter Jejuni ◽  
Foodborne Pathogen ◽  
Small Gtpase ◽  
Host Cells ◽  
Cell Protein ◽  
Host Cell Protein ◽  
Cell Binding ◽  
Actin Reorganization ◽  
Cell Cytosol

AbstractCampylobacter jejuni is a foodborne pathogen that binds to and invades the epithelial cells lining the human intestinal tract. Maximal invasion of host cells by C. jejuni requires cell binding as well as delivery of the Cia proteins (Campylobacter invasion antigens) to the host cell cytosol via the flagellum. Here, we show that CiaD binds to the host cell protein IQGAP1 (a Ras GTPase-activating-like protein), thus displacing RacGAP1 from the IQGAP1 complex. This, in turn, leads to the unconstrained activity of the small GTPase Rac1, which is known to have roles in actin reorganization and internalization of C. jejuni. Our results represent the identification of a host cell protein targeted by a flagellar secreted effector protein and demonstrate that C. jejuni-stimulated Rac signaling is dependent on IQGAP1.

scholarly journals A Cronobacter turicensis O1 Antigen-Specific Monoclonal Antibody Inhibits Bacterial Motility and Entry into Epithelial Cells

2014 ◽  
Vol 83 (3) ◽  
pp. 876-887 ◽  
Author(s):  
Kristina Schauer ◽  
Angelika Lehner ◽  
Richard Dietrich ◽  
Ina Kleinsteuber ◽  
Rocío Canals ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Epithelial Cells ◽  
Foodborne Pathogen ◽  
Antimicrobial Effect ◽  
Infection Model ◽  
Cell Agglutination ◽  
Content Type ◽  
O Antigen ◽  
Lethal Infection ◽  
Insight Into

Cronobacter turicensisis an opportunistic foodborne pathogen that can cause a rare but sometimes lethal infection in neonates. Little is known about the virulence mechanisms and intracellular lifestyle of this pathogen. In this study, we developed an IgG monoclonal antibody (MAb; MAb 2G4) that specifically recognizes the O1 antigen ofC. turicensiscells. The antilipopolysaccharide antibody bound predominantly monovalently to the O antigen and reduced bacterial growth without causing cell agglutination. Furthermore, binding of the antibody to the O1 antigen ofC. turicensiscells caused a significant reduction of the membrane potential which is required to energize flagellar rotation, accompanied by a decreased flagellum-based motility. These results indicate that binding of IgG to the O antigen ofC. turicensiscauses a direct antimicrobial effect. In addition, this feature of the antibody enabled new insight into the pathogenicity ofC. turicensis. In a tissue culture infection model, pretreatment ofC. turicensiswith MAb 2G4 showed no difference in adhesion to human epithelial cells, whereas invasion of bacteria into Caco-2 cells was significantly inhibited.

Reflections on team culture, structure and function of an intensive support service centred on positive behavioural support

2016 ◽  
Vol 21 (4) ◽  
pp. 203-211 ◽  
Author(s):  
Lawrence A. Patterson ◽  
Samuel Berry
Keyword(s):  
Social Services ◽  
Support Service ◽  
Structure And Function ◽  
Content Type ◽  
Case Examples ◽  
Behavioural Support ◽  
Team Culture ◽  
Shared Identity ◽  
The Right ◽  
And Function

Purpose The purpose of this paper is to explore experiences of team culture, structure and function of an intensive support service (ISS) within the context of the recent service guidance “Building the Right Support” (NHS England, Local Government Association and Association of Directors of Adult Social Services, 2015). Reflections on the Hampshire and Southampton ISS set up in 2010 are discussed with a view to informing a debate about frameworks for ISS services nationally. Design/methodology/approach A reflective piece, drawing on experience and case examples. Findings This paper describes that a key function of an ISS is making individuals safe and this is significantly assisted by using shared team formulation, which can enable information and perspectives to be shared between and within teams as rapidly as possible. Further, a case is made for recognising the importance of inter-disciplinary practice, as the Southampton and Hampshire ISS has removed the “old fashioned” demarcations that led to individuals seeing a “procession” of different professionals from different disciplines. This relates to team structure, but importantly is about a culture of holding a shared identity based on positive behavioural support values, rather than a traditional uni-disciplinary perspective. Practical implications ISS models are being proposed by NHS England and this paper suggests some important practical aspects. Originality/value Limited literature exists examining the team culture within ISSs, which contributes to desired outcomes for service users. This paper opens a debate about structural and functional aspects of service delivery in this service model.

EGF receptor regulation of cell motility: EGF induces disassembly of focal adhesions independently of the motility-associated PLCgamma signaling pathway

1998 ◽  
Vol 111 (5) ◽  
pp. 615-624 ◽  
Author(s):  
H. Xie ◽  
M.A. Pallero ◽  
K. Gupta ◽  
P. Chang ◽  
M.F. Ware ◽  
...  
Keyword(s):  
Growth Factor ◽  
Cell Motility ◽  
Map Kinase ◽  
Signaling Pathway ◽  
Focal Adhesion ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Focal Adhesions ◽  
Short Term ◽  
Egfr Kinase

A current model of growth factor-induced cell motility invokes integration of diverse biophysical processes required for cell motility, including dynamic formation and disruption of cell/substratum attachments along with extension of membrane protrusions. To define how these biophysical events are actuated by biochemical signaling pathways, we investigate here whether epidermal growth factor (EGF) induces disruption of focal adhesions in fibroblasts. We find that EGF treatment of NR6 fibroblasts presenting full-length WT EGF receptors (EGFR) reduces the fraction of cells presenting focal adhesions from approximately 60% to approximately 30% within 10 minutes. The dose dependency of focal adhesion disassembly mirrors that for EGF-enhanced cell motility, being noted at 0.1 nM EGF. EGFR kinase activity is required as cells expressing two kinase-defective EGFR constructs retain their focal adhesions in the presence of EGF. The short-term (30 minutes) disassembly of focal adhesions is reflected in decreased adhesiveness of EGF-treated cells to substratum. We further examine here known motility-associated pathways to determine whether these contribute to EGF-induced effects. We have previously demonstrated that phospholipase C(gamma) (PLCgamma) activation and mobilization of gelsolin from a plasma membrane-bound state are required for EGFR-mediated cell motility. In contrast, we find here that short-term focal adhesion disassembly is induced by a signaling-restricted truncated EGFR (c'973) which fails to activate PLCgamma or mobilize gelsolin. The PLC inhibitor U73122 has no effect on this process, nor is the actin severing capacity of gelsolin required as EGF treatment reduces focal adhesions in gelsolin-devoid fibroblasts, further supporting the contention that focal adhesion disassembly is signaled by a pathway distinct from that involving PLCgamma. Because both WT and c'973 EGFR activate the erk MAP kinase pathway, we additionally explore here this signaling pathway, not previously associated with growth factor-induced cell motility. Levels of the MEK inhibitor PD98059 that block EGF-induced mitogenesis and MAP kinase phosphorylation also abrogate EGF-induced focal adhesion disassembly and cell motility. In summary, we characterize for the first time the ability of EGFR kinase activity to directly stimulate focal adhesion disassembly and cell/substratum detachment, in relation to its ability to stimulate migration. Furthermore, we propose a model of EGF-induced motogenic cell responses in which the PLCgamma pathway stimulating cell motility is distinct from the MAP kinase-dependent signaling pathway leading to disassembly and reorganization of cell-substratum adhesion.

scholarly journals Draft Genome Sequences of Multidrug-Resistant Campylobacter jejuni Strains Isolated from Chickens in Central China

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Yiluo Cheng ◽  
Wenting Zhang ◽  
Qin Lu ◽  
Guoyuan Wen ◽  
Qingping Luo ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Antimicrobial Resistance ◽  
Campylobacter Jejuni ◽  
Draft Genome ◽  
Foodborne Pathogen ◽  
Multidrug Resistant ◽  
Central China ◽  
Genome Sequences ◽  
Genetic Characteristics ◽  
Content Type

Campylobacter jejuni is a major foodborne pathogen that plays an important role in spreading drug resistance. We report the draft genome sequences of two multidrug-resistant C. jejuni isolates which contained similar mutations in the CmeR box. This will improve the understanding of C. jejuni antimicrobial resistance and genetic characteristics.

scholarly journals Genetics behind the Biosynthesis of Nonulosonic Acid-Containing Lipooligosaccharides inCampylobacter coli

2019 ◽  
Vol 201 (8) ◽  
Author(s):  
Alejandra Kolehmainen ◽  
Mirko Rossi ◽  
Jacek Stupak ◽  
Jianjun Li ◽  
Michel Gilbert ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Foodborne Pathogen ◽  
Campylobacter Coli ◽  
Strong Impact ◽  
Large Set ◽  
Content Type ◽  
Donor And Acceptor ◽  
Nonulosonic Acid ◽  
Acute Polyneuropathy

ABSTRACTCampylobacter jejuniandCampylobacter coliare the most common causes of bacterial gastroenteritis in the world. Ganglioside mimicry byC. jejunilipooligosaccharide (LOS) is the triggering factor of Guillain-Barré syndrome (GBS), an acute polyneuropathy. Sialyltransferases from glycosyltransferase family 42 (GT-42) are essential for the expression of ganglioside mimics inC. jejuni. Recently, two novel GT-42 genes,cstIVandcstV, have been identified inC. coli. Despite being present in ∼11% of currently availableC. coligenomes, the biological role ofcstIVandcstVis unknown. In the present investigation, mutation studies with two strains expressing eithercstIVorcstVwere performed and mass spectrometry was used to investigate differences in the chemical composition of LOS. Attempts were made to identify donor and acceptor molecules usingin vitroactivity tests with recombinant GT-42 enzymes. Here we show that CstIV and CstV are involved inC. coliLOS biosynthesis. In particular,cstVis associated with LOS sialylation, whilecstIVis linked to the addition of a diacetylated nonulosonic acid residue.IMPORTANCEDespite the fact thatCampylobacter colia major foodborne pathogen, its glycobiology has been largely neglected. The genetic makeup of theC. colilipooligosaccharide biosynthesis locus was largely unknown until recently.C. coliharbors a large set of genes associated with lipooligosaccharide biosynthesis, including genes for several putative glycosyltransferases involved in the synthesis of sialylated lipooligosaccharide inCampylobacter jejuni. In the present study,C. coliwas found to express lipooligosaccharide structures containing sialic acid and other nonulosonate acids. These findings have a strong impact on our understanding ofC. coliecology, host-pathogen interaction, and pathogenesis.

scholarly journals Diversification of Campylobacter jejuni Flagellar C-Ring Composition Impacts Its Structure and Function in Motility, Flagellar Assembly, and Cellular Processes

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Louie D. Henderson ◽  
Teige R. S. Matthews-Palmer ◽  
Connor J. Gulbronson ◽  
Deborah A. Ribardo ◽  
Morgan Beeby ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Content Type ◽  
Cellular Processes ◽  
Spatial Regulation ◽  
Flagellar Motors ◽  
Core Components ◽  
Flagellar Assembly ◽  
And Function ◽  
Conserved Core ◽  
Flagellar Biogenesis

ABSTRACT Bacterial flagella are reversible rotary motors that rotate external filaments for bacterial propulsion. Some flagellar motors have diversified by recruiting additional components that influence torque and rotation, but little is known about the possible diversification and evolution of core motor components. The mechanistic core of flagella is the cytoplasmic C ring, which functions as a rotor, directional switch, and assembly platform for the flagellar type III secretion system (fT3SS) ATPase. The C ring is composed of a ring of FliG proteins and a helical ring of surface presentation of antigen (SPOA) domains from the switch proteins FliM and one of two usually mutually exclusive paralogs, FliN or FliY. We investigated the composition, architecture, and function of the C ring of Campylobacter jejuni, which encodes FliG, FliM, and both FliY and FliN by a variety of interrogative approaches. We discovered a diversified C. jejuni C ring containing FliG, FliM, and both FliY, which functions as a classical FliN-like protein for flagellar assembly, and FliN, which has neofunctionalized into a structural role. Specific protein interactions drive the formation of a more complex heterooligomeric C. jejuni C-ring structure. We discovered that this complex C ring has additional cellular functions in polarly localizing FlhG for numerical regulation of flagellar biogenesis and spatial regulation of division. Furthermore, mutation of the C. jejuni C ring revealed a T3SS that was less dependent on its ATPase complex for assembly than were other systems. Our results highlight considerable evolved flagellar diversity that impacts motor output, biogenesis, and cellular processes in different species. IMPORTANCE The conserved core of bacterial flagellar motors reflects a shared evolutionary history that preserves the mechanisms essential for flagellar assembly, rotation, and directional switching. In this work, we describe an expanded and diversified set of core components in the Campylobacter jejuni flagellar C ring, the mechanistic core of the motor. Our work provides insight into how usually conserved core components may have diversified by gene duplication, enabling a division of labor of the ancestral protein between the two new proteins, acquisition of new roles in flagellar assembly and motility, and expansion of the function of the flagellum beyond motility, including spatial regulation of cell division and numerical control of flagellar biogenesis in C. jejuni. Our results highlight that relatively small changes, such as gene duplications, can have substantial ramifications on the cellular roles of a molecular machine.

scholarly journals Regulation of OmpA Translation and Shigella dysenteriae Virulence by an RNA Thermometer

2019 ◽  
Vol 88 (3) ◽  
Author(s):  
Erin R. Murphy ◽  
Johanna Roßmanith ◽  
Jacob Sieg ◽  
Megan E. Fris ◽  
Hebaallaha Hussein ◽  
...  
Keyword(s):  
In Silico ◽  
Bacterial Species ◽  
Regulation Of Gene Expression ◽  
Structure And Function ◽  
Shigella Dysenteriae ◽  
Content Type ◽  
Bacterial Physiology ◽  
Wide Range ◽  
Rna Thermometer ◽  
And Function

ABSTRACT RNA thermometers are cis-acting riboregulators that mediate the posttranscriptional regulation of gene expression in response to environmental temperature. Such regulation is conferred by temperature-responsive structural changes within the RNA thermometer that directly result in differential ribosomal binding to the regulated transcript. The significance of RNA thermometers in controlling bacterial physiology and pathogenesis is becoming increasingly clear. This study combines in silico, molecular genetics, and biochemical analyses to characterize both the structure and function of a newly identified RNA thermometer within the ompA transcript of Shigella dysenteriae. First identified by in silico structural predictions, genetic analyses have demonstrated that the ompA RNA thermometer is a functional riboregulator sufficient to confer posttranscriptional temperature-dependent regulation, with optimal expression observed at the host-associated temperature of 37°C. Structural studies and ribosomal binding analyses have revealed both increased exposure of the ribosomal binding site and increased ribosomal binding to the ompA transcript at permissive temperatures. The introduction of site-specific mutations predicted to alter the temperature responsiveness of the ompA RNA thermometer has predictable consequences for both the structure and function of the regulatory element. Finally, in vitro tissue culture-based analyses implicate the ompA RNA thermometer as a bona fide S. dysenteriae virulence factor in this bacterial pathogen. Given that ompA is highly conserved among Gram-negative pathogens, these studies not only provide insight into the significance of riboregulation in controlling Shigella virulence, but they also have the potential to facilitate further understanding of the physiology and/or pathogenesis of a wide range of bacterial species.

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