scholarly journals The Chlamydia type III effector TarP alters the dynamics and organization of host cell focal adhesions

2018 ◽  
Author(s):  
António T. Pedrosa ◽  
Korinn N. Murphy ◽  
Ana T. Nogueira ◽  
Amanda J. Brinkworth ◽  
Tristan R. Thwaites ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Focal Adhesions ◽  
Super Resolution ◽  
Vertical Displacement ◽  
Cell Types ◽  
Host Protein ◽  
Specific Domain ◽  
Type Iii Effector ◽  
Type Iii ◽  
C Terminus

AbstractThe human pathogen Chlamydia trachomatis targets epithelial cells lining the genital mucosa. We observed that infection of various cell types, including fibroblasts and epithelial cells resulted in the formation of unusually stable focal adhesions that resisted disassembly induced by the myosin II inhibitor, blebbistatin. Super-resolution microscopy revealed in infected cells the vertical displacement of paxillin and FAK from the signaling layer of focal adhesions; while vinculin remained in its normal position within the force transduction layer. The candidate type III effector TarP which localized to focal adhesions during infection and when expressed ectopically, was sufficient to mimic both the reorganization and blebbistatin-resistant phenotypes. These effects of TarP, including its localization to focal adhesions required interaction with the host protein vinculin through a specific domain at the C-terminus of TarP. The consequence of Chlamydia-stabilized focal adhesions was restricted cell motility and enhanced attachment to the extracellular matrix. Thus, via a novel mechanism, Chlamydia inserts TarP within focal adhesions to alter their organization and dynamics.

scholarly journals A post-invasion role for Chlamydia type III effector TarP in modulating the dynamics and organization of host cell focal adhesions

2020 ◽  
Vol 295 (43) ◽  
pp. 14763-14779
Author(s):  
António T. Pedrosa ◽  
Korinn N. Murphy ◽  
Ana T. Nogueira ◽  
Amanda J. Brinkworth ◽  
Tristan R. Thwaites ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Focal Adhesions ◽  
Vertical Displacement ◽  
Cell Types ◽  
Host Protein ◽  
Specific Domain ◽  
Type Iii Effector ◽  
Superresolution Microscopy ◽  
Type Iii ◽  
C Terminus

The human pathogen Chlamydia trachomatis targets epithelial cells lining the genital mucosa. We observed that infection of various cell types, including fibroblasts and epithelial cells resulted in the formation of unusually stable and mature focal adhesions that resisted disassembly induced by the myosin II inhibitor, blebbistatin. Superresolution microscopy revealed in infected cells the vertical displacement of paxillin and focal adhesion kinase from the signaling layer of focal adhesions, whereas vinculin remained in its normal position within the force transduction layer. The candidate type III effector TarP, which localized to focal adhesions during infection and when expressed ectopically, was sufficient to mimic both the reorganization and blebbistatin-resistant phenotypes. These effects of TarP, including its localization to focal adhesions, required a post-invasion interaction with the host protein vinculin through a specific domain at the C terminus of TarP. This interaction is repurposed from an actin-recruiting and -remodeling complex to one that mediates nanoarchitectural and dynamic changes of focal adhesions. The consequence of Chlamydia-stabilized focal adhesions was restricted cell motility and enhanced attachment to the extracellular matrix. Thus, via a novel mechanism, Chlamydia inserts TarP within focal adhesions to alter their organization and stability.

scholarly journals The nanoscale organization of the Wnt signaling integrator Dishevelled in the development-essential vegetal cortex domain of an egg and early embryo

2021 ◽  
Author(s):  
John H. Henson ◽  
Bakary Samasa ◽  
Charles B. Shuster ◽  
Athula H. Wikramanayake
Keyword(s):  
Plasma Membrane ◽  
Sea Urchin ◽  
Super Resolution ◽  
Cell Types ◽  
Early Embryo ◽  
Ultrastructural Organization ◽  
C Terminus ◽  
Pathway Activation ◽  
Vegetal Cortex ◽  
Canonical Wnt

AbstractWnt/β-catenin (cWnt) signaling is a crucial regulator of development and Dishevelled (Dsh/Dvl) functions as an integral part of this pathway by linking Wnt binding to the frizzled:LRP5/6 receptor complex with β-catenin-stimulated gene expression. In many cell types Dsh has been localized to ill-defined cytoplasmic puncta, however in sea urchin eggs and embryos confocal fluorescence microscopy has shown that Dsh is localized to puncta present in a novel and development-essential vegetal cortex domain (VCD). In the present study, we used super-resolution light microscopy and platinum replica TEM to provide the first views of the ultrastructural organization of Dsh within the sea urchin VCD. 3D-SIM imaging of isolated egg cortices demonstrated the concentration gradient-like distribution of Dsh in the VCD, whereas higher resolution STED imaging revealed that some individual Dsh puncta consisted of more than one fluorescent source. Platinum replica immuno-TEM localization showed that Dsh puncta on the cytoplasmic face of the plasma membrane consisted of aggregates of pedestal-like structures each individually labeled with the C-terminus specific Dsh antibody. These aggregates were resistant to detergent extraction and treatment with drugs that disrupt actin filaments or inhibit myosin II contraction, and coexisted with the first division actomyosin contractile ring. These results confirm and extend previous studies and reveal, for the first time in any cell type, the nanoscale organization of plasma membrane tethered Dsh. Our current working hypothesis is that these Dsh pedestals represent a prepositioned scaffold organization that is important for canonical Wnt pathway activation at the sea urchin vegetal organization and may also be relevant to the submembranous Dsh puncta present in other eggs and embryos.

scholarly journals Salmonella Type III Effector AvrA Stabilizes Cell Tight Junctions to Inhibit Inflammation in Intestinal Epithelial Cells

PLoS ONE ◽  
2008 ◽  
Vol 3 (6) ◽  
pp. e2369 ◽  
Author(s):  
Anne P. Liao ◽  
Elaine O. Petrof ◽  
Sumalatha Kuppireddi ◽  
Yun Zhao ◽  
Yinglin Xia ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Tight Junctions ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Type Iii Effector ◽  
Type Iii

scholarly journals Pseudomonas syringae type III effector HopAF1 suppresses plant immunity by targeting methionine recycling to block ethylene induction

2016 ◽  
Vol 113 (25) ◽  
pp. E3577-E3586 ◽  
Author(s):  
Erica J. Washington ◽  
M. Shahid Mukhtar ◽  
Omri M. Finkel ◽  
Li Wan ◽  
Mark J. Banfield ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Pathogens ◽  
Plant Immunity ◽  
Ethylene Biosynthesis ◽  
Host Protein ◽  
Loss Of Function ◽  
Type Iii Effector ◽  
Type Iii ◽  
Host Defense Response ◽  
Molecular Patterns

HopAF1 is a type III effector protein of unknown function encoded in the genomes of several strains of Pseudomonas syringae and other plant pathogens. Structural modeling predicted that HopAF1 is closely related to deamidase proteins. Deamidation is the irreversible substitution of an amide group with a carboxylate group. Several bacterial virulence factors are deamidases that manipulate the activity of specific host protein substrates. We identified Arabidopsis methylthioadenosine nucleosidase proteins MTN1 and MTN2 as putative targets of HopAF1 deamidation. MTNs are enzymes in the Yang cycle, which is essential for the high levels of ethylene biosynthesis in Arabidopsis. We hypothesized that HopAF1 inhibits the host defense response by manipulating MTN activity and consequently ethylene levels. We determined that bacterially delivered HopAF1 inhibits ethylene biosynthesis induced by pathogen-associated molecular patterns and that Arabidopsis mtn1 mtn2 mutant plants phenocopy the effect of HopAF1. Furthermore, we identified two conserved asparagines in MTN1 and MTN2 from Arabidopsis that confer loss of function phenotypes when deamidated via site-specific mutation. These residues are potential targets of HopAF1 deamidation. HopAF1-mediated manipulation of Yang cycle MTN proteins is likely an evolutionarily conserved mechanism whereby HopAF1 orthologs from multiple plant pathogens contribute to disease in a large variety of plant hosts.

scholarly journals Shigellaenterotoxin-2 is a type III effector that participates inShigella-induced interleukin 8 secretion by epithelial cells

2011 ◽  
Vol 61 (3) ◽  
pp. 332-339 ◽  
Author(s):  
Mauricio J. Farfán ◽  
Cecilia S. Toro ◽  
Eileen M. Barry ◽  
James P. Nataro
Keyword(s):  
Epithelial Cells ◽  
Interleukin 8 ◽  
Type Iii Effector ◽  
Type Iii

scholarly journals Loss of the Human Cytomegalovirus US16 Protein Abrogates Virus Entry into Endothelial and Epithelial Cells by Reducing the Virion Content of the Pentamer

2017 ◽  
Vol 91 (11) ◽  
Author(s):  
Anna Luganini ◽  
Noemi Cavaletto ◽  
Stefania Raimondo ◽  
Stefano Geuna ◽  
Giorgio Gribaudo
Keyword(s):  
Epithelial Cells ◽  
Human Cytomegalovirus ◽  
Virus Entry ◽  
Regulatory Protein ◽  
Direct Consequence ◽  
Cell Types ◽  
Target Cells ◽  
C Terminus ◽  
Viral Particles ◽  
Low Passage

ABSTRACT The human cytomegalovirus (HCMV) US12 gene family encodes a group of predicted seven-transmembrane proteins whose functions have yet to be established. While inactivation of individual US12 members in laboratory strains of HCMV does not affect viral replication in fibroblasts, disruption of the US16 gene in the low-passage-number TR strain prevents viral growth in endothelial and epithelial cells. In these cells, the US16-null viruses fail to express immediate early (IE), early (E), and late (L) viral proteins due to a defect which occurs prior to IE gene expression. Here, we show that this defective phenotype is a direct consequence of deficiencies in the entry of US16-null viruses in these cell types due to an impact on the gH/gL/UL128/UL130/UL131A (pentamer) complex. Indeed, viral particles released from fibroblasts infected with US16-null viruses were defective for the pentamer, thus preventing entry during infections of endothelial and epithelial cells. A link between pUS16 and the pentamer was further supported by the colocalization of pUS16 and pentamer proteins within the cytoplasmic viral assembly compartment (cVAC) of infected fibroblasts. Deletion of the C-terminal tail of pUS16 reproduced the defective growth phenotype and alteration of virion composition as US16-null viruses. However, the pentamer assembly and trafficking to the cVAC were not affected by the lack of the C terminus of pUS16. Coimmunoprecipitation results then indicated that US16 interacts with pUL130 but not with the mature pentamer or gH/gL/gO. Together, these results suggest that pUS16 contributes to the tropism of HCMV by influencing the content of the pentamer into virions. IMPORTANCE Human cytomegalovirus (HCMV) is major pathogen in newborns and immunocompromised individuals. A hallmark of HCMV pathogenesis is its ability to productively replicate in an exceptionally broad range of target cells. The virus infects a variety of cell types by exploiting different forms of the envelope glycoprotein gH/gL hetero-oligomers, which allow entry into many cell types through different pathways. For example, incorporation of the pentameric gH/gL/UL128/UL130/UL131A complex into virions is a prerequisite for infection of endothelial and epithelial cells. Here, we show that the absence of US16, a thus far uncharacterized HCMV multitransmembrane protein, abrogates virus entry into endothelial and epithelial cells and that this defect is due to the lack of adequate amounts of the pentameric complex in extracellular viral particles. Our study suggests pUS16 as a novel viral regulatory protein important for shaping virion composition in a manner that influences HCMV cell tropism.

scholarly journals Cell-Type-Specific Transcription of Innate Immune Regulators in response to HMPV Infection

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Simon Loevenich ◽  
Jostein Malmo ◽  
Ann Magritt Liberg ◽  
Tatyana Sherstova ◽  
Youxian Li ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Immune Responses ◽  
Mrna Expression ◽  
Cell Types ◽  
Innate Immune ◽  
Cell Type ◽  
Type Iii ◽  
Immune Mediators ◽  
Hmpv Infection ◽  
Type Iii Ifn

Human metapneumovirus (HMPV) may cause severe respiratory disease. The early innate immune response to viruses like HMPV is characterized by induction of antiviral interferons (IFNs) and proinflammatory immune mediators that are essential in shaping adaptive immune responses. Although innate immune responses to HMPV have been comprehensively studied in mice and murine immune cells, there is less information on these responses in human cells, comparing different cell types infected with the same HMPV strain. The aim of this study was to characterize the HMPV-induced mRNA expression of critical innate immune mediators in human primary cells relevant for airway disease. In particular, we determined type I versus type III IFN expression in human epithelial cells and monocyte-derived macrophages (MDMs) and dendritic cells (MDDCs). In epithelial cells, HMPV induced only low levels of IFN-β mRNA, while a robust mRNA expression of IFN-λs was found in epithelial cells, MDMs, and MDDCs. In addition, we determined induction of the interferon regulatory factors (IRFs) IRF1, IRF3, and IRF7 and critical inflammatory cytokines (IL-6, IP-10, and IL-1β). Interestingly, IRF1 mRNA was predominantly induced in MDMs and MDDCs. Overall, our results suggest that for HMPV infection of MDDCs, MDMs, NECs, and A549 cells (the cell types examined), cell type is a strong determinator of the ability of HMPV to induce different innate immune mediators. HMPV induces the transcription of IFN-β and IRF1 to higher extents in MDMs and MDDCs than in A549s and NECs, whereas the induction of type III IFN-λ and IRF7 is considerable in MDMs, MDDCs, and A549 epithelial cells.

scholarly journals Influence of polydimethylsiloxane substrate stiffness on corneal epithelial cells

2019 ◽  
Vol 6 (12) ◽  
pp. 191796 ◽  
Author(s):  
Sophia Masterton ◽  
Mark Ahearne
Keyword(s):  
Epithelial Cells ◽  
Focal Adhesions ◽  
Cell Types ◽  
Corneal Epithelial Cell ◽  
Cell Phenotype ◽  
Epithelial Cell Line ◽  
Corneal Epithelial Cells ◽  
Corneal Epithelial ◽  
Material Stiffness ◽  
Epithelial Marker

Many cell types are known to modulate their behaviour in response to changes in material stiffness; however, little is known about how stiffness affects corneal epithelial cells. This study aims to investigate the response of a corneal epithelial cell line to polydimethylsiloxane (PDMS) substrates with a range of Young's moduli from 10 to 1500 kPa. Cellular morphology, proliferation, differentiation and mechanobiology were examined. Cells grown on PDMS adopted the typical cobblestone morphology exhibited by the corneal epithelium. Proliferative markers pERK and Ki67 were higher in cells cultured on stiffer substrates compared with those on softer substrates. Material stiffness was also found to influence the cell phenotype with cells on stiffer substrates having higher cytokeratin 3 gene expression, a mature epithelial marker, while cells on softer substrates expressed more cytokeratin 14, a basal epithelial marker. Cells grown on softer substrates also displayed higher levels of focal adhesions and intermediate filaments compared with cells on stiff substrates. This research will aid in designing novel biomaterials for the culture and transplantation of corneal epithelial cells.

scholarly journals The Shigella type III effector IpgD recodes Ca 2+ signals during invasion of epithelial cells

2017 ◽  
Vol 36 (17) ◽  
pp. 2567-2580 ◽  
Author(s):  
Chun Hui Sun ◽  
Benjamin Wacquier ◽  
Daniel I Aguilar ◽  
Nathalie Carayol ◽  
Kevin Denis ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Type Iii Effector ◽  
Type Iii
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