1
|
Duong CN, Brückner R, Schmitt M, Nottebaum AF, Braun LJ, Meyer Zu Brickwedde M, Ipe U, Vom Bruch H, Schöler HR, Trapani G, Trappmann B, Ebrahimkutty MP, Huveneers S, de Rooij J, Ishiyama N, Ikura M, Vestweber D. Force-induced changes of α-catenin conformation stabilize vascular junctions independently of vinculin. J Cell Sci 2021; 134:273834. [PMID: 34851405 PMCID: PMC8729784 DOI: 10.1242/jcs.259012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 11/18/2021] [Indexed: 11/20/2022] Open
Abstract
Cadherin-mediated cell adhesion requires anchoring via the β-catenin–α-catenin complex to the actin cytoskeleton, yet, α-catenin only binds F-actin weakly. A covalent fusion of VE-cadherin to α-catenin enhances actin anchorage in endothelial cells and strongly stabilizes endothelial junctions in vivo, blocking inflammatory responses. Here, we have analyzed the underlying mechanism. We found that VE-cadherin–α-catenin constitutively recruits the actin adaptor vinculin. However, removal of the vinculin-binding region of α-catenin did not impair the ability of VE-cadherin–α-catenin to enhance junction integrity. Searching for an alternative explanation for the junction-stabilizing mechanism, we found that an antibody-defined epitope, normally buried in a short α1-helix of the actin-binding domain (ABD) of α-catenin, is openly displayed in junctional VE-cadherin–α-catenin chimera. We found that this epitope became exposed in normal α-catenin upon triggering thrombin-induced tension across the VE-cadherin complex. These results suggest that the VE-cadherin–α-catenin chimera stabilizes endothelial junctions due to conformational changes in the ABD of α-catenin that support constitutive strong binding to actin. Summary: There are novel antibody epitopes at the actin-binding domain of α-catenin that correlate with high affinity binding and are exposed in junction-stabilizing VE-cadherin–α-catenin fusion proteins.
Collapse
Affiliation(s)
- Cao Nguyen Duong
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Randy Brückner
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Martina Schmitt
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Astrid F Nottebaum
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Laura J Braun
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Marika Meyer Zu Brickwedde
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Ute Ipe
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Hermann Vom Bruch
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Hans R Schöler
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Giuseppe Trapani
- Bioactive Materials Laboratory, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Britta Trappmann
- Bioactive Materials Laboratory, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| | - Mirsana P Ebrahimkutty
- Institute of Medical Physics and Biophysics, University of Muenster, Muenster 48149, Germany
| | - Stephan Huveneers
- Amsterdam University Medical Center, Location AMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Johan de Rooij
- Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Noboru Ishiyama
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Dietmar Vestweber
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, D-48149 Münster, Germany
| |
Collapse
|
2
|
Elsheikh AA, Braun LJ, Mansour SMG, Orabi A, Alqahtani AS, Benfield DA, Chase CCL. The effect of human interferon alpha on replication of different bovine viral diarrhea virus strains. Acta Virol 2019; 63:261-269. [PMID: 31507191 DOI: 10.4149/av_2019_303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bovine viral diarrhea virus (BVDV) exists in two main biotypes: cytopathic (cp) and noncytopathic (ncp). Although some studies were done on the effect of interferon alpha (IFN-α) on BVDV, the effect of exogenous IFN against BVDV biotypes remains unclear. In the present study, we evaluated the comparative effect of exogenous human IFN-α (HuIFN-α) on different BVDV biotypes and genotypes. The results showed that exogenous HuIFN-α greatly inhibited the growth of different BVDV biotypes and genotypes. However, HuINF-α has a significant inhibitory effect on cp biotype compared to ncp one without significant variation between different genotypes. The effect of HuIFN-α on BVDV reached the maximum level at early stages of infection (0-20 h post infection) and increased in a dose-dependent manner (10-500 U/ml). Quantitative real-time RT-PCR was used to evaluate the effect of exogenous HuIFN-α on RNA synthesis of both BVDV biotypes. HuIFN-α reduced RNA production of cp by 4 logs compared to only 2 logs for ncp strains. Additionally, the antiviral effect of IFN-α against both BVDV biotypes seems to be independent of the RNA-dependent protein kinase (PKR) activation as assayed by direct analysis of in vivo phosphorylation of eIF2-α and by 2-aminopurine (2-AP) treatment. Collectively, these results indicated that the exogenous HuIFN-α treatment has an inhibitory effect not only on cp BVDV biotype but also on the ncp BVDV. The antiviral effect of exogenous HuIFN-α was biotype, time, dose but not genotype dependent. PKR has no role in the inhibitory effect suggesting that other IFN-antiviral pathways were involved. Keywords: BVDV biotypes; HuIFN-α; RNA synthesis; PKR-independent.
Collapse
|
3
|
Braun LJ, Zinnhardt M, Vockel M, Drexler HC, Peters K, Vestweber D. VE-PTP inhibition stabilizes endothelial junctions by activating FGD5. EMBO Rep 2019; 20:e47046. [PMID: 31267715 PMCID: PMC6607018 DOI: 10.15252/embr.201847046] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 04/01/2019] [Accepted: 04/18/2019] [Indexed: 01/06/2023] Open
Abstract
Inhibition of VE-PTP, an endothelial receptor-type tyrosine phosphatase, triggers phosphorylation of the tyrosine kinase receptor Tie-2, which leads to the suppression of inflammation-induced vascular permeability. Analyzing the underlying mechanism, we show here that inhibition of VE-PTP and activation of Tie-2 induce tyrosine phosphorylation of FGD5, a GTPase exchange factor (GEF) for Cdc42, and stimulate its translocation to cell contacts. Interfering with the expression of FGD5 blocks the junction-stabilizing effect of VE-PTP inhibition in vitro and in vivo. Likewise, FGD5 is required for strengthening cortical actin bundles and inhibiting radial stress fiber formation, which are each stimulated by VE-PTP inhibition. We identify Y820 of FGD5 as the direct substrate for VE-PTP. The phosphorylation of FGD5-Y820 is required for the stabilization of endothelial junctions and for the activation of Cdc42 by VE-PTP inhibition but is dispensable for the recruitment of FGD5 to endothelial cell contacts. Thus, activation of FGD5 is a two-step process that comprises membrane recruitment and phosphorylation of Y820. These steps are necessary for the junction-stabilizing effect stimulated by VE-PTP inhibition and Tie-2 activation.
Collapse
Affiliation(s)
- Laura J Braun
- Max Planck Institute of Molecular BiomedicineMünsterGermany
| | | | - Matthias Vockel
- Max Planck Institute of Molecular BiomedicineMünsterGermany
- Present address:
Institute for Human GeneticsUniversity of MünsterMünsterGermany
| | | | | | | |
Collapse
|
4
|
Xu L, Braun LJ, Rönnlund D, Widengren J, Aspenström P, Gad AKB. Nanoscale localization of proteins within focal adhesions indicates discrete functional assemblies with selective force-dependence. FEBS J 2018. [PMID: 29542240 DOI: 10.1111/febs.14433] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Focal adhesions (FAs) are subcellular regions at the micrometer scale that link the cell to the surrounding microenvironment and control vital cell functions. However, the spatial architecture of FAs remains unclear at the nanometer scale. We used two-color and three-color super-resolution stimulated emission depletion microscopy to determine the spatial distributions and co-localization of endogenous FA components in fibroblasts. Our data indicate that adhesion proteins inside, but not outside, FAs are organized into nanometer size units of multi-protein assemblies. The loss of contractile force reduced the nanoscale co-localization between different types of proteins, while it increased this co-localization between markers of the same type. This suggests that actomyosin-dependent force exerts a nonrandom, specific, control of the localization of adhesion proteins within cell-matrix adhesions. These observations are consistent with the possibility that proteins in cell-matrix adhesions are assembled in nanoscale particles, and that force regulates the localization of the proteins therein in a protein-specific manner. This detailed knowledge of how the organization of FA components at the nanometer scale is linked to the capacity of the cells to generate contractile forces expands our understanding of cell adhesion in health and disease.
Collapse
Affiliation(s)
- Lei Xu
- Experimental Biomolecular Physics, Department of Applied Physics, KTH Royal Institute of Technology, AlbaNova University Center, Stockholm, Sweden
| | - Laura J Braun
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Daniel Rönnlund
- Experimental Biomolecular Physics, Department of Applied Physics, KTH Royal Institute of Technology, AlbaNova University Center, Stockholm, Sweden
| | - Jerker Widengren
- Experimental Biomolecular Physics, Department of Applied Physics, KTH Royal Institute of Technology, AlbaNova University Center, Stockholm, Sweden
| | - Pontus Aspenström
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Annica K B Gad
- CQM - Centro de Químíca da Madeira, Universidade da Madeira, Funchal, Portugal
| |
Collapse
|
5
|
Xu L, Rönnlund D, Aspenström P, Braun LJ, Gad AKB, Widengren J. Resolution, target density and labeling effects in colocalization studies - suppression of false positives by nanoscopy and modified algorithms. FEBS J 2016; 283:882-98. [PMID: 26756570 DOI: 10.1111/febs.13652] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 11/10/2015] [Accepted: 01/08/2016] [Indexed: 11/28/2022]
Abstract
Colocalization analyses of fluorescence images are extensively used to quantify molecular interactions in cells. In recent years, fluorescence nanoscopy has approached resolutions close to molecular dimensions. However, the extent to which image resolution influences different colocalization estimates has not been systematically investigated. In this work, we applied simulations and resolution-tunable stimulated emission depletion microscopy to evaluate how the resolution, molecular density and label size of targeted molecules influence estimates of the most commonly used colocalization algorithms (Pearson correlation coefficient, Manders' M1 and M2 coefficients), as well as estimates by the image cross-correlation spectroscopy method. We investigated the practically measureable extents of colocalization for stimulated emission depletion microscopy with positive and negative control samples with an aim to identifying the strengths and weaknesses of nanoscopic techniques for colocalization studies. At a typical optical resolution of a confocal microscope (200-300 nm), our results indicate that the extent of colocalization is typically overestimated by the tested algorithms, especially at high molecular densities. Only minor effects of this kind were observed at higher resolutions (< 60 nm). By contrast, underestimation of colocalization may occur if the resolution is close to the size of the label/affinity molecules themselves. To suppress false positives at confocal resolutions and high molecular densities, we introduce a statistical variant of Costes' threshold searching algorithm, used in combination with correlation-based methods like the Pearson coefficient and the image cross-correlation spectroscopy approach, to set intensity thresholds separating background noise from signals.
Collapse
Affiliation(s)
- Lei Xu
- Department of Applied Physics, Royal Institute of Technology, KTH, Stockholm, Sweden
| | - Daniel Rönnlund
- Department of Applied Physics, Royal Institute of Technology, KTH, Stockholm, Sweden
| | - Pontus Aspenström
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
| | - Laura J Braun
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
| | - Annica K B Gad
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Jerker Widengren
- Department of Applied Physics, Royal Institute of Technology, KTH, Stockholm, Sweden
| |
Collapse
|
6
|
Ridpath JF, Bayles DO, Neill JD, Falkenberg SM, Bauermann FV, Holler L, Braun LJ, Young DB, Kane SE, Chase CCL. Comparison of the breadth and complexity of bovine viral diarrhea (BVDV) populations circulating in 34 persistently infected cattle generated in one outbreak. Virology 2015; 485:297-304. [PMID: 26319211 DOI: 10.1016/j.virol.2015.07.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 07/28/2015] [Accepted: 07/30/2015] [Indexed: 11/18/2022]
Abstract
Exposure to bovine viral diarrhea viruses (BVDV) results in acute and persistent infections. Persistent infections result from in utero exposure during the first trimester of gestation. Clinical presentation, in persistently infected cattle (PI), is highly variable. The reasons for this variation is largely unknown. The BVDV circulating in PI exist as quasispecies (swarms of individual viruses). An outbreak resulting in 34 PI cattle presented an opportunity to compare a large number of PI׳s. Methods were developed to compare the circulating viral populations within PI animals. It was found that PI animals generated in the same outbreak carry circulating viral populations that differ widely in size and diversity. Further, it was demonstrated that variation in PI viral populations could be used as a quantifiable phenotype. This observation makes it possible to test the correlation of this phenotype to other phenotypes such as growth rate, congenital defects, viral shed and cytokine expression.
Collapse
Affiliation(s)
- J F Ridpath
- National Animal Disease Center, ARS/USDA, Ames, IA 50010, United States.
| | - D O Bayles
- National Animal Disease Center, ARS/USDA, Ames, IA 50010, United States
| | - J D Neill
- National Animal Disease Center, ARS/USDA, Ames, IA 50010, United States
| | - S M Falkenberg
- National Animal Disease Center, ARS/USDA, Ames, IA 50010, United States
| | - F V Bauermann
- National Animal Disease Center, ARS/USDA, Ames, IA 50010, United States
| | - L Holler
- Department of Veterinary and Biomedical Sciences, South Dakota State University Brookings, SD 57006, United States
| | - L J Braun
- Department of Veterinary and Biomedical Sciences, South Dakota State University Brookings, SD 57006, United States
| | - D B Young
- Antelope Research Station, Buffalo, SD 57720, United States
| | - S E Kane
- Department of Veterinary and Biomedical Sciences, South Dakota State University Brookings, SD 57006, United States
| | - C C L Chase
- Department of Veterinary and Biomedical Sciences, South Dakota State University Brookings, SD 57006, United States
| |
Collapse
|
7
|
Abstract
Peripheral blood mononuclear cells (PBMCs) from 5 calves (3 controls and 2 vaccinates) used in a bovine herpesvirus 1 (BHV-1) vaccine study with a BHV-1 Cooper strain challenge were collected 6 months after challenge. The PBMCs from the control animals were positive by immunofluorescence for the BHV-1 glycoprotein D (gD) while the vaccinates were negative. The PBMC samples from 4 of the 5 animals were examined for BHV-1 DNA by polymerase chain reaction (PCR) and for gD immunofluorescence at 8 months after challenge. The BHV-1 DNA and viral antigen were detected in PBMC samples at 8 months postinfection, but no virus was isolated.
Collapse
Affiliation(s)
- P Wang
- Department of Veterinary Science, South Dakota State University, Brookings 57007, USA
| | | | | | | |
Collapse
|