scholarly journals Reevaluating αE-catenin monomer and homodimer functions by characterizing E-cadherin/αE-catenin chimeras

2015 ◽  
Vol 210 (7) ◽  
pp. 1065-1074 ◽  
Author(s):  
Julie M. Bianchini ◽  
Khameeka N. Kitt ◽  
Martijn Gloerich ◽  
Sabine Pokutta ◽  
William I. Weis ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Intercellular Adhesion ◽  
Dependent Cell ◽  
In Cells ◽  
E Cadherin ◽  
Cell Cell

As part of the E-cadherin–β-catenin–αE-catenin complex (CCC), mammalian αE-catenin binds F-actin weakly in the absence of force, whereas cytosolic αE-catenin forms a homodimer that interacts more strongly with F-actin. It has been concluded that cytosolic αE-catenin homodimer is not important for intercellular adhesion because E-cadherin/αE-catenin chimeras thought to mimic the CCC are sufficient to induce cell–cell adhesion. We show that, unlike αE-catenin in the CCC, these chimeras homodimerize, bind F-actin strongly, and inhibit the Arp2/3 complex, all of which are properties of the αE-catenin homodimer. To more accurately mimic the junctional CCC, we designed a constitutively monomeric chimera, and show that E-cadherin–dependent cell adhesion is weaker in cells expressing this chimera compared with cells in which αE-catenin homodimers are present. Our results demonstrate that E-cadherin/αE-catenin chimeras used previously do not mimic αE-catenin in the native CCC, and imply that both CCC-bound monomer and cytosolic homodimer αE-catenin are required for strong cell–cell adhesion.

scholarly journals Structure-Based Virtual Screening Allows the Identification of Efficient Modulators of E-Cadherin-Mediated Cell–Cell Adhesion

2019 ◽  
Vol 20 (14) ◽  
pp. 3404 ◽  
Author(s):  
Andrea Dalle Vedove ◽  
Federico Falchi ◽  
Stefano Donini ◽  
Aurelie Dobric ◽  
Sebastien Germain ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Virtual Screening ◽  
Adherens Junction ◽  
Large Family ◽  
Calcium Dependent ◽  
Molecule Inhibitor ◽  
Dependent Cell ◽  
Cell Adhesion Proteins ◽  
E Cadherin ◽  
Cell Cell

Cadherins are a large family of transmembrane calcium-dependent cell adhesion proteins that orchestrate adherens junction formation and are crucially involved in tissue morphogenesis. Due to their important role in cancer development and metastasis, cadherins can be considered attractive targets for drug discovery. A recent crystal structure of the complex of a cadherin extracellular portion and a small molecule inhibitor allowed the identification of a druggable interface, thus providing a viable strategy for the design of cadherin dimerization modulators. Here, we report on a structure-based virtual screening approach that led to the identification of efficient and selective modulators of E-cadherin-mediated cell–cell adhesion. Of all the putative inhibitors that were identified and experimentally tested by cell adhesion assays using human pancreatic tumor BxPC-3 cells expressing both E-cadherin and P-cadherin, two compounds turned out to be effective in inhibiting stable cell–cell adhesion at micromolar concentrations. Moreover, at the same concentrations, one of them also showed anti-invasive properties in cell invasion assays. These results will allow further development of novel and selective cadherin-mediated cell–cell adhesion modulators for the treatment of a variety of cadherin-expressing solid tumors and for improving the efficiency of drug delivery across biological barriers.

scholarly journals Cadherins Mediate Both the Association between PS1 and β-Catenin and the Effects of PS1 on β-Catenin Stability

2005 ◽  
Vol 280 (43) ◽  
pp. 36007-36012 ◽  
Author(s):  
Geo Serban ◽  
Zen Kouchi ◽  
Lia Baki ◽  
Anastasios Georgakopoulos ◽  
Claudia M. Litterst ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Alzheimer Disease ◽  
Wnt Signaling ◽  
Complex Component ◽  
Cellular Development ◽  
In Cells ◽  
E Cadherin ◽  
Cell Cell

Presenilin1 (PS1), a protein involved in cellular development, forms functional complexes with β-catenin, a regulator of Wnt signaling and cell-cell adhesion. In addition, both proteins have been shown to play important roles in disease including cancer and Alzheimer disease. Although PS1 and β-catenin are found in the same complexes, it is not clear whether they bind directly to each other or a third complex component, like cadherin, may mediate their interactions. Here we show that PS1 and β-catenin form no detectable complexes in cells that express no cadherin. In contrast, these complexes are readily found in E-cadherin containing cells. Furthermore, binding of both PS1 and β-catenin to E-cadherin is necessary for the formation of PS1/β-catenin complexes. Importantly, our data show that binding of PS1 to cadherin mediates the effects of PS1 on the phosphorylation, ubiquitination, and destabilization of β-catenin. Thus, cadherins mediate both the association of PS1 and β-catenin and the effects of PS1 on the cellular levels of β-catenin.

scholarly journals Plakoglobin, or an 83-kD homologue distinct from beta-catenin, interacts with E-cadherin and N-cadherin.

1992 ◽  
Vol 118 (3) ◽  
pp. 671-679 ◽  
Author(s):  
K A Knudsen ◽  
M J Wheelock
Keyword(s):  
Cell Adhesion ◽  
Cell Surface ◽  
Molecular Mass ◽  
Beta Catenin ◽  
Calcium Dependent ◽  
Intracellular Proteins ◽  
Dependent Cell ◽  
Cell Surface Glycoproteins ◽  
E Cadherin ◽  
Cell Cell

E- and N-cadherin are members of a family of calcium-dependent, cell surface glycoproteins involved in cell-cell adhesion. Extracellularly, the transmembrane cadherins self-associate, while, intracellularly, they interact with the actin-based cytoskeleton. Several intracellular proteins, collectively termed catenins, have been noted to co-immunoprecipitate with E- and N-cadherin and are thought to be involved in linking the cadherins to the cytoskeleton. Two catenins have been identified recently: a 102-kD vinculin-like protein (alpha-catenin) and a 92-kD Drosophila armadillo/plakoglobin-like protein (beta-catenin). Here, we show that plakoglobin, or an 83-kD plakoglobin-like protein, co-immunoprecipitates and colocalizes with both E- and N-cadherin. The 83-kD protein is immunologically distinct from the 92-kD beta-catenin and, because of its molecular mass, likely represents the cadherin-associated protein called gamma-catenin. Thus, two different members of a plakoglobin family associate with N- and E-cadherin and, together with the 102-kD alpha-catenin, appear to participate in linking the cadherins to the actin-based cytoskeleton.

Differential regulation of C-CAM isoforms in epithelial cells

1994 ◽  
Vol 107 (5) ◽  
pp. 1205-1216 ◽  
Author(s):  
I. Hunter ◽  
M. Lindh ◽  
B. Obrink
Keyword(s):  
Cell Adhesion ◽  
Cell Surface ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Apical Cell ◽  
Intercellular Adhesion ◽  
Isolated Rat Hepatocytes ◽  
Cell Surface Glycoprotein ◽  
In Cells ◽  
Cell Cell

C-CAM is a Ca(2+)-independent cell adhesion molecule (CAM) that mediates intercellular adhesion of isolated rat hepatocytes. It is widely distributed in epithelia, where its presence both at lateral cell borders and on apical cell surfaces suggests that it may have diverse biological functions. Two major isoforms, C-CAM1 and C-CAM2, which differ in the lengths of their cytoplasmic domains, have been identified. The lack of suitable in vitro systems has so far prevented a detailed study of the physiological role of C-CAM in epithelia. We now report on the identification, biochemical characterization and functional analysis of C-CAM isoforms in the established epithelial cell line NBT II, derived from a chemically induced carcinoma of rat bladder. C-CAM in NBT II cells is a 110–115 kDa cell surface glycoprotein located predominantly at sites of cell-cell contact but also present on the apical cell surface. Northern blotting analysis revealed the presence of both C-CAM1 and C-CAM2, with the major transcripts for both isoforms present within the 4.0 kb size range. The dissociation of NBT II cell colonies by anti-C-CAM antibodies indicated that at least one function of C-CAM in these cells is to mediate intercellular adhesion. The maintenance of extensive cell-cell contacts and the expression of C-CAM at the contact sites in cells grown in low Ca2+ medium suggested that, like its counterpart in hepatocytes, C-CAM in NBT II cells may be a Ca(2+)-independent cell-cell adhesion molecule. The co-localization and coordinate reorganization of both C-CAM and actin by anti-C-CAM antibodies indicated that these two proteins were associated and suggested that interactions with the cytoskeleton may be important for the regulation of C-CAM function. The specific upregulation of C-CAM1 in cells induced to undergo epithelial to mesenchymal-like transitions (EMT) by the serum substitute Ultroser G suggested that C-CAM isoforms are important modulators of the adhesive properties of these cells.

scholarly journals Protein Kinase C Activation Upregulates Intercellular Adhesion of α-Catenin–negative Human Colon Cancer Cell Variants via Induction of Desmosomes

1997 ◽  
Vol 137 (5) ◽  
pp. 1103-1116 ◽  
Author(s):  
Jolanda van Hengel ◽  
Lionel Gohon ◽  
Erik Bruyneel ◽  
Stefan Vermeulen ◽  
Maria Cornelissen ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Cell Adhesion ◽  
Protein Kinase ◽  
Human Colon ◽  
Intercellular Adhesion ◽  
Human Colon Cancer ◽  
Human Colon Carcinoma Cell ◽  
Kinase C ◽  
E Cadherin ◽  
Cell Cell

The α-catenin molecule links E-cadherin/ β-catenin or E-cadherin/plakoglobin complexes to the actin cytoskeleton. We studied several invasive human colon carcinoma cell lines lacking α-catenin. They showed a solitary and rounded morphotype that correlated with increased invasiveness. These round cell variants acquired a more normal epithelial phenotype upon transfection with an α-catenin expression plasmid, but also upon treatment with the protein kinase C (PKC) activator 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Video registrations showed that the cells started to establish elaborated intercellular junctions within 30 min after addition of TPA. Interestingly, this normalizing TPA effect was not associated with α-catenin induction. Classical and confocal immunofluorescence showed only minor TPA-induced changes in E-cadherin staining. In contrast, desmosomal and tight junctional proteins were dramatically rearranged, with a conversion from cytoplasmic clusters to obvious concentration at cell–cell contacts and exposition at the exterior cell surface. Electron microscopical observations revealed the TPA-induced appearance of typical desmosomal plaques. TPA-restored cell–cell adhesion was E-cadherin dependent as demonstrated by a blocking antibody in a cell aggregation assay. Addition of an antibody against the extracellular part of desmoglein-2 blocked the TPA effect, too. Remarkably, the combination of anti–E-cadherin and anti-desmoglein antibodies synergistically inhibited the TPA effect. Our studies show that it is possible to bypass the need for normal α-catenin expression to establish tight intercellular adhesion by epithelial cells. Apparently, the underlying mechanism comprises upregulation of desmosomes and tight junctions by activation of the PKC signaling pathway, whereas E-cadherin remains essential for basic cell–cell adhesion, even in the absence of α-catenin.

scholarly journals Loss of E-cadherin-dependent cell-cell adhesion due to mutation of the beta-catenin gene in a human cancer cell line, HSC-39.

1995 ◽  
Vol 15 (3) ◽  
pp. 1175-1181 ◽  
Author(s):  
J Kawanishi ◽  
J Kato ◽  
K Sasaki ◽  
S Fujii ◽  
N Watanabe ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Cell Line ◽  
Cancer Cell ◽  
Cancer Cell Line ◽  
Cell Aggregation ◽  
Expression Vectors ◽  
Beta Catenin ◽  
Dependent Cell ◽  
E Cadherin ◽  
Cell Cell

Detachment of cell-cell adhesion is indispensable for the first step of invasion and metastasis of cancer. This mechanism is frequently associated with the impairment of either E-cadherin expression or function. However, mechanisms of such abnormalities have not been fully elucidated. In this study, we demonstrated that the function of E-cadherin was completely abolished in the human gastric cancer cell line HSC-39, despite the high expression of E-cadherin, because of mutations in one of the E-cadherin-associated cytoplasmic proteins, beta-catenin. Although immunofluorescence staining of HSC-39 cells by using an anti-E-cadherin antibody (HECD-1) revealed the strong and uniform expression of E-cadherin on the cell surface, cell compaction and cell aggregation were not observed in this cell. Western blotting (immunoblotting) using HECD-1 exhibited a 120-kDa band which is equivalent to normal E-cadherin. Northern (RNA) blotting demonstrated a 4.7-kb band, the same as mature E-cadherin mRNA. Immunoprecipitation of metabolically labeled proteins with HECD-1 revealed three bands corresponding to E-cadherin, alpha-catenin, and gamma-catenin and a 79-kDa band which was apparently smaller than that of normal beta-catenin, indicating truncated beta-catenin. The 79-kDa band was immunologically identified as beta-catenin by using immunoblotting with anti-beta-catenin antibodies. Examination of beta-catenin mRNA by the reverse transcriptase-PCR method revealed a transcript which was shorter than that of normal beta-catenin. The sequencing of PCR product for beta-catenin confirmed deletion in 321 bases from nucleotides +82 to +402. Southern blotting of beta-catenin DNA disclosed mutation at the genomic level. Expression vectors of Beta-catenin were introduced into HSC-39 cells by transfection. In the obtained transfectants, E-cadherin-dependent cell-cell adhesiveness was recovered, as revealed by cell compaction, cell aggregation, and immunoflourescence staining. From these results, it was concluded that in HSC-39 cells, impaired cell-cell adhesion is due to mutations in beta-catenin which results in the dysfunction of E-cadherin.

scholarly journals Interaction of alpha-actinin with the cadherin/catenin cell-cell adhesion complex via alpha-catenin.

1995 ◽  
Vol 130 (1) ◽  
pp. 67-77 ◽  
Author(s):  
K A Knudsen ◽  
A P Soler ◽  
K R Johnson ◽  
M J Wheelock
Keyword(s):  
Cell Adhesion ◽  
Cytoskeletal Proteins ◽  
Beta Catenin ◽  
Independent Manner ◽  
Intracellular Proteins ◽  
Direct Association ◽  
Dependent Cell ◽  
Adhesion Complex ◽  
E Cadherin ◽  
Cell Cell

Cadherins are Ca(2+)-dependent, cell surface glycoproteins involved in cell-cell adhesion. Extracellularly, transmembrane cadherins such as E-, P-, and N-cadherin self-associate, while intracellularly they interact indirectly with the actin-based cytoskeleton. Several intracellular proteins termed catenins, including alpha-catenin, beta-catenin, and plakoglobin, are tightly associated with these cadherins and serve to link them to the cytoskeleton. Here, we present evidence that in fibroblasts alpha-actinin, but not vinculin, colocalizes extensively with the N-cadherin/catenin complex. This is in contrast to epithelial cells where both cytoskeletal proteins colocalize extensively with E-cadherin and catenins. We further show that alpha-actinin, but not vinculin, coimmunoprecipitates specifically with alpha- and beta-catenin from N- and E-cadherin-expressing cells, but only if alpha-catenin is present. Moreover, we show that alpha-actinin coimmunoprecipitates with the N-cadherin/catenin complex in an actin-independent manner. We therefore propose that cadherin/catenin complexes are linked to the actin cytoskeleton via a direct association between alpha-actinin and alpha-catenin.

Enhanced E-cadherin expression and increased calcium-dependent cell-cell adhesion in human T-cell leukemia virus type I Tax-expressing PC12 cells

1996 ◽  
Vol 109 (3) ◽  
pp. 609-617 ◽  
Author(s):  
I. Kitajima ◽  
K. Kawahara ◽  
N. Hanyu ◽  
H. Shin ◽  
T. Tokioka ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Pc12 Cells ◽  
Type I ◽  
Cell Leukemia Virus Type ◽  
Calcium Dependent ◽  
Tax Protein ◽  
Human T Cell ◽  
Dependent Cell ◽  
E Cadherin ◽  
Cell Cell

Human T-cell leukemia virus type I (HTLV-I) Tax protein induces the expression of host cellular genes, some of which are crucial in cell proliferation and differentiation. We examined the mechanisms by which HTLV-I Tax protein induces phenotypic changes in PC12 cells. We demonstrated that the HTLV-I Tax gene induces epithelioid changes and increases cell-cell contact in PC12 cells. No change in the expression of the neural cell adhesion molecule was observed between HTLV-I Tax-expressing PC12 cells and PC12 cells transfected with a control plasmid. However, HTLV-I Tax-expressing PC12 cells demonstrated a marked change in the abundance and distribution of E-cadherin, which was concentrated at regions of cellular contact and accompanied by changes in calcium-dependent cell adhesion. Although E-cadherin is expressed at low levels in PC12 and PC12 transfected with a control plasmid cells, the steady state level of E-cadherin in tax-expressing PC12 cells increases significantly, apparently as a result of regulation at the transcriptional level. Diminished expression of Tax protein in Tax-expressing PC12 cells exposed to antisense oligonucleotides for the Tax gene suppresses E-cadherin expression and decreases cell-cell adhesion. These findings imply that HTLV-I Tax protein enhanced E-cadherin expression modulates calcium-dependent cell-cell adhesion mechanisms.

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