C-CAM (cell-CAM 105) is an adhesive cell surface glycoprotein with homophilic binding properties

1990 ◽  
Vol 96 (1) ◽  
pp. 17-25
Author(s):  
A. Tingstrom ◽  
I. Blikstad ◽  
M. Aurivillius ◽  
B. Obrink
Keyword(s):  
Cell Adhesion ◽  
Cell Surface ◽  
Surface Glycoprotein ◽  
Membrane Glycoproteins ◽  
Binding Properties ◽  
Homophilic Binding ◽  
Cell Surface Glycoprotein ◽  
Fab Fragments ◽  
Cell Cell

C-CAM (Cell-CAM 105) is a cell surface glycoprotein that is involved in cell-cell adhesion of rat hepatocytes in vitro. To elucidate the adhesion mechanism the binding properties of purified C-CAM were investigated. Using proteins immobilized on nitrocellulose it was found that radiolabeled C-CAM bound to C-CAM but not to a variety of other proteins. Partitioning in Triton X-114 showed that C-CAM has hydrophobic properties. In accordance with this, C-CAM was effectively incorporated into phosphatidylcholine liposomes by dialysis from octylglucoside-containing solutions. The C-CAM-containing liposomes bound specifically to isolated hepatocytes. This binding was blocked by Fab fragments of anti-C-CAM antibodies. Furthermore, preincubation of hepatocytes with anti-C-CAM antibodies followed by washing of the cells blocked binding of C-CAM-containing liposomes. At increasing C-CAM contents in the reconstituted liposomes a marked self-aggregation of the liposomes occurred. This aggregation was blocked by Fab fragments of anti-C-CAM antibodies and by alkaline pH. After neutralization a rapid reaggregation occurred. Neither C-CAM binding to C-CAM immobilized on nitrocellulose nor C-CAM-liposome aggregation required calcium ions. Liposomes reconstituted with C-CAM-depleted membrane glycoproteins did not self-aggregate or bind to hepatocytes. Thus, it is concluded that C-CAM can bind specifically to C-CAM in a homophilic binding reaction that does not require calcium. Accordingly, C-CAM has the potential of directly mediating cell-cell adhesion via C-CAM-C-CAM binding between adjacent cells.

scholarly journals Heterologous avian system for quantitative analysis of Syncytin-1 interaction with ASCT2 receptor

Retrovirology ◽  
2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Kryštof Štafl ◽  
Martin Trávníček ◽  
Dana Kučerová ◽  
Ľubomíra Pecnová ◽  
Veronika Krchlíková ◽  
...  
Keyword(s):  
Cell Surface ◽  
Protein Expression ◽  
Large Scale ◽  
Complex Structure ◽  
Surface Glycoprotein ◽  
Soluble Form ◽  
Cell Surface Glycoprotein ◽  
Enveloped Virus ◽  
Set Up ◽  
Cell Cell

Abstract Background Human Syncytin-1 is a placentally-expressed cell surface glycoprotein of retroviral origin. After interaction with ASCT2, its cellular receptor, Syncytin-1 triggers cell–cell fusion and formation of a multinuclear syncytiotrophoblast layer of the placenta. The ASCT2 receptor is a multi-spanning membrane protein containing a protruding extracellular part called region C, which has been suggested to be a retrovirus docking site. Precise identification of the interaction site between ASCT2 and Syncytin-1 is challenging due to the complex structure of ASCT2 protein and the background of endogenous ASCT2 gene in the mammalian genome. Chicken cells lack the endogenous background and, therefore, can be used to set up a system with surrogate expression of the ASCT2 receptor. Results We have established a retroviral heterologous chicken system for rapid and reliable assessment of ectopic human ASCT2 protein expression. Our dual-fluorescence system proved successful for large-scale screening of mutant ASCT2 proteins. Using this system, we demonstrated that progressive deletion of region C substantially decreased the amount of ASCT2 protein. In addition, we implemented quantitative assays to determine the interaction of ASCT2 with Syncytin-1 at multiple levels, which included binding of the soluble form of Syncytin-1 to ASCT2 on the cell surface and a luciferase-based assay to evaluate cell–cell fusions that were triggered by Syncytin-1. Finally, we restored the envelope function of Syncytin-1 in a replication-competent retrovirus and assessed the infection of chicken cells expressing human ASCT2 by chimeric Syncytin-1-enveloped virus. The results of the quantitative assays showed that deletion of the protruding region C did not abolish the interaction of ASCT2 with Syncytin-1. Conclusions We present here a heterologous chicken system for effective assessment of the expression of transmembrane ASCT2 protein and its interaction with Syncytin-1. The system profits from the absence of endogenous ASCT2 background and implements the quantitative assays to determine the ASCT2-Syncytin-1 interaction at several levels. Using this system, we demonstrated that the protruding region C was essential for ASCT2 protein expression, but surprisingly, not for the interaction with Syncytin-1 glycoprotein.

Cell Surface Glycoprotein CD24 Marks Bone Marrow-Derived Human Mesenchymal Stem/Stromal Cells with Reduced Proliferative and Differentiation Capacity In Vitro

2021 ◽  
Vol 30 (6) ◽  
pp. 325-336
Author(s):  
Jeroen van de Peppel ◽  
Gerben J. Schaaf ◽  
Adriana Arruda Matos ◽  
Yuan Guo ◽  
Tanja Strini ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Surface ◽  
Stromal Cells ◽  
Surface Glycoprotein ◽  
Cell Surface Glycoprotein ◽  
Differentiation Capacity

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 Galectin–glycan lattices regulate cell-surface glycoprotein organization and signalling

2008 ◽  
Vol 36 (6) ◽  
pp. 1472-1477 ◽  
Author(s):  
Omai B. Garner ◽  
Linda G. Baum
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Targeted Delivery ◽  
Cell Types ◽  
Surface Glycoprotein ◽  
Membrane Domains ◽  
Cellular Functions ◽  
Cell Surface Glycoprotein

The formation of multivalent complexes of soluble galectins with glycoprotein receptors on the plasma membrane helps to organize glycoprotein assemblies on the surface of the cell. In some cell types, this formation of galectin–glycan lattices or scaffolds is critical for organizing plasma membrane domains, such as lipid rafts, or for targeted delivery of glycoproteins to the apical or basolateral surface. Galectin–glycan lattice formation is also involved in regulating the signalling threshold of some cell-surface glycoproteins, including T-cell receptors and growth factor receptors. Finally, galectin–glycan lattices can determine receptor residency time by inhibiting endocytosis of glycoprotein receptors from the cell surface, thus modulating the magnitude or duration of signalling from the cell surface. This paper reviews recent evidence in vitro and in vivo for critical physiological and cellular functions that are regulated by galectin–glycoprotein interactions.

The major cell surface glycoprotein procyclin is a receptor for induction of a novel form of cell death in African trypanosomes in vitro

2000 ◽  
Vol 111 (2) ◽  
pp. 333-349 ◽  
Author(s):  
Terry W Pearson ◽  
Robert P Beecroft ◽  
Susan C Welburn ◽  
Stefan Ruepp ◽  
Isabel Roditi ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Surface ◽  
Surface Glycoprotein ◽  
Cell Surface Glycoprotein ◽  
African Trypanosomes

scholarly journals Regulation of slug size by the cell adhesion molecule gp80 in Dictyostelium discoideum.

1990 ◽  
Vol 1 (10) ◽  
pp. 715-729 ◽  
Author(s):  
R K Kamboj ◽  
T Y Lam ◽  
C H Siu
Keyword(s):  
Dictyostelium Discoideum ◽  
Parental Strain ◽  
Physiological Role ◽  
Resistant Cell ◽  
Surface Glycoprotein ◽  
Cell Binding ◽  
Cell Surface Glycoprotein ◽  
Cell Cell

We previously provided in vitro evidence that the cell surface glycoprotein of Mr80,000 (gp80) of Dictyostelium discoideum is capable of mediating EDTA-resistant cell-cell binding. Expression of gp80 is specific for the aggregation stage when cells form tight aggregates. To investigate the physiological role of gp80, Dictyostelium cells were transformed with a vector containing gp80 cDNA fused to an actin promoter. gp80 transcripts were detected in transformed cells in their vegetative growth phase. Transformants at this stage also exhibited EDTA-resistant cell cohesion, thus providing direct in vivo evidence that gp80 mediates cell-cell binding via homophilic interaction. While aggregates of the parental strain KAX3 had the tendency to break up to form small slugs, transformants expressing an increased amount of gp80 were able to maintain the integrity of aggregates, giving rise to larger slugs, resulting in the formation of bigger fruiting bodies. To further demonstrate that the increase in slug size could be correlated with the expression of gp80, cells of the parental strain were treated with exogenous cAMP pulses to stimulate an over-expression of gp80. The treated cells also gave rise to larger slugs, consistent with the notion that slug size is influenced by intercellular adhesiveness during development.

Identification of a cell-surface glycoprotein mediating cell adhesion in EBV-immortalized normal B cells

1986 ◽  
Vol 38 (4) ◽  
pp. 539-547 ◽  
Author(s):  
Manuel Patarroyo ◽  
Patrick G. Beatty ◽  
Kenneth Nilsson ◽  
Carl G. Gahmberg
Keyword(s):  
Cell Adhesion ◽  
B Cells ◽  
Cell Surface ◽  
Surface Glycoprotein ◽  
Cell Surface Glycoprotein ◽  
A Cell
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