scholarly journals Involvement of cell-cell adhesion in the expression of the cell cohesion molecule gp80 in Dictyostelium discoideum

1994 ◽  
Vol 107 (6) ◽  
pp. 1705-1712 ◽  
Author(s):  
L. Desbarats ◽  
S.K. Brar ◽  
C.H. Siu
Keyword(s):  
Cell Adhesion ◽  
Dictyostelium Discoideum ◽  
Binding Sites ◽  
Signal Transduction Pathway ◽  
Resistant Cell ◽  
Cell Contact ◽  
Developmental Cycle ◽  
Sensitive Cell ◽  
Cell Binding ◽  
Cell Cell

Soon after the initiation of the developmental cycle of Dictyostelium discoideum, cells acquire EDTA-sensitive cell-cell binding sites mediated by the glycoprotein gp24. Cells at the aggregation stage display a second type of cell adhesion site, the EDTA-resistant cell-cell binding sites, mediated by the glycoprotein gp80. The gene encoding gp80 is first turned on to a low basal level of expression in the preaggregation stage. At the onset of the aggregation stage, cells produce pulses of low levels of cAMP, which greatly augment the expression of gp80. To investigate the role of cell-cell adhesion in the regulation of gp80 expression, cells were developed in the presence of EDTA or carnitine to block the EDTA-sensitive cell binding sites. Alternatively, cell cohesion was disrupted by shaking low-density cultures at high shearing forces. In all three instances, gp80 was expressed at a substantially reduced level. In addition, exogenous cAMP pulses, which normally were capable of stimulating a precocious and enhanced expression of gp80, failed to restore the high level of gp80 expression. However, if the formation of cell-cell contact was permitted, exogenous cAMP pulses were able to rescue the expression of gp80 even when the cAMP signal relay was blocked. These results indicate that previous cell-cell contact, provided by the EDTA-sensitive binding sites, is required for the activation of the cAMP-mediated signal transduction pathway producing high levels of gp80 expression.

Molecular mechanisms of cell-cell interaction in Dictyostelium discoideum

1988 ◽  
Vol 66 (10) ◽  
pp. 1089-1099 ◽  
Author(s):  
Chi-Hung Siu ◽  
Lu Min Wong ◽  
Tak Yee Lam ◽  
Rajender K. Kamboj ◽  
Anthony Choi ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Binding Sites ◽  
Cell Binding ◽  
Cell Surface Glycoprotein ◽  
Stage Of Development ◽  
Tissue Organization ◽  
Surface Glycoproteins ◽  
Cell Cell

During development of the cellular slime mold Dictyostelium discoideum, cells migrate in respose to cAMP to form aggregates, which give rise to fruiting bodies consisting of two major cell types: spores and stalk cells. Multicellularity is achieved by the expression of two types of cell–cell adhesion sites. The EDTA-sensitive binding sites are expressed at the initial stage of development. At the aggregation stage, cells acquire EDTA-resistant binding sites, which are mediated by a cell-surface glycoprotein of Mr 80 000 (gp80). gp80 is preferentially associated with cell surface filopodia, which are probably involved in the initiation of contact formation between cells. Covaspheres conjugated with gp80 bind specifically to aggregation-stage cells. The binding can be inhibited by precoating cells with an anti-gp80 monoclonal antibody, thus suggesting that gp80 mediates cell-cell binding via homophilic interaction. The structure of gp80 predicted from its cDNA sequence can be divided into three major domains: a membrane anchor, a hinge, and a globular region. An analysis of fusion proteins containing different gp80 segments shows that the cell-binding activity resides in the globular region. In the postaggregation stages, gp80 is replaced by other surface glycoproteins in maintaining cell–cell adhesion. One of them has a Mr of 150 000 (gp150). Anti-gp150 antibodies have no effect on aggregation-stage cells, but they disrupt cell–cell adhesion at subsequent stages. It becomes evident that the complex phenomena of cell adhesion and tissue organization involve the participation of a number of surface glycoproteins.

Antisense RNA inactivation of gene expression of a cell-cell adhesion protein (gp64) in the cellular slime mold Polysphondylium pallidum

1996 ◽  
Vol 109 (5) ◽  
pp. 1009-1016
Author(s):  
S. Funamoto ◽  
H. Ochiai
Keyword(s):  
Gene Expression ◽  
Cell Adhesion ◽  
Antisense Rna ◽  
Resistant Cell ◽  
Cell Contact ◽  
Cellular Slime Mold ◽  
Adhesion Protein ◽  
Cell Adhesion Protein ◽  
Polysphondylium Pallidum ◽  
Cell Cell

The gp64 protein of Polysphondylium pallidum has been shown to mediate EDTA-stable cell-cell adhesion. To explore the functional role of gp64, we made an antisense RNA expression construct designed to prevent the gene expression of gp64; the construct was introduced into P. pallidum cells and the transformants were characterised. The antisense RNA-expressing clone L3mc2 which had just been harvested at the growth phase tended to re-form in aggregates smaller in size than did the parental cells in either the presence or absence of 10 mM EDTA. In contrast, 6.5-hour starved L3mc2 cells remained considerably dissociated from each other after 5 minutes gyrating, although aggregation gradually increased by 50% during a further 55 minutes gyrating in the presence of 10 mM EDTA. Correspondingly, L3mc2 lacked specifically the cell-cell adhesion protein, gp64. We therefore conclude that the gp64 protein is involved in forming the EDTA-resistant cell-cell contact. In spite of the absence of gp64, L3mc2 exhibited normal developmental processes, a fact which demonstrates that another cell-cell adhesion system exists in the development of Polysphondylium. This is the first report in which an antisense RNA technique was successfully applied to Polysphondylium.

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.

scholarly journals Changes in E-cadherin rigidity sensing regulate cell adhesion

2017 ◽  
Vol 114 (29) ◽  
pp. E5835-E5844 ◽  
Author(s):  
Caitlin Collins ◽  
Aleksandra K. Denisin ◽  
Beth L. Pruitt ◽  
W. James Nelson
Keyword(s):  
Cell Adhesion ◽  
Signaling Molecules ◽  
Membrane Dynamics ◽  
Cell Contact ◽  
Adhesion Assay ◽  
Cell Periphery ◽  
Actin Organization ◽  
Rigidity Sensing ◽  
E Cadherin ◽  
Cell Cell

Mechanical cues are sensed and transduced by cell adhesion complexes to regulate diverse cell behaviors. Extracellular matrix (ECM) rigidity sensing by integrin adhesions has been well studied, but rigidity sensing by cadherins during cell adhesion is largely unexplored. Using mechanically tunable polyacrylamide (PA) gels functionalized with the extracellular domain of E-cadherin (Ecad-Fc), we showed that E-cadherin–dependent epithelial cell adhesion was sensitive to changes in PA gel elastic modulus that produced striking differences in cell morphology, actin organization, and membrane dynamics. Traction force microscopy (TFM) revealed that cells produced the greatest tractions at the cell periphery, where distinct types of actin-based membrane protrusions formed. Cells responded to substrate rigidity by reorganizing the distribution and size of high-traction-stress regions at the cell periphery. Differences in adhesion and protrusion dynamics were mediated by balancing the activities of specific signaling molecules. Cell adhesion to a 30-kPa Ecad-Fc PA gel required Cdc42- and formin-dependent filopodia formation, whereas adhesion to a 60-kPa Ecad-Fc PA gel induced Arp2/3-dependent lamellipodial protrusions. A quantitative 3D cell–cell adhesion assay and live cell imaging of cell–cell contact formation revealed that inhibition of Cdc42, formin, and Arp2/3 activities blocked the initiation, but not the maintenance of established cell–cell adhesions. These results indicate that the same signaling molecules activated by E-cadherin rigidity sensing on PA gels contribute to actin organization and membrane dynamics during cell–cell adhesion. We hypothesize that a transition in the stiffness of E-cadherin homotypic interactions regulates actin and membrane dynamics during initial stages of cell–cell adhesion.

scholarly journals Mapping of a cell-binding domain in the cell adhesion molecule gp80 of Dictyostelium discoideum.

1988 ◽  
Vol 107 (5) ◽  
pp. 1835-1843 ◽  
Author(s):  
R K Kamboj ◽  
L M Wong ◽  
T Y Lam ◽  
C H Siu
Keyword(s):  
Cell Adhesion ◽  
Dictyostelium Discoideum ◽  
Fusion Proteins ◽  
Binding Activity ◽  
Binding Domain ◽  
Globular Domain ◽  
Cell Binding ◽  
Homophilic Interaction ◽  
A Cell ◽  
Cell Binding Domain

At the aggregation stage of Dictyostelium discoideum development, a cell surface glycoprotein of Mr 80,000 (gp80) has been found to mediate the EDTA-resistant type of cell-cell adhesion via homophilic interaction (Siu, C.-H., A. Cho, and A. H. C. Choi. 1987. J. Cell Biol. 105:2523-2533). To investigate the structure-function relationships of gp80, we have isolated full length cDNA clones for gp80 and determined the DNA sequence. The deduced structure of gp80 showed three major domains. An amino-terminal globular domain composed of the bulk of the protein is supported by a short stalk region, which is followed by a membrane anchor at the carboxy terminus. Structural analysis suggested that the cell-binding domain of gp80 resides within the globular domain near the amino terminus. To investigate the relationship of the cell-binding activity to this region of the polypeptide, three protein A/gp80 (PA80) gene fusions were constructed using the expression vector pRIT2T. These PA80 fusion proteins were assayed for their ability to bind to aggregation stage cells. Binding of 125I-labeled fusion proteins PA80I (containing the Val123 to Ile514 fragment of gp80) and PA80II (Val123 to Ala258) was dosage dependent and could be inhibited by precoating cells with the cell cohesion-blocking mAb 80L5C4. On the other hand, there was no appreciable binding of PA80III (Ile174 to Ile514) to cells. Reassociation of cells was significantly inhibited in the presence of PA80I or PA80II. In addition, 125I-labeled PA80II exhibited homophilic interaction with immobilized PA80I, PA80II, or gp80. The results of these studies lead to the mapping of a cell-binding domain in the region between Val123 and Leu173 of gp80 and provide direct evidence that the cell-binding activity of gp80 resides in the protein moiety.

E-cadherin mediated cell adhesion recruits SAP97 into the cortical cytoskeleton

1998 ◽  
Vol 111 (8) ◽  
pp. 1071-1080 ◽  
Author(s):  
S.M. Reuver ◽  
C.C. Garner
Keyword(s):  
Cell Adhesion ◽  
Model Systems ◽  
Molecular Organization ◽  
Cell Contact ◽  
Adhesion Sites ◽  
Associated Proteins ◽  
Adhesion Complex ◽  
Cortical Cytoskeleton ◽  
E Cadherin ◽  
Cell Cell

Members of the SAP family of synapse-associated proteins have recently emerged as central players in the molecular organization of synapses. In this study, we have examined the mechanism that localizes one member, SAP97, to sites of cell-cell contact. Utilizing epithelial CACO-2 cells and fibroblast L-cells as model systems, we demonstrate that SAP97 is associated with the submembranous cortical cytoskeleton at cell-cell adhesion sites. Furthermore, we show that its localization into this structure is triggered by E-cadherin. Although SAP97 can be found in an E-cadherin/catenin adhesion complex, this interaction seems to be mediated by the attachment of SAP97 to the cortical cytoskeleton. Our results are consistent with a model in which SAP97 is recruited to sites of cell-cell contact via an E-cadherin induced assembly of the cortical cytoskeleton.

Analysis of Cell‐Cell Contact Mediated by Ig Superfamily Cell Adhesion Molecules

2001 ◽  
Vol 11 (1) ◽  
Author(s):  
Peter Sonderegger ◽  
Stefan Kunz ◽  
Christoph Rader ◽  
Daniel M. Suter ◽  
Esther T. Stoeckli
Keyword(s):  
Cell Adhesion ◽  
Adhesion Molecules ◽  
Cell Adhesion Molecules ◽  
Cell Contact ◽  
Ig Superfamily ◽  
Cell Cell
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