scholarly journals Immunoelectron microscopic studies of the sites of cell-substratum and cell-cell contacts in cultured fibroblasts.

1982 ◽  
Vol 95 (1) ◽  
pp. 205-222 ◽  
Author(s):  
W T Chen ◽  
S J Singer
Keyword(s):  
Extracellular Matrix ◽  
The Other ◽  
Cell Contact ◽  
Narrow Gap ◽  
Frozen Sections ◽  
Cultured Fibroblasts ◽  
Contact Sites ◽  
Morphological Criteria ◽  
Extracellular Matrix Components ◽  
Cell Cell

Our object was to obtain information about the molecular structures present at cell-substratum and cell-cell contact sites formed by cultured fibroblasts. We have carried out double immunoelectron-microscopic labeling experiments on ultrathin frozen sections cut through such contact sites to determine the absolute and relative dispositions of the three proteins fibronectin, vinculin, and alpha-actinin with respect to these sites. (a) Three types of cell-substratum and cell-cell contact sites familiar from plastic sections could also be discriminated in the frozen sections by morphological criteria alone, i.e., the gap distances between the two surfaces, and the presence of submembranous densities. These types were: (i) focal adhesions (FA); (ii) close contacts (CC); and (iii) extracellular matrix contacts (ECM). This morphological typing of the contact sites allowed us to recognize and assign distinctive immunolabeling patterns for the three proteins to each type of site on the frozen sections. (b) FA sites were immunolabeled intracellularly for vinculin and alpha-actinin, with vinculin labeling situated closer to the membrane than alpha-actinin. Fibronectin was not labeled in the narrow gap between the cell surface and the substratum, or between two cells, at FA sites. Control experiments showed that this could not be ascribed to inaccessibility of the FA narrow gap to the immunolabeling reagents but indicated an absence or severe depletion of fibronectin from these sites. (c) CC sites were labeled intracellularly for alpha-actinin but not vinculin and were labeled extracellularly for fibronectin. (d) ECM sites were characterized by large separations (often greater than 100 nm) between the cell and substratum or between two cells, which were connected by long cables of extracellular matrix components, including fibronectin. In late (24-36 h) cultures, ECM contacts predominated over the other types. ECM sites appeared to be of two kinds, one labeled intracellularly for both alpha-actinin and vinculin, the other for alpha-actinin alone. (e) From these and other results, a coherent but tentative scheme is proposed for the molecular ultrastructure of these contacts sites, and specific functional roles are suggested for fibronectin, vinculin, and alpha-actinin in cell adhesion and in the linkage of intracellular microfilaments to membranes at the different types of contact sites.

The localized assembly of extracellular matrix integrin ligands requires cell-cell contact

2000 ◽  
Vol 113 (21) ◽  
pp. 3715-3723 ◽  
Author(s):  
M.D. Martin-Bermudo ◽  
N.H. Brown
Keyword(s):  
Extracellular Matrix ◽  
Drosophila Embryo ◽  
Cell Contact ◽  
Primary Role ◽  
Dependent Manner ◽  
Muscle Attachment ◽  
Matrix Assembly ◽  
Attachment Sites ◽  
Genetically Manipulated ◽  
Cell Cell

The assembly of an organism requires the interaction between different layers of cells, in many cases via an extracellular matrix. In the developing Drosophila larva, muscles attach in an integrin-dependent manner to the epidermis, via a specialized extracellular matrix called tendon matrix. Tiggrin, a tendon matrix integrin ligand, is primarily synthesized by cells distant to the muscle attachment sites, yet it accumulates specifically at these sites. Previous work has shown that the PS integrins are not required for tiggrin localization, suggesting that there is redundancy among tiggrin receptors. We have examined this by testing whether the PS2 integrin can recruit tiggrin to ectopic locations within the Drosophila embryo. We found that neither the wild type nor modified forms of the PS2 integrin, which have higher affinity for tiggrin, can recruit tiggrin to new cellular contexts. Next, we genetically manipulated the fate of the muscles and the epidermal muscle attachment cells, which demonstrated that muscles have the primary role in recruiting tiggrin to the tendon matrix and that cell-cell contact is necessary for this recruitment. Thus we propose that the inherent polarity of the muscle cells leads to a molecular specialization of their ends, and interactions between the ends produces an integrin-independent tiggrin receptor. Thus, interaction between cells generates an extracellular environment capable of nucleating extracellular matrix assembly.

scholarly journals Integrin VLA-3: ultrastructural localization at cell-cell contact sites of human cell cultures.

1989 ◽  
Vol 109 (4) ◽  
pp. 1807-1815 ◽  
Author(s):  
R Kaufmann ◽  
D Frösch ◽  
C Westphal ◽  
L Weber ◽  
C E Klein
Keyword(s):  
Human Cell ◽  
Cultured Cells ◽  
Cell Types ◽  
Cell Surface Receptor ◽  
Cell Contact ◽  
Type I ◽  
Intercellular Contact ◽  
Basal Cells ◽  
Contact Sites ◽  
Cell Cell

The integrin VLA-3 is a cell surface receptor, which binds to fibronectin, laminin, collagen type I and VI (Takada, Y., E. A. Wayner, W. G. Carter, and M. E. Hemler. 1988. J. Cell. Biochem. 37:385-393) and is highly expressed in substrate adherent cultures of almost all human cell types. The ligand specificity of VLA-3 and the inhibition of cell adhesion by anti-VLA-3 monoclonal antibodies suggest its involvement in cell-substrate interaction. In normal tissues, VLA-3 is restricted to few cell types, notably the kidney glomeruli and basal cells of the epidermis. In the epidermis, VLA-3 is generally strongly expressed on the entire plasma membrane of basal cells and is not polarized towards the basement membrane (Klein, C. E., C. Cardon-Cardo, R. Soehnchen, R. J. Cote, H. F. Oettgen, M. Eisinger, and L. J. Old. 1987. J. Invest. Dermatol. 89:500-507). Based on this finding we speculated that, in addition to a role of VLA-3 for adhesion of cells to substrate, it could also be relevant for cell-cell interaction. To investigate this, we ultrastructurally localized VLA-3 on the surface of cultured cells by immunoelectron microscopy. In accordance with our concept, we found VLA-3 strongly associated with intercellular contact sites. Interestingly, very little immunoreactivity was detected at the under-surface of cells which had been cultured for 18-32 h. This observation was unexpected but is consistent with previous findings (Kantor, R. R. S., M. J. Mattes, K. D. Lloyd, L. J. Old, and A. P. Albino. 1987. J. Biol. Chem. 262:15158-15165) which suggest that the association of VLA-3 with the basal surface of substrate adherent tumor cells is a late event occurring after days of culture under confluent conditions. However, we cannot formally rule out VLA-3 expression at the undersurface of cells under our experimental conditions, since VLA-3 molecules at this location could be inaccessible for in situ labeling of unfixed cells because of spatial interferences. In conclusion, our results demonstrate the expression of VLA-3 at intercellular contact sites of cultured cells supporting the concept that it may be relevant for intercellular interactions also.

scholarly journals A plasma membrane protein is involved in cell contact-mediated regulation of tissue-specific genes in adult hepatocytes.

1991 ◽  
Vol 115 (2) ◽  
pp. 505-515 ◽  
Author(s):  
A Corlu ◽  
B Kneip ◽  
C Lhadi ◽  
G Leray ◽  
D Glaise ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Membrane Protein ◽  
Plasma Membranes ◽  
Surface Protein ◽  
Cell Aggregation ◽  
Cell Interaction ◽  
Cell Contact ◽  
Plasma Membrane Protein ◽  
Extracellular Matrix Components

We have identified the liver-regulating protein (LRP), a cell surface protein involved in the maintenance of hepatocyte differentiation when cocultured with rat liver epithelial cells (RLEC). LRP was defined by immunoreactivity to a monoclonal antibody (mAb L8) prepared from RLEC. mAb L8 specifically detected two polypeptides of 85 and 73 kD in immunoprecipitation of both hepatocyte- and RLEC-iodinated plasma membranes. The involvement of these polypeptides, which are integral membrane proteins, in cell interaction-mediated regulation of hepatocytes was assessed by evaluating the perturbing effects of the antibody on cocultures with RLEC. Several parameters characteristic of differentiated hepatocytes were studied, such as liver-specific and house-keeping gene expression, cytoskeletal organization and deposition of extracellular matrix (ECM). An early cytoskeletal disturbance was evidenced and a marked alteration of hepatocyte functional capacity was observed in the presence of the antibody, together with a loss of ECM deposition. By contrast, cell-cell aggregation or cell adhesion to various extracellular matrix components were not affected. These findings suggest that LRP is distinct from an extracellular matrix receptor. The fact that early addition of mAb L8 during cell contact establishment was necessary to be effective may indicate that LRP is a novel plasma membrane protein that plays an early pivotal role in the coordinated metabolic changes which lead to the differentiated phenotype of mature hepatocytes.

scholarly journals The influence of peptide bioregulators on skin aging in 3D culture model

2016 ◽  
Vol 19 (1) ◽  
pp. 58-63 ◽  
Author(s):  
K. V Kozhina ◽  
E. N Volkova ◽  
I. N Saburina ◽  
Sergey G. Morozov ◽  
I. M Zurina ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Matrix Protein ◽  
3D Culture ◽  
Dermal Fibroblasts ◽  
Extracellular Matrix Protein ◽  
Cytokeratin 19 ◽  
Collagen Type Iv ◽  
Cultured Fibroblasts ◽  
Study Results ◽  
Extracellular Matrix Components

He effect of mesotherapy injection (Meso-Wharton R199TM) on the dermal fibroblasts culture, simulating condition of (mature) aging skin cells are studied. Material and methods. The culture of 4th passage fibroblasts (P4), that corresponds to young skin fibroblasts (control) and the culture of 18th passage fibroblasts (P18), that has all the signs of aging dermal fibroblasts (predominance of large cells, slow cell division) were used. Bioactivity was assessed by cell morphology, epithelium-mesenchyme plasticity and expression of fibroblasts markers: cytokeratin 19, elastin, a-smooth muscle actin (aSMA), PCNA (proliferation marker), collagen types I, III, IV and fibronectin. The formation of spheroids occur when fibroblasts P18 are cultivating with the injection medication, on terms comparable to the formation of spheroids from P4 young fibroblasts. From culture of fibroblasts P18, that was cultured without medication, does not form the full spheroid, but aggregation of cells and their gradual destruction with necrotic masses within the unit are observed. The presence of the medication stimulates the “rejuvenation” of cells and subsequent recovery of the mesenchyme-epithelial plasticity of cultured fibroblasts due to the reduced ability to synthesize sufficient to establish the amount of intercellular contacts the extracellular matrix components (fibronectin and collagen), which affects the ability to form spheroids. Culturing spheroids formed with the medication stimulates expression of elastin, collagen type IV, fibronectin extracellular matrix protein that supports the skin elasticity and superficial cells actively express cytokeratin 19. The study results clearly demonstrate the effectiveness of mesotherapeutic treatment for skin rejuvenation.

scholarly journals The role of spectrin in cell adhesion and cell–cell contact

2019 ◽  
Vol 244 (15) ◽  
pp. 1303-1312 ◽  
Author(s):  
Beata Machnicka ◽  
Renata Grochowalska ◽  
Dżamila M Bogusławska ◽  
Aleksander F Sikorski
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Cell Surface ◽  
Cell Biology ◽  
Membrane Integrity ◽  
Cell Contact ◽  
Surface Activities ◽  
New Findings ◽  
Cell Cell

Spectrins are proteins that are responsible for many aspects of cell function and adaptation to changing environments. Primarily the spectrin-based membrane skeleton maintains cell membrane integrity and its mechanical properties, together with the cytoskeletal network a support cell shape. The occurrence of a variety of spectrin isoforms in diverse cellular environments indicates that it is a multifunctional protein involved in numerous physiological pathways. Participation of spectrin in cell–cell and cell–extracellular matrix adhesion and formation of dynamic plasma membrane protrusions and associated signaling events is a subject of interest for researchers in the fields of cell biology and molecular medicine. In this mini-review, we focus on data concerning the role of spectrins in cell surface activities such as adhesion, cell–cell contact, and invadosome formation. We discuss data on different adhesion proteins that directly or indirectly interact with spectrin repeats. New findings support the involvement of spectrin in cell adhesion and spreading, formation of lamellipodia, and also the participation in morphogenetic processes, such as eye development, oogenesis, and angiogenesis. Here, we review the role of spectrin in cell adhesion and cell–cell contact.Impact statementThis article reviews properties of spectrins as a group of proteins involved in cell surface activities such as, adhesion and cell–cell contact, and their contribution to morphogenesis. We show a new area of research and discuss the involvement of spectrin in regulation of cell–cell contact leading to immunological synapse formation and in shaping synapse architecture during myoblast fusion. Data indicate involvement of spectrins in adhesion and cell–cell or cell–extracellular matrix interactions and therefore in signaling pathways. There is evidence of spectrin’s contribution to the processes of morphogenesis which are connected to its interactions with adhesion molecules, membrane proteins (and perhaps lipids), and actin. Our aim was to highlight the essential role of spectrin in cell–cell contact and cell adhesion.

scholarly journals Afadin is localized at cell–cell contact sites in mesangial cells and regulates migratory polarity

2015 ◽  
Vol 96 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Haruko Tsurumi ◽  
Hidetake Kurihara ◽  
Kenichiro Miura ◽  
Atsushi Tanego ◽  
Yasutaka Ohta ◽  
...  
Keyword(s):  
Mesangial Cells ◽  
Cell Contact ◽  
Contact Sites ◽  
Cell Cell

scholarly journals Development of cell surface linkage complexes in cultured fibroblasts.

1985 ◽  
Vol 100 (4) ◽  
pp. 1103-1114 ◽  
Author(s):  
W T Chen ◽  
E Hasegawa ◽  
T Hasegawa ◽  
C Weinstock ◽  
K M Yamada
Keyword(s):  
Monoclonal Antibody ◽  
Extracellular Matrix ◽  
Cell Surface ◽  
Protein Complex ◽  
Cell Attachment ◽  
Embryonic Fibroblasts ◽  
Cultured Fibroblasts ◽  
Contact Sites ◽  
Adhesion Sites ◽  
Microfilament Bundles

The possible role of a 140K membrane-associated protein complex (140K) in fibronectin-cytoskeleton associations has been examined. The 140K was identified by the monoclonal antibody JG22E. Monoclonal and polyclonal antibodies to the 140K showed identical patterns of binding to the cell membranes of fixed and permeabilized chicken embryonic fibroblasts; localization was diffuse, but with marked concentration in cell-to-extracellular matrix contact sites. Correlative localization with interference reflection microscopy and double-label or triple-label immunofluorescence showed that 140K co-distributed with extracellular fibronectin fibrils and intracellular alpha-actinin in microfilament bundles at extracellular matrix contact sites but tended not to co-localize with tropomyosin present in bundles at sites farther from adhesion sites. In addition, binding of antibodies to 140K, alpha-actinin, and fibronectin was excluded from vinculin-rich focal adhesion sites at the cellular periphery. A progressive development of cell surface alpha-actinin-140K-fibronectin associations was observed in early spreading cells. The anti-140K monoclonal antibody JG22E inhibited the attachment and spreading of both normal and Rous sarcoma virus-transformed chicken embryonic fibroblasts to a fibronectin substratum. However, the anti-140K monoclonal antibody became a positive mediator of cell attachment and spreading if it was adsorbed or cross-linked to the substratum. Our results provide the first description of a membrane-associated protein complex that co-localizes with fibronectin and microfilament bundles, and they suggest that the 140K complex may be part of a cell surface linkage between fibronectin and the cytoskeleton.

scholarly journals Rab35 regulates cadherin-mediated adherens junction formation and myoblast fusion

2013 ◽  
Vol 24 (3) ◽  
pp. 234-245 ◽  
Author(s):  
Sophie Charrasse ◽  
Franck Comunale ◽  
Sylvain De Rossi ◽  
Arnaud Echard ◽  
Cécile Gauthier-Rouvière
Keyword(s):  
Adherens Junction ◽  
Phosphatidyl Inositol ◽  
Myoblast Fusion ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Cell Contact ◽  
Dependent Manner ◽  
Cell Contacts ◽  
Contact Sites ◽  
Cell Cell

Cadherins are homophilic cell–cell adhesion molecules implicated in many fundamental processes, such as morphogenesis, cell growth, and differentiation. They accumulate at cell–cell contact sites and assemble into large macromolecular complexes named adherens junctions (AJs). Cadherin targeting and function are regulated by various cellular processes, many players of which remain to be uncovered. Here we identify the small GTPase Rab35 as a new regulator of cadherin trafficking and stabilization at cell–cell contacts in C2C12 myoblasts and HeLa cells. We find that Rab35 accumulates at cell–cell contacts in a cadherin-dependent manner. Knockdown of Rab35 or expression of a dominant-negative form of Rab35 impaired N- and M-cadherin recruitment to cell–cell contacts, their stabilization at the plasma membrane, and association with p120 catenin and led to their accumulation in transferrin-, clathrin-, and AP-2–positive intracellular vesicles. We also find that Rab35 function is required for PIP5KIγ accumulation at cell–cell contacts and phosphatidyl inositol 4,5-bisphosphate production, which is involved in cadherin stabilization at contact sites. Finally, we show that Rab35 regulates myoblast fusion, a major cellular process under the control of cadherin-dependent signaling. Taken together, these results reveal that Rab35 regulates cadherin-dependent AJ formation and myoblast fusion.

scholarly journals Different effects of dominant negative mutants of desmocollin and desmoglein on the cell-cell adhesion of keratinocytes

2000 ◽  
Vol 113 (10) ◽  
pp. 1803-1811
Author(s):  
Y. Hanakawa ◽  
M. Amagai ◽  
Y. Shirakata ◽  
K. Sayama ◽  
K. Hashimoto
Keyword(s):  
Cell Adhesion ◽  
Adherens Junctions ◽  
Dominant Negative ◽  
Cell Contact ◽  
Beta Catenin ◽  
Hacat Cells ◽  
Subsequent Formation ◽  
Contact Sites ◽  
E Cadherin ◽  
Cell Cell

Desmosomes contain two types of cadherin: desmocollin (Dsc) and desmoglein (Dsg). In this study, we examined the different roles that Dsc and Dsg play in the formation of desmosomes, by using dominant-negative mutants. We constructed recombinant adenoviruses (Ad) containing truncated mutants of E-cadherin, desmocollin 3a, and desmoglein 3 lacking a large part of their extracellular domains (EcaddeltaEC, Dsc3adeltaEC, Dsg3deltaEC), using the Cre-loxP Ad system to circumvent the problem of the toxicity of the mutants to virus-producing cells. When Dsc3adeltaEC Ad-infected HaCaT cells were cultured with high levels of calcium, E-cadherin and beta-catenin, which are marker molecules for the adherens junction, disappeared from the cell-cell contact sites, and cell-cell adhesion was disrupted. This also occurred in the cells infected with EcaddeltaEC Ad. With Dsg3deltaEC Ad infection, keratin insertion at the cell-cell contact sites was inhibited and desmoplakin, a marker of desmosomes, was stained in perinuclear dots while the adherens junctions remained intact. Dsc3adeltaEC Ad inhibited the induction of adherens junctions and the subsequent formation of desmosomes with the calcium shift, while Dsg3deltaEC Ad only inhibited the formation of desmosomes. To further determine whether Dsc3adeltaEC directly affected adherens junctions, mouse fibroblast L cells transfected with E-cadherin (LEC5) were infected with these mutant Ads. Both Dsc3adeltaEC and EcaddeltaEC inhibited the cell-cell adhesion of LEC5 cells, as determined by the cell aggregation assay, while Dsg3deltaEC did not. These results indicate that the dominant negative effects of Dsg3deltaEC were restricted to desmosomes, while those of Dsc3adeltaEC were observed in both desmosomes and adherens junctions. Furthermore, the cytoplasmic domain of Dsc3adeltaEC coprecipitated both plakoglobin and beta-catenin in HaCaT cells. In addition, beta-catenin was found to bind the endogenous Dsc in HaCaT cells. These findings lead us to speculate that Dsc interacts with components of the adherens junctions through beta-catenin, and plays a role in nucleating desmosomes after the adherens junctions have been established.

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