scholarly journals EXPERIMENTAL MANIPULATION OF DESMOSOME FORMATION

1973 ◽  
Vol 56 (3) ◽  
pp. 636-646 ◽  
Author(s):  
Jane Overton
Keyword(s):  
Cell Surface ◽  
Corneal Epithelium ◽  
Fold Increase ◽  
Experimental Manipulation ◽  
Pigment Cells ◽  
Embryonic Chick ◽  
Cell Surfaces ◽  
Local Cell ◽  
Lateral Cell

In the corneal epithelium of the embryonic chick there is a 3- to 4-fold increase in desmosomes between the 15th and 16th days of incubation which has not been noted in earlier studies of this tissue. This finding has made it feasible to study the effects of the local cell environment on desmosome formation. Cells of 15-day corneas which were forming desmosomes rapidly, were dispersed and combined in culture with cells from 10-day corneas which were forming few desmosomes. Surfaces of the same 15-day cell which were confronted with either another 15-day cell or a 10-day cell were compared. Desmosomes formed preferentially on the surface adjacent to a like cell. When 15-day cells were confronted with pigment cells, desmosomes formed almost exclusively on the surface adjacent to a like cell. Evidence for such localized differences on the same cell surface emphasize the importance of the immediate cell environment in desmosome formation. The observation that single desmosome plaques form occasionally on lateral cell surfaces has been noted previously. This finding was confirmed.

Functional partitioning of beta1 integrins revealed by activating and inhibitory mAbs

1997 ◽  
Vol 110 (21) ◽  
pp. 2647-2659 ◽  
Author(s):  
M.T. Cruz ◽  
C.L. Dalgard ◽  
M.J. Ignatius
Keyword(s):  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Dermal Fibroblasts ◽  
The Other ◽  
Embryonic Chick ◽  
Cell Surfaces ◽  
Double Labeling ◽  
Focal Contacts ◽  
Functional Partitioning ◽  
Discrete Populations

Integrins exist in different activation states on the surfaces of cells. Addition of the proper signal, ligand, or antibody can alter the activation state of these molecules. We report here the identification of two immunocytochemically distinct populations of beta1 integrins on fixed embryonic chick dermal fibroblasts. One population, recognized by the integrin activating mAb TASC, localizes to discrete regions of the cell, most likely focal contacts. These integrins co-localize with other proteins, such as vinculin and F-actin, and their retention at these sites is dependent on the actin cytoskeleton. The other population, identified with the inhibitory mAb W1B10, is more evenly distributed throughout the cell surface, and its pattern remains unchanged after disruption of the actin cytoskeleton. Double labeling experiments using Fab fragments of TASC alongside whole W1B10 IgG revealed non-overlapping staining patterns. These results show that it is possible to visualize and study discrete populations of integrins on cell surfaces using two different antibodies. We hypothesize that these antibodies report differences in the distribution of receptors in two different states. A model is proposed describing the ligand independent recruitment of integrins based on these findings and results from other labs.

scholarly journals TISSUE-SPECIFIC CELL-SURFACE ANTIGENS IN EMBRYONIC CELLS

1972 ◽  
Vol 53 (2) ◽  
pp. 435-449 ◽  
Author(s):  
Irving Goldschneider ◽  
A. A. Moscona
Keyword(s):  
Cell Surface ◽  
Surface Antigens ◽  
Embryonic Cell ◽  
Specific Cell ◽  
Embryonic Chick ◽  
Embryonic Cells ◽  
Cell Surfaces ◽  
Cell Surface Antigens ◽  
Tissue Specific ◽  
High Degree

With the use of antisera prepared in rabbits against suspensions of live embryonic chick tissue cells, qualitative differences in cell surface antigens were demonstrated on cells from different embryonic chick tissues by immune agglutination and immunofluorescence. Unabsorbed antisera reacted with both homologous and nonhomologous cells; thorough absorption of the antisera with heterologous tissues removed cross-reacting antibodies, and the antisera acquired a high degree of tissue specificity. Thus, antiretina cell serum absorbed with nonretina cells or tissues, agglutinated only neural retina cells, and was shown by immunofluorescence tests to react specifically with the surface of retina cells, both in cell suspensions and in frozen tissue sections. Comparable results with antisera against cells from embryonic liver and other tissues demonstrated the existence of tissue-specific, phenotypic disparities in the antigenicities of embryonic cell surfaces, in addition to the presence of cell-surface antigens shared by certain classes of cells, and of antigens common to all cells in the embryo. The results are discussed in terms of the possible involvement of such phenotypic determinants in the specification of cell surfaces, in relation to cell recognition and developmental interactions.

Circulatory Glycan-Modifying Enzymes As Systemic Regulators In Blood Cell Development

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3686-3686
Author(s):  
Joseph Lau
Keyword(s):  
Cell Surface ◽  
Blood Cell ◽  
Conflicts Of Interest ◽  
Ex Vivo ◽  
Genetically Modified ◽  
Fold Increase ◽  
Sialic Acids ◽  
Cell Surfaces ◽  
Hematopoietic Progenitors ◽  
Hematopoietic Stem

Abstract Regulating blood cell production is crucial to meeting physiologic demands and to maintaining hematopoietic equilibrium. Elucidating the systemic factors and how they contribute to the interaction of hematopoietic progenitors with their bone marrow microenvironments is crucial to the mechanistic understanding of hematopoietic regulation and development of novel therapeutic strategies. Glycosyltransferases are enzymes that normally reside within the intracellular secretory apparatus to assemble glycans on nascent proteins and lipids in transit, but they are also present in abundance in the extracellular spaces, especially in systemic circulation. One such blood-borne enzyme is the ST6Gal-1 sialyltransferase that mediates the attachment of sialic acids in a6-linkages to glycoproteins. By virtue of their presence on cell surfaces, sialyl-glycans, which are conserved structures in mammals, occupy the critical interphase between cells and their external environment. We hypothesize that remodeling of these cell surface glycans can drastically modulate the communication of systemic cues among marrow hematopoietic cells. A mouse model genetically modified for low circulating ST6Gal-1 has increased numbers of hematopoietic progenitors, increased ability to produce inflammatory cells upon acute challenge, and faster recovery from cyclophosphamide-induced myelosuppression. In ex vivo cultures, addition of ST6Gal-1 strikingly delays expansion and differentiation of murine LSK (Linneg sca-1pos cKitpos) and human CD34pos cells. We developed a subcutaneously implantable B16-F10 model genetically modified to overexpress circulatory ST6Gal-1 (B16st6gal1). Mice bearing B16st6gal1 had >10-fold elevation in circulating ST6Gal-1 levels, accompanied by >50% reduction in marrow granulocyte and B cell populations. B16st6gal1 bearing mice also had 2-fold increase in the number of Linneg cells, suggesting a blockade in development of progenitors into end-effector cells. Murine LSK cell surfaces are decorated with a6-sialic acids but they do not endogenously express ST6Gal-1. Bone chimeras show that the a6-sialic acids on LSK surfaces require the distally synthesized ST6Gal-1 enzyme in circulation. Taken together, our data indicates the glycan-modifying enzyme, the ST6Gal-1 in circulation, is a potent systemic regulator of hematopoiesis by remodeling of cell surface glycan architecture of marrow hematopoietic stem and progenitors. (Funded by NIH Program of Excellence in Glycosciences award P01HL107146 and NIH R01AI56082) Disclosures: No relevant conflicts of interest to declare.

scholarly journals Distribution of sialoglycoconjugates on acinar cells of the mammalian pancreas.

1982 ◽  
Vol 30 (9) ◽  
pp. 947-955 ◽  
Author(s):  
V Muresan ◽  
M P Sarras ◽  
J D Jamieson
Keyword(s):  
Sialic Acid ◽  
Cell Surface ◽  
Acinar Cell ◽  
Binding Sites ◽  
Acinar Cells ◽  
Secretory Proteins ◽  
Apical Surface ◽  
Cell Surfaces ◽  
Tissue Sections ◽  
Lateral Cell

Using the sialic acid-specific lectin, limulin (LPA; from Limulus polyphemus hemolymph), the distribution and nature of sialoglycoconjugates on the surface of rat pancreatic cells has been investigated. Binding of rhodaminated LPA (Rh-LPA) or horseradish peroxidase-conjugated LPA (HRP-LPA) to fixed-frozen sections of adult rat pancreas resulted in intense linear staining of the apical surface of acinar cells with fainter staining on the basal but not the lateral cell surfaces. LPA binding was specific in that it could be abolished by 1) pretreatment of tissue sections with neuraminidase or periodic acid; 2) competition with sialic acid; and 3) incubation in Ca2+ -free buffers. Pretreatment of sections with proteases abolished LPA binding to the apical surfaces of acinar cells and also enhanced LPA binding to the lateral cell surface. Lipid extraction of sections following protease treatment markedly reduced LPA binding to the acinar cell periphery. These results suggest that LPA binding sites on the acinar cell apical surface may be primarily sialoglycoproteins, while those on the basolateral surfaces may consist in part of gangliosides. Electron microscopy of collagenase-dispersed acini exposed to HRP-LPA confirmed binding of LPA to the basal plasmalemma and, in addition, revealed staining of basal lamina when present. LPA binding to the acinar cell surface was not affected by digestion of tissue sections with hyaluronidase, heparinase, collagenase, or 6 M guanidine-HCl. Control experiments indicated that rat pancreatic secretory proteins contain undetectable amounts of sialoglycoproteins and thus that the apical localization of LPA is not due to adherent secretory proteins. Islets of Langerhans were always uniformly and heavily stained with LPA conjugates; this staining was protease insensitive. Appearance of LPA binding sites was examined on embryonic pancreatic epithelia. At day 15 of gestation, Rh-LPA stained the entire periphery of the epithelial cells, including the lateral cell surface, although more intense staining was already noted on the apical surface. This pattern persisted through day 17 of gestation, but by day 19 an adult staining pattern was observed with loss of staining of the lateral cell surfaces.

scholarly journals Cyto-friendly polymerization at cell surfaces modulates cell fate by clustering cell-surface receptors

2020 ◽  
Vol 11 (16) ◽  
pp. 4221-4225 ◽  
Author(s):  
Jing Qi ◽  
Weishuo Li ◽  
Xiaoling Xu ◽  
Feiyang Jin ◽  
Di Liu ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cell Fate ◽  
Cell Surface Receptors ◽  
Cell Surfaces ◽  
Receptor Clustering ◽  
Surface Polymerization ◽  
Surface Receptors ◽  
Anti Cd20 ◽  
In Cells

Cell-surface polymerization of anti-CD20 aptamer modified macromer to induce CD20 receptor clustering, and effectively initiate the apoptotic signals in cells.

scholarly journals Cellular localization and trafficking of tissue factor

Blood ◽  
2006 ◽  
Vol 107 (12) ◽  
pp. 4746-4753 ◽  
Author(s):  
Samir K. Mandal ◽  
Usha R. Pendurthi ◽  
L. Vijaya Mohan Rao
Keyword(s):  
Cell Surface ◽  
Tissue Factor ◽  
Cellular Localization ◽  
Factor Viia ◽  
Coagulation Cascade ◽  
Clotting Factor ◽  
Cell Surfaces ◽  
Caveolin 1 ◽  
Intracellular Compartments ◽  
Resultant Increase

AbstractTissue factor (TF) is the cellular receptor for clotting factor VIIa (FVIIa). The formation of TF-FVIIa complexes on cell surfaces triggers the activation of coagulation cascade and cell signaling. In the present study, we characterized the subcellular distribution of TF and its transport in fibroblasts by dual immunofluorescence confocal microscopy and biochemical methods. Our data show that a majority of TF resides in various intracellular compartments, predominantly in the Golgi. Tissue factor at the cell surface is localized in cholesterol-rich lipid rafts and extensively colocalized with caveolin-1. FVIIa binding to TF induces the internalization of TF. Of interest, we found that TF-FVIIa complex formation at the cell surface leads to TF mobilization from the Golgi with a resultant increase in TF expression at the cell surface. This process is dependent on FVIIa protease activity. Overall, the present data suggest a novel mechanism for TF expression at the cell surface by FVIIa. This mechanism could play an important role in hemostasis in response to vascular injury by increasing TF activity where and when it is needed.

Trimers of the fibronectin cell adhesion domain localize to actin filament bundles and undergo rearward translocation

2002 ◽  
Vol 115 (12) ◽  
pp. 2581-2590 ◽  
Author(s):  
Françoise Coussen ◽  
Daniel Choquet ◽  
Michael P. Sheetz ◽  
Harold P. Erickson
Keyword(s):  
Cell Adhesion ◽  
Fluorescence Microscopy ◽  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Fiber Bundles ◽  
Cell Surfaces ◽  
Actin Fiber ◽  
Filament Bundles ◽  
Necessary And Sufficient ◽  
Small Clusters

Previous studies have shown that small beads coated with FN7-10, a four-domain cell adhesion fragment of fibronectin, bind to cell surfaces and translocate rearward. Here we investigate whether soluble constructs containing two to five FN7-10 units might be sufficient for activity. We have produced a monomer, three forms of dimers, a trimer and a pentamer of FN7-10,on the end of spacer arms. These oligomers could bind small clusters of up to five integrins. Fluorescence microscopy showed that the trimer and pentamer bound strongly to the cell surface, and within 5 minutes were prominently localized to actin fiber bundles. Monomers and dimers showed only diffuse localization. Beads coated with a low concentration (probably one complex per bead) of trimer or pentamer showed prolonged binding and rearward translocation, presumably with the translocating actin cytskeleton. Beads containing monomer or dimer showed only brief binding and diffusive movements. We conclude that clusters of three integrin-binding ligands are necessary and sufficient for coupling to and translocating with the actin cytoskeleton.

scholarly journals Exo-enzymatic addition of diazirine-modified sialic acid to cell surfaces enables photocrosslinking of glycoproteins

2021 ◽  
Author(s):  
Nageswari Yarravarapu ◽  
Rohit Sai Reddy Konada ◽  
Narek Darabedian ◽  
Nichole J. Pedowtiz ◽  
Soumya N. Krishnamurthy ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Cell Surface ◽  
Cell Types ◽  
Cell Surfaces ◽  
Binding Interactions ◽  
Multiple Cell ◽  
Labeling Method ◽  
Cell Surface Glycoconjugates

Glycan binding often mediates extracellular macromolecular recognition events. Accurate characterization of these binding interactions can be difficult because of dissociation and scrambling that occur during purification and analysis steps. Use of photocrosslinking methods has been pursued to covalently capture glycan-dependent interactions in situ however use of metabolic glycan engineering methods to incorporate photocrosslinking sugar analogs is limited to certain cell types. Here we report an exo-enzymatic labeling method to add a diazirine-modified sialic acid (SiaDAz) to cell surface glycoconjugates. The method involves chemoenzymatic synthesis of diazirine-modified CMP-sialic acid (CMP-SiaDAz), followed by sialyltransferase-catalyzed addition of SiaDAz to desialylated cell surfaces. Cell surface SiaDAz-ylation is compatible with multiple cell types and is facilitated by endogenous extracellular sialyltransferase activity present in Daudi B cells. This method for extracellular addition of α2-6-linked SiaDAz enables UV-induced crosslinking of CD22, demonstrating the utility for covalent capture of glycan-mediated binding interactions.

scholarly journals Double-stranded DNA-scaffolded fluorescent probes for fluorescence imaging of cell-surface molecules

RSC Advances ◽  
2017 ◽  
Vol 7 (83) ◽  
pp. 52581-52587
Author(s):  
Zhanghua Liu ◽  
Yang Liu ◽  
Yanan Sun ◽  
Guo Chen ◽  
Yong Chen
Keyword(s):  
Cell Surface ◽  
Fluorescence Imaging ◽  
Fluorescent Probes ◽  
Cell Surface Molecules ◽  
Cell Surfaces ◽  
Surface Molecules ◽  
Double Stranded Dna

Double-stranded DNA-scaffolded fluorescent probes were developed for fluorescence imaging of molecules on cell surfaces.

The effect of neuraminidase- and ribonuclease-susceptible surface anionic groups on the aggregation of embryonic chick neural retina cells

1981 ◽  
Vol 51 (1) ◽  
pp. 229-240
Author(s):  
D.E. Maslow ◽  
J.P. Harlos
Keyword(s):  
Cell Surface ◽  
Surface Charge ◽  
Neural Retina ◽  
Heart Cells ◽  
Cellular Interactions ◽  
Embryonic Chick ◽  
Contact Behaviour ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Anionic Groups

The role of cell surface charge in cellular interactions has been the subject of conflicting reports. The major contribution to the net cell surface negativity of all mammalian cells studied is made by the sialic acid moieties of the surface glycoproteins, while ribonuclease-susceptible sites have been shown to contribute to the lesser extent on some cell types. Experiments were done to determine whether these anionic groups at the cell periphery affect the aggregation and sorting behaviour of embryonic chick neural retina cells when cultured alone or in combination with embryonic heart cells. The net negative surface charge density, as determined by cell electrophoretic mobility, of neuraminidase- or ribonuclease-treated cells was significantly decreased immediately after incubation with the enzymes, and the treatment with neuraminidase resulted in a reduction in the binding of colloidal iron hydroxide particles at the cell surface. Both enzymes caused reduced aggregate size in gyratory shaker cultures of neural retina and mixed cell suspensions, and fewer neural retina cells adherent to microtest plate surfaces, but no differences were seen in their histological appearance or sorting pattern in mixed shaker culture. The results indicate that the neuraminidase- and ribonuclease-susceptible groups at the periphery of embryonic neural retina cells play a role in some aspects of cell contact behaviour in ways other than reduction in net negative surface charge.

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