scholarly journals Synthesis and shedding of hyaluronan from plasma membranes of human fibroblasts and metastatic and non-metastatic melanoma cells

1999 ◽  
Vol 343 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Hans-Joachim LüKE ◽  
Peter PREHM
Keyword(s):  
Cell Surface ◽  
Plasma Membranes ◽  
Human Fibroblasts ◽  
Metastatic Potential ◽  
Melanoma Cells ◽  
High Molecular Mass ◽  
Chain Elongation ◽  
Hyaluronan Synthase ◽  
Surface Receptors ◽  
Melanoma Cell Lines

The regulation of hyaluronan synthesis and shedding was analysed in human fibroblasts and in two melanoma cells that differed in the metastatic potential and proteolysis of the hyaluronan receptor CD44. Dissociation of nascent hyaluronan from plasma membranes isolated from fibroblasts by high salt concentrations led to activation of hyaluronan synthase. Hyaluronan synthesis was also enhanced in plasma membranes from fibroblasts that had been treated with hyaluronidase or trypsin. Hyaluronan oligosaccharides stimulated hyaluronan production in fibroblast cultures. These results indicated that nascent high-molecular-mass hyaluronan inhibited its own chain elongation, if it was retained in the vicinity of the synthase by cell-surface receptors. The results also indicated that increased hyaluronan synthesis and shedding correlated with proteolysis of CD44 on the melanoma cell lines, which has been observed by others.

scholarly journals Membrane distribution and adsorptive endocytosis by C3b receptors on human polymorphonuclear leukocytes.

1981 ◽  
Vol 153 (6) ◽  
pp. 1615-1628 ◽  
Author(s):  
D T Fearon ◽  
I Kaneko ◽  
G G Thomson
Keyword(s):  
Cell Surface ◽  
Polymorphonuclear Leukocytes ◽  
Plasma Membranes ◽  
Antibody Fragment ◽  
Cell Receptor ◽  
Molar Ratio ◽  
Surface Receptors ◽  
C3b Receptor ◽  
Tetramethylrhodamine Isothiocyanate ◽  
Human Polymorphonuclear Leukocytes

C3b receptors on human polymorphonuclear leukocytes (PMN) were nonrandomly distributed in small clusters on the plasma membranes of these cells when assessed by indirect immunofluorescence at 0 degree C using monospecific rabbit Fab' or F(ab')2 anti-C3b receptor and tetramethylrhodamine isothiocyanate (TRITC)-conjugated goat IgG anti-F(ab')2. When PMN were incubated with the bivalent anti-C3b receptor at 37 rather than at 0 degree C, almost no immunofluorescence was observed, which indicates that the C3b receptor-F(ab')2 complexes had been rendered inaccessible to TRITC-IgG anti-F(ab')2. Endocytosis of the anti-C3b receptor ligand was quantitated by measuring the binding 131I-IgG anti-F(ab')2 by PMN that had previously taken up 125I-F(ab')2 anti-C3b receptor at 0 and at 37 degree C, respectively. There was a constant 2: 1 molar ratio of anti-F(ab')2 to anti-C3b receptor with PMN that had been incubated with the first antibody at 0 degree C. In contrast, when increments of F(ab')2 anti-C3b receptor were taken up by the cells at 37 degree C, there was a dose-related decline in this molar ratio to a minimum of 0.2 molecules of anti-F(ab')2 anti-F(ab')2 bound per molecule of PMN-associated anti-C3b receptor. 125I-F(ab')2 anti-C3b receptor taken up by PMN at 37 degree C was also inaccessible to release by proteolytic treatment of the cells with pronase. The rate of endocytosis of 125I-F(ab')2 anti-C3b receptor was rapid as the PMN-bound antibody fragment became inaccessible to 131I-IgG anti-F(ab')2 within 10 min during incubation of the cells at 37 degree C. In contrast to these findings, 125I-Fab' anti-C3b receptor that was taken up by PMN at 37 degree C remained accessible to both 131I-IgG anti-F(ab')2 and to proteolytic release by pronase, which suggests that monovalent interaction of ligand with C3b receptors was not sufficient for induction of endocytosis. The requirement for multivalency was also demonstrated using the C3b-OR, the normal ligand for the C3b receptor. 125I-C3b-OR was specifically bound by PMN but remained on the cell receptor. 125I-C3b-OR was specifically bound by PMN but remained on the cell surface, as determined by its accessibility to pronase, unless it was cross-linked with F(ab')2 anti-C3. Although C3b receptors on PMN do not mediate internalization of adsorptive pinocytosis of soluble ligand indicates their potential for the clearance of C3b-bearing immune complexes without recruitment of other cell surface receptors.

scholarly journals Glycosaminoglycans on fibroblasts accelerate thrombin inhibition by protease nexin-1

1987 ◽  
Vol 245 (2) ◽  
pp. 543-550 ◽  
Author(s):  
D H Farrell ◽  
D D Cunningham
Keyword(s):  
Complex Formation ◽  
Cell Surface ◽  
Plasma Membranes ◽  
Chondroitin Sulphate ◽  
Human Fibroblasts ◽  
Heparan Sulphate ◽  
Order Rate Constant ◽  
Subsequent Treatment ◽  
Protease Nexin ◽  
Inhibition Of Thrombin

Protease nexin-1 (PN-1) is a proteinase inhibitor that is secreted by human fibroblasts in culture. PN-1 inhibits certain regulatory serine proteinases by forming a covalent complex with the catalytic-site serine residue; the complex then binds to the cell surface and is internalized and degraded. The fibroblast surface was recently shown to accelerate the rate of complex-formation between PN-1 and thrombin. The present paper demonstrates that the accelerative activity is primarily due to cell-surface heparan sulphate, with a much smaller contribution from chondroitin sulphate. This conclusion is supported by the effects of purified glycosaminoglycans on the second-order rate constant for the inhibition of thrombin by PN-1. Also, treatment of 35SO4(2-)-labelled cells with heparitin sulphate lyase or chondroitin sulphate ABC lyase demonstrated two discrete pools of 35S-labelled glycosaminoglycans; subsequent treatment of plasma membranes with these glycosidases showed that heparitin sulphate lyase treatment abolished about 80% of the accelerative activity and chondroitin sulphate ABC lyase removed the remaining 20%. These results show that two components are responsible for the acceleration of PN-1-thrombin complex-formation by human fibroblasts. Although dermatan sulphate is also present on fibroblasts, it did not accelerate the inhibition of thrombin by PN-1.

Cobalamin transport proteins and their cell-surface receptors

2003 ◽  
Vol 5 (18) ◽  
pp. 1-18 ◽  
Author(s):  
Bellur Seetharam ◽  
Raghunatha R. Yammani
Keyword(s):  
Cell Surface ◽  
Blood Cells ◽  
Plasma Membranes ◽  
Intrinsic Factor ◽  
Transport Proteins ◽  
Cell Surface Receptors ◽  
Vitamin B ◽  
Cellular Transport ◽  
Surface Receptors ◽  
Molecular Aspects

The primary function of cobalamin (Cbl; vitamin B12) is the formation of red blood cells and the maintenance of a healthy nervous system. Before cells can utilise dietary Cbl, the vitamin must undergo cellular transport using two distinct receptor-mediated events. First, dietary Cbl bound to gastric intrinsic factor (IF) is taken up from the apical pole of ileal epithelial cells via a 460 kDa receptor, cubilin, and is transported across the cell bound to another Cbl-binding protein, transcobalamin II (TC II). Second, plasma TC II–Cbl is taken up by cells that need Cbl via the TC II receptor (TC II-R), a 62 kDa protein that is expressed as a functional dimer in cellular plasma membranes. Human Cbl deficiency can develop as a result of acquired or inherited dysfunction in either of these two transmembrane transport events. This review focuses on the biochemical, cellular and molecular aspects of IF and TC II and their cell-surface receptors.

scholarly journals Cell-cycle analysis of insulin binding and internalization on mouse melanoma cells.

1981 ◽  
Vol 88 (1) ◽  
pp. 241-244 ◽  
Author(s):  
N Shimizu ◽  
Y Shimizu ◽  
B B Fuller
Keyword(s):  
Cell Cycle ◽  
Cell Surface ◽  
Insulin Binding ◽  
Melanoma Cells ◽  
Binding Activity ◽  
S Phase ◽  
Cell Cycle Analysis ◽  
Surface Receptors ◽  
Mouse Melanoma ◽  
Melanocyte Stimulating Hormone

Binding of 125I-labeled insulin to the surface receptors of Cloudman S-91 mouse melanoma cells (CCL 53.1) was studied at various phases (M, G1, S, and G2) in the cell cycle. Insulin-binding activity was persistently present during the cell cycle but the highest activity was noted at the S-phase. The insulin once bound to the cell surface receptors at any phase of the cell cycle was internalized and degraded, presumably through a lysosomal pathway. Insulin-indexing activity of melanoma cells was not affected by melanocyte-stimulating hormone.

scholarly journals Migration of highly aggressive melanoma cells on hyaluronic acid is associated with functional changes, increased turnover and shedding of CD44 receptors

1996 ◽  
Vol 109 (7) ◽  
pp. 1957-1964 ◽  
Author(s):  
M. Goebeler ◽  
D. Kaufmann ◽  
E.B. Brocker ◽  
C.E. Klein
Keyword(s):  
Hyaluronic Acid ◽  
Cell Lines ◽  
Melanoma Cell ◽  
Malignant Tumors ◽  
Standard Form ◽  
Metastatic Potential ◽  
Melanoma Cells ◽  
Functional Changes ◽  
Local Progression ◽  
Melanoma Cell Lines

Recent evidence indicates that CD44, a multifunctional adhesion receptor involved in cell-cell as well as in cell-matrix interactions, plays an important role in local progression and metastasis of malignant tumors. We have studied a set of human melanoma cell lines differing in their metastatic potential in nude mice as well as in normal melanocytes for changes in CD44 expression and function. All melanocytes and melanoma cell lines tested highly expressed the CD44 standard form (CD44s, 85 kDa) but variants at low levels only. With respect to one of the CD44-associated functions primarily involved in tumor progression we found that two highly metastatic tumor cell lines, MV3 and BLM, showed fivefold higher migration rates towards hyaluronate than melanomas with low metastatic potential and normal melanocytes. Moreover, the highly metastatic cell lines expressed four- to sixfold higher levels of the CD44 epitope involved in hyaluronic acid-binding (monoclonal antibody Hermes-1) than less aggressive melanomas and melanocytes. Hermes-1 efficiently blocked haptotaxis to hyaluronate, supporting the functional relevance of this epitope. In contrast, expression levels of other CD44s epitopes recognized by seven different anti-CD44 monoclonal antibodies were unchanged, suggesting that the migratory behaviour of the cells depends on the formation of the hyaluronate-binding Hermes-1 epitope rather than on the overall CD44s surface expression, which was virtually identical in all melanoma and melanocyte cell lines tested. Differences in the accessibility of the hyaluronate-binding epitope defined by Hermes-1 correlated with the phosphorylation state of CD44s, probably reflecting different activation states of the receptor. Furthermore, immunoprecipitation and pulse/chase studies revealed a three- to fivefold increase in CD44 synthesis in the highly aggressive melanoma cells as compared to the other cell lines and the melanocytes, indicating a reduction of CD44 half-life and up-regulation of turnover. Moreover, highly aggressive melanoma cell lines were found to shed significant amounts of CD44 from the cell surface and to secrete its ligand hyaluronic acid, which may refer to an “autocrine' mechanism mediating melanoma cell motility.

scholarly journals Association of cell surface receptors for melanotropin with the Golgi region in mouse melanoma cells.

1976 ◽  
Vol 73 (2) ◽  
pp. 559-562 ◽  
Author(s):  
J. M. Varga ◽  
G. Moellmann ◽  
P. Fritsch ◽  
E. Godawska ◽  
A. B. Lerner
Keyword(s):  
Cell Surface ◽  
Melanoma Cells ◽  
Cell Surface Receptors ◽  
Surface Receptors ◽  
Mouse Melanoma ◽  
Golgi Region

scholarly journals Linkage of extracellular plasminogen activator to the fibroblast cytoskeleton: colocalization of cell surface urokinase with vinculin.

1988 ◽  
Vol 106 (4) ◽  
pp. 1241-1247 ◽  
Author(s):  
C A Hébert ◽  
J B Baker
Keyword(s):  
Cell Surface ◽  
Binding Sites ◽  
Plasma Membranes ◽  
Human Fibroblasts ◽  
Cell Types ◽  
Actin Binding ◽  
Double Labeling ◽  
Amino Acid Peptide ◽  
Adhesion Sites ◽  
Fibrosarcoma Cells

Several cell types display binding sites for [125I]urokinase (Vassalli, J.-D., D. Baccino, D. Belin. 1985. J. Cell Biol. 100:86-92) which in certain cases are occupied with endogenous urokinase. These sites appear to focus urokinase at cell surfaces and hence may participate in tissue matrix destruction and cell invasion. Recently Pöllänen et al. (1987) demonstrated that the cell surface urokinase of human fibroblasts and fibrosarcoma cells is deposited underneath the cells in strands, apparently at sites of cell-to-substratum contact. Here, using immunofluorescence double labeling, we show that the urokinase strands present on human foreskin fibroblasts are colocalized with strands of vinculin, an intracellular actin-binding protein that is deposited at cell-to-substratum focal adhesion sites. Thus, this indicates linkage of the plasminogen/plasmin system both to sites of cell adhesion and to the cytoskeleton. The urokinase strands on HT 1080 fibrosarcoma cells are more numerous and have shapes that are more tortuous than those on normal fibroblasts. In intact HT 1080 cells, colocalized vinculin strands are obscured by an intense background of soluble vinculin but are apparent on isolated ventral plasma membranes. Certain properties of the urokinase strands suggest that they are related to the [125I]urokinase-binding sites that have been described by several groups: (a) incubating fibroblasts with dexamethasone for 48 h or at pH 3 at 5 degrees C for 10 min greatly decreases the number and intensity of the urokinase strands; (b) strands reappear when glucocorticoid-treated cells are incubated with exogenous 54-kD (but not 35-kD) urokinase, and this process is inhibited by a previously described 16-amino acid peptide that blocks [125I]urokinase binding to the cells.

scholarly journals Unraveling nanotopography of cell surface receptors

2019 ◽  
Author(s):  
Christian Franke ◽  
Tomas Chum ◽  
Zuzana Kvicalova ◽  
Daniela Glatzova ◽  
Alvaro Rodriguez ◽  
...  
Keyword(s):  
Cell Surface ◽  
Single Molecule ◽  
Plasma Membranes ◽  
Immobilized Cells ◽  
Complex Surface ◽  
Protein Distribution ◽  
Detection Scheme ◽  
Surface Receptors ◽  
Membrane Morphology ◽  
Simplified Algorithm

Cells communicate with their environment via surface receptors, but nanoscopic receptor organization with respect to complex cell surface morphology remains unclear. This is mainly due to a lack of accessible, robust and high-resolution methods. Here, we present an approach for mapping the topography of receptors at the cell surface with nanometer precision. The method involves coating glass coverslips with glycine, which preserves the fine membrane morphology while allowing immobilized cells to be positioned close to the optical surface. We developed an advanced and simplified algorithm for the analysis of single-molecule localization data acquired in a biplane detection scheme. These advancements enable direct and quantitative mapping of protein distribution on ruffled plasma membranes with near isotropic 3D nanometer resolution. As demonstrated successfully for CD4 and CD45 receptors, the described workflow is a straightforward quantitative technique to study molecules and their interactions at the complex surface nanomorphology of differentiated metazoan cells.

Sign in / Sign up

Export Citation Format

Share Document