Alterations of wheat-germ agglutinin binding pattern on cell surface of blood platelets after thrombin stimulation

1989 ◽  
Vol 91 (6) ◽  
pp. 461-467 ◽  
Author(s):  
T. Daimon ◽  
I. S. Sano-Martins
Keyword(s):  
Cell Surface ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Blood Platelets ◽  
Binding Pattern

Structural analysis of cell-surface glycopeptides which bind to wheat germ agglutinin

1984 ◽  
Vol 12 (4) ◽  
pp. 655-655
Author(s):  
JOHN T. GALLAGHER ◽  
ANDREW MORRIS ◽  
MIKE DEXTER
Keyword(s):  
Structural Analysis ◽  
Cell Surface ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ

scholarly journals Differential involvement of cell surface sialic acid residues in wheat germ agglutinin binding to parental and wheat germ agglutinin-resistant Chinese hamster ovary cells.

1980 ◽  
Vol 85 (1) ◽  
pp. 60-69 ◽  
Author(s):  
P Stanley ◽  
T Sudo ◽  
J P Carver
Keyword(s):  
Sialic Acid ◽  
Cell Surface ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cho Cell ◽  
Differential Involvement

Two Chinese hamster ovary (CHO) cell mutants selected for resistance to wheat germ agglutinin (WGA) have been shown to exhibit defective sialylation of membrane glycoproteins and a membrane glycolipid, GM3. The mutants (termed WgaRII and WgaRIII) have been previously shown to belong to different genetic complementation groups and to exhibit different WGA-binding abilities. These mutants and a WGA-resistant CHO cell mutant termed WgaRI (which also possesses a surface sialylation defect arising from a deficient N-acetylglucosaminyltransferase activity), have enabled us to investigate the role of sialic acid in WGA binding at the cell surface. Scatchard plots of the binding of 125I-WGA (1 ng/ml to 1 mg/ml) to parental and WgaR CHO cells before and after a brief treatment with neuraminidase provide evidence for several different groups of sialic acid residues at the CHO cell surface which may be distinquished by their differential involvement in WGA binding to CHO cells.

scholarly journals Wheat germ agglutinin blocks the biological effects of nerve growth factor.

1985 ◽  
Vol 101 (5) ◽  
pp. 1690-1694 ◽  
Author(s):  
G E Landreth ◽  
L K Williams ◽  
C McCutchen
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Cell Surface ◽  
Pc12 Cells ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Biological Effects ◽  
Receptor Interaction ◽  
Cytoskeletal Protein ◽  
Ngf Receptor

The binding of nerve growth factor (NGF) to specific cell surface receptors initiates a variety of effects that lead to the morphological and biochemical differentiation of clonal pheochromocytoma, PC12, cells. The lectin wheat germ agglutinin (WGA) alters the characteristics of NGF-receptor interaction. We have found that treatment of PC12 cells with WGA dramatically and reversibly inhibits the ability of NGF to elicit three distinct biological effects characteristic of NGF action. Two of these events, the rapid ruffling of cell-surface membranes and the stimulation of the phosphorylation of a 250-kD cytoskeletal protein in situ, occur rapidly and are an immediate consequence of receptor occupancy. Both of these effects are blocked by pretreatment of the cells with WGA. WGA was also found to inhibit the NGF-stimulated regeneration of neurites that occurs over 1-2 d. Both the WGA inhibition of neurite outgrowth and the phosphorylation of the 250-kD cytoskeletal protein were reversed upon addition of the specific sugar N-acetylglucosamine. These data demonstrate that the WGA-induced changes in the NGF-receptor interaction reflect important alterations in the ability of the receptor to transmit biological signals, resulting in the abrogation of the biological effects of NGF on these cells.

Intracellular trafficking of metallocarboxypeptidase D in AtT-20 cells: localization to the trans-Golgi network and recycling from the cell surface

1998 ◽  
Vol 111 (7) ◽  
pp. 877-885 ◽  
Author(s):  
O. Varlamov ◽  
L.D. Fricker
Keyword(s):  
Cell Surface ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Secretory Pathway ◽  
Brefeldin A ◽  
Full Length ◽  
Recycling Endosomes ◽  
Trans Golgi Network ◽  
Cell Processes ◽  
Golgi Network

Carboxypeptidase D (CPD) is a recently discovered membrane-bound metallocarboxypeptidase that has been proposed to be involved in the post-translational processing of peptides and proteins that transit the secretory pathway. In the present study, the intracellular distribution of CPD was examined in AtT-20 cells, a mouse anterior pituitary-derived corticotroph. Antisera to CPD stain the same intracellular structures as those labeled with furin and wheat germ agglutinin. This distribution is distinct from carboxypeptidase E, which is localized to the secretory vesicles in the cell processes. The perinuclear distribution of CPD is detected even when the AtT-20 cells are treated with brefeldin A for 1–30 minutes, suggesting that CPD is present in the trans-Golgi network (TGN). Although CPD is predominantly found in the TGN, an antiserum to the full length protein is internalized within 15–30 minutes of incubation at 37 degrees C. In contrast, an antiserum raised against the C-terminal region of CPD does not become internalized, suggesting that this domain is cytosolic. The antiserum to the full length CPD is internalized to a structure that co-stains with furin and wheat germ agglutinin, but is distinct from transferrin recycling endosomes. The internalization of CPD is not substantially affected by treatment of the AtT-20 cells with brefeldin A. These data are consistent with the cycling of CPD to the cell surface and back to the TGN. The TGN localization of CPD raises the possibility of a role for this enzyme in the processing of proteins that transit the secretory pathway.

scholarly journals Wheat-germ-agglutinin and Ricinus communis-agglutinin-binding sites of BHK cells compared with each other and with 140 kDa fibronectin receptors

1988 ◽  
Vol 251 (1) ◽  
pp. 269-277 ◽  
Author(s):  
T L Tuan ◽  
F Grinnell
Keyword(s):  
Cell Surface ◽  
Binding Sites ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Ricinus Communis ◽  
Chinese Hamster ◽  
Surface Binding ◽  
Bhk Cells ◽  
Receptor Complexes ◽  
Ricinus Communis Agglutinin

We compared the wheat-germ agglutinin (WGA) and Ricinus communis agglutinin (RCA) binding sites of baby-hamster kidney (BHK) cells. There were 1.01 × 10(8) WGA-binding sites per cell (Kd = 0.027 nM) and 6 × 10(6) RCA-binding sites per cell (Kd = 0.014 nM). Binding of WGA or RCA to BHK cells resulted in more than 75% of the cell-surface binding sites becoming associated with the cytoskeleton (i.e. resistant to extraction with detergent), although no more than 10% of these sites were associated with the cytoskeleton before addition of the lectins. After binding of WGA to the cells, the cell surface was cross-linked so extensively that it remained intact even after detergent extraction of the treated cells, and could be observed by electron microscopy. A similar cross-linking effect did not occur after binding of RCA to cells, which may be because there were so many more binding sites for WGA than for RCA. The composition of WGA- and RCA-binding molecules was analysed by lectin affinity chromatography of metabolically radiolabelled BHK cells. We found that in the WGA-binding-molecule preparations there were eight major polypeptides, ranging in molecular mass from 93 to 340 kDa, and that the RCA-binding molecules were a subpopulation of the WGA-binding molecules. A polyclonal antibody against the 140 kDa fibronectin (FN) receptors of Chinese-hamster ovary (CHO) cells immunoblotted a 145 kDa polypeptide component in both WGA- and RCA-binding-molecule preparations. The results indicated that the 145 kDa component was present in at least two FN-receptor complexes that differed in glycosylation, only one of which was able to bind to RCA affinity columns. The oligomeric nature of the FN-receptor complex, which contained three polypeptides with molecular masses of 120-145 kDa, was demonstrated by using anti-(CHO-cell FN receptor) antibodies to immunoprecipitate extracts prepared from radioiodinated BHK cells.

scholarly journals Identification of asparagine-linked oligosaccharides involved in tumor cell adhesion to laminin and type IV collagen.

1984 ◽  
Vol 99 (4) ◽  
pp. 1416-1423 ◽  
Author(s):  
J W Dennis ◽  
C A Waller ◽  
V Schirrmacher
Keyword(s):  
Cell Surface ◽  
Tumor Cell ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Matrix Protein ◽  
Type Iv Collagen ◽  
Cell Attachment ◽  
Adhesion Assay ◽  
Type Iv ◽  
Tumor Cell Attachment

MDW4, a wheat germ agglutinin-resistant nonmetastatic mutant of the highly metastatic murine tumor cell line called MDAY-D2 has previously been shown to attach to fibronectin and type IV collagen, whereas MDAY-D2 and phenotypic revertants of MDW4 attached poorly to these substrates. The increased adhesiveness of the mutant cells appeared to be closely related to a lesion in cell surface carbohydrate structures. In an effort to identify the carbohydrates involved in cell attachment, glycopeptides isolated from mutant and wild-type cells as well as from purified glycoproteins were tested for their ability to inhibit the attachment of MDW4 cells to plastic surfaces coated with fibronectin, laminin, or type IV collagen. The addition of mannose-terminating glycopeptide to the adhesion assay inhibited MDW4 cell attachment to type IV collagen. In contrast, a sialylated poly N-acetyllactosamine-containing glycopeptide, isolated from wheat germ agglutinin-sensitive MDAY-D2 cells but absent in MDW4 cells, inhibited MDW4 attachment to laminin. None of the glycopeptides used in this study inhibited attachment of MDW4 cells to fibronectin-coated plastic. Peptide N-glycosidase treatment of the cells to remove surface asparagine-linked oligosaccharides inhibited MDW4 adhesion to type IV collagen, but not to laminin, and the same treatment of the wheat germ agglutinin-sensitive cells enhanced attachment to laminin. Tumor cell attachment to, and detachment from, the sublaminal matrix protein laminin and type IV collagen are thought to be important events in the metastatic process. Our results indicate that tumor cell attachment to these proteins may be partially modulated by the expression of specific oligosaccharide structures associated with the cell surface.

scholarly journals The role of sialic acid in the activation of platelets by wheat germ agglutinin

Blood ◽  
1984 ◽  
Vol 63 (1) ◽  
pp. 181-187
Author(s):  
P Ganguly ◽  
NG Fossett
Keyword(s):  
Sialic Acid ◽  
Dissociation Constant ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Blood Platelets ◽  
Critical Role ◽  
Human Platelets ◽  
Apparent Dissociation Constant ◽  
Serotonin Secretion

Sialic acid is believed to play a critical role in the survival of blood platelets in circulation. Wheat germ agglutinin, which shows specificity for sialic acid, N-acetylglucosamine, and N- acetylgalactosamine, strongly activates platelets. The role of sialic acid in platelet activation by this lectin was studied utilizing neuraminidase-treated platelets and the succinylated lectin that has been reported not to recognize sialic acid. The succinylated lectin had a dimeric structure similar to the native lectin, but migrated more slowly in gel electrophoresis. The modified lectin bound to about 2.8 X 10(5) sites/cell, with an apparent dissociation constant of 2 microM compared to 5 X 10(5) sites/cell and a dissociation constant of 0.4 microM for the native lectin. The succinylated lectin neither aggregated nor agglutinated platelets, but agglutination of red cells in microtiter plates was normal. Aggregation of platelets by either wheat germ agglutinin or ristocetin was not affected by the succinylated lectin. Since the native wheat germ agglutinin is a strong activator of platelets and the succinylated derivative was devoid of all activity, it appears that a sialoprotein acts as the biologic receptor of wheat germ agglutinin in human platelets. This suggestion was strengthened by the observation that platelets treated with different concentrations of neuraminidase had a decreased capacity to bind this lectin. These platelets also showed reduced aggregation and serotonin secretion when activated with the native lectin. Since sialic acid has been implicated in the removal of platelets from circulation, wheat germ agglutinin may prove to be a useful tool to explore those clinical conditions in which platelet survival is shortened.

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