scholarly journals Regulatory Mechanism of the Interaction between von Willebrand Factor and Platelet Glycoprotein Ib

1992 ◽  
Vol 3 (4) ◽  
pp. 221-230
Author(s):  
Mitsuhiko SUGIMOTO
Keyword(s):  
Von Willebrand Factor ◽  
Regulatory Mechanism ◽  
Platelet Glycoprotein ◽  
Glycoprotein Ib ◽  
Von Willebrand ◽  
Willebrand Factor

Glycoprotein Ib Can Mediate Endothelial Cell Attachment to a von Willebrand Factor Substratum

1995 ◽  
Vol 73 (02) ◽  
pp. 309-317 ◽  
Author(s):  
Dorothy A Beacham ◽  
Miguel A Cruz ◽  
Robert I Handin
Keyword(s):  
Endothelial Cell ◽  
Von Willebrand Factor ◽  
Cell Attachment ◽  
Umbilical Vein ◽  
Single Amino Acid ◽  
Cell Surface Expression ◽  
Platelet Glycoprotein ◽  
Glycoprotein Ib ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryIntroduction of single amino acid substitutions into the C-terminal Arg-Gly-Asp-Ser (RGDS) site of von Willebrand Factor, referred to as RGD mutant vWF, selectively abrogated vWF binding to platelet glycoprotein IIb/IIIa (GpIIb/IIIa, αIIbβ3 and abolished human umbilical vein endothelial cell (HUVEC) spreading, but not attachment, to RGD mutant vWF (Beacham, D. A., Wise, R. J., Turci, S. M. and Handin, R. I. 1992. J. Biol. Chem. 167, 3409-3415). These results suggested that in addition to the vitronectin receptor (VNR, αvβ3), a second endothelial membrane glycoprotein can mediate HUVEC adhesion to vWF. HUVEC attachment to wild-type (WT) and RGD-mutant vWF was reduced by two proteins known to block the vWF-platelet glycoprotein Ib/IX (GpIb/IX) interaction, the monoclonal antibody AS-7 and the recombinant polypeptide, vWF-A1. The addition of cytochalasin B or DNase I to disrupt potential GPIbα-cytoskeletal interactions enhanced the immunoprecipitation of endothelial GPIbα, caused HUVEC to round up, and increased HUVEC adhesion to RGD mutant vWF. These results indicate that while the VNR is the primary adhesion receptor for vWF, endothelial GPIbα can mediate HUVEC attachment to vWF. GpIb-dependent attachment could contribute to HUVEC adhesion under conditions when cell surface expression of the VNR is downregulated, and VNR-dependent adhesion is reduced.

scholarly journals The binding domain of von Willebrand factor to sulfatides is distinct from those interacting with glycoprotein Ib, heparin, and collagen and resides between amino acid residues Leu 512 and Lys 673

Blood ◽  
1991 ◽  
Vol 78 (9) ◽  
pp. 2310-2317 ◽  
Author(s):  
O Christophe ◽  
B Obert ◽  
D Meyer ◽  
JP Girma
Keyword(s):  
Von Willebrand Factor ◽  
Competitive Inhibition ◽  
Binding Domain ◽  
Functional Site ◽  
Platelet Glycoprotein ◽  
Functional Domain ◽  
Amino Acid Residues ◽  
Glycoprotein Ib ◽  
Von Willebrand ◽  
Willebrand Factor

A series of proteolytic fragments of human von Willebrand Factor (vWF) was purified to characterize the functional site that supports its interaction with sulfatides. SpIII, an N-terminal homodimer generated by V-8 protease (amino acids [AA] 1 to 1365), bound to sulfatides in a dose-dependent and saturable way. SpIII also totally inhibited the binding of vWF to sulfatides and SpIII binding was completely abolished by vWF. In contrast, SpII, the complementary C-terminal homodimer (AA 1366 to 2050), did not exhibit any binding affinity for sulfatides. Four purified fragments overlapping the sequence of SpIII were also tested for their ability to interact with sulfatides. An N-terminal monomeric 34-Kd fragment (P34, AA 1 to 272) generated by plasmin, a central monomer (SpI, AA 911 to 1365) produced by digestion with V-8 protease, and a tetrameric fragment III-T2 (comprising a pair of the two sequences AA 273 to 511 and AA 674 to 728) produced by secondary digestion of SpIII with trypsin did not interact with sulfatides. In contrast, a monomeric 39/34-Kd fragment produced by dispase (AA 480 to 718) bound specifically and with a high affinity to sulfatides and totally displaced vWF or SpIII binding. Conversely, binding of the 39/34-Kd species was totally abolished by vWF or SpIII. Thus, a functional site responsible for sulfatide binding was localized between AA 480 and 718 and comparison of the binding properties of the 39/34-Kd and III-T2 fragments indicated that the sequence 512 to 673 is necessary for the binding to sulfatides. Further mapping of this new functional domain of vWF, based on experiments of competitive inhibition of binding by either heparin or monoclonal antibodies directed toward vWF, showed that the site interacting with sulfatides is distinct from those involved in binding to platelet glycoprotein Ib, collagen, or heparin. This finding was confirmed by experiments using synthetic peptides which also indicated that the sequence comprising AA 569 to 584 is part of the sulfatide-binding domain or influences its activity.

Isolation from commercial aurintricarboxylic acid of the most effective polymeric inhibitors of von Willebrand factor interaction with platelet glycoprotein Ib. Comparison with other polyanionic and polyaromatic polymers

Blood ◽  
1991 ◽  
Vol 78 (9) ◽  
pp. 2291-2298 ◽  
Author(s):  
M Weinstein ◽  
E Vosburgh ◽  
M Phillips ◽  
N Turner ◽  
L Chute-Rose ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Von Willebrand Factor ◽  
Platelet Glycoprotein ◽  
Glycoprotein Ib ◽  
Aurintricarboxylic Acid ◽  
Coronary Artery Thrombosis ◽  
Exclusion Chromatography ◽  
Inhibitory Components ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Solutions of commercial aurintricarboxylic acid (ATA) inhibit ristocetin- or shear stress-induced, von Willebrand factor (vWF)- mediated platelet aggregation by interacting with vWF and blocking its attachment to platelet membrane glycoprotein Ib. ATA has also been shown to prevent cyclic platelet clumping in a dog model of coronary artery thrombosis. Because these ATA solutions are actually a heterogeneous mixture of polyanionic, polycarboxylic polyaromatic polymers of molecular weight (Mr) 200 to greater than 6,000, we separated the most effective inhibitory components of commercial ATA using exclusion chromatography. ATA polymers larger than Mr 700 inhibited ristocetin-induced, vWF-mediated platelet aggregation more effectively than smaller ATA polymers, whereas shear-induced, vWF- mediated platelet aggregation was optimally inhibited by ATA polymers of Mr greater than or equal to 2,500. Platelet aggregation mediated by vWF was not inhibited by a nonphenolic, polyanionic polymer (polyglutamic acid) or by a polyphenolic ATA-like polymer (aurin) devoid of carboxyl groups. Polyanionic, polysulfonated aromatic polymers (polystyrene sulfonate) of Mr 35, 17.4, 8, and 4.6 x 10(3) inhibited ristocetin- and shear-induced, vWF-mediated aggregation with less potency on a mass/volume basis than large polymers of ATA. We conclude that a polyanionic, polycarboxylated, polyphenolic ATA polymer of Mr 2,500 is optimally potent as an inhibitor of shear- and ristocetin-induced, vWF-mediated platelet aggregation and is likely to be more effective than solutions of commercial ATA as an anti-arterial thrombotic agent.

Inhibition of the Binding of von Willebrand Factor to the Platelet Glycoprotein Ib-IX with an Inhibitor of 14-3-3 and Glycoprotein Ib-IX Interaction.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1657-1657
Author(s):  
Kesheng Dai ◽  
Richard Bodnar ◽  
Michael Berndt ◽  
Xiaoping Du
Keyword(s):  
Von Willebrand Factor ◽  
Intracellular Signaling ◽  
Platelet Adhesion ◽  
Platelet Glycoprotein ◽  
Glycoprotein Ib ◽  
Prolonged Bleeding Time ◽  
Binding Function ◽  
Platelet Receptor ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Platelet adhesion and activation are essential for thrombosis and hemostasis. In arteries and capillaries where blood flow shear rate is high, initial platelet adhesion is dependent on the binding of von Willebrand factor (VWF) to its platelet receptor, the glycoprotein (GP) Ib-IX-V complex (GPIb-IX), which consists of four subunits, GPIbα, GPIbβ, GPIX and GPV. We have shown previously that a phosphoserine-dependent intracellular signaling molecule, 14-3-3, interacts with the C-terminal SIRYSGHSL610 sequence in the cytoplasmic domain of GPIbα, and this interaction is dependent upon phosphorylation at Serine 609 of GPIbα. Here we show that a short cell-permeable myristoylated phospho-peptide corresponding to the 14-3-3 binding sequence of GPIbα inhibits VWF binding to platelets and VWF-mediated platelet adhesion. This peptide also specifically inhibits VWF-dependent platelet agglutination induced by ristocetin but has no significant effect on platelet aggregation induced by platelet agonists such as ADP and collagen. Furthermore, intravenous injection of this phospho-peptide caused significantly prolonged bleeding time in mice. Thus, 14-3-3 interaction with GPIbα plays critical roles in VWF binding function of GPIb-IX and hemostatic function of platelets. These results also suggest a new type of anti-platelet drugs that may potentially be useful in treating thrombosis.

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