scholarly journals The Cytoplasmic Domain of the -Subunit of Glycoprotein (GP) Ib Mediates Attachment of the Entire GP Ib-IX Complex to the Cytoskeleton and Regulates von Willebrand Factor-induced Changes in Cell Morphology

1996 ◽  
Vol 271 (19) ◽  
pp. 11581-11587 ◽  
Author(s):  
Janet G. Cunningham ◽  
Sylvie C. Meyer ◽  
Joan E. B. Fox
Keyword(s):  
Von Willebrand Factor ◽  
Cell Morphology ◽  
Cytoplasmic Domain ◽  
Induced Changes ◽  
Von Willebrand ◽  
Willebrand Factor

The Interaction of Von Willebrand Factor with GPIb-IX Initiates Platelet Apoptosis.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3002-3002
Author(s):  
Suping Li ◽  
Zhicheng Wang ◽  
Yi Liao ◽  
Guanglei Liu ◽  
Weilin Zhang ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Intracellular Signaling ◽  
Conflicts Of Interest ◽  
Cytoplasmic Domain ◽  
Shear Stresses ◽  
Apoptotic Signaling ◽  
Platelet Apoptosis ◽  
Signaling Events ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Abstract 3002 Poster Board II-979 Background: The interaction of glycoprotein (GP) Ibalpha with von Willebrand factor (VWF) initiates the adherence of platelets to sites of vascular injury, simultaneously triggers intracellular signaling events such as elevation of cytoplasmic calcium and activations of multiple protein kinase pathways which result in the activation of the ligand binding function of GPIIb/IIIa, leading to platelet activation and thrombus formation. The intracellular signaling protein 14-3-3ζ and the membrane skeleton protein filamin A have been confirmed to interact with the intracellular domain of GPIbalpha and play important roles in the regulation of platelet function. The signaling events elicited by GPIbalpha-VWF interaction, such as calcium mobilization and phosphatidylserine (PS) exposure are similar to those occurring during apoptosis. Particularly, the 14-3-3ζ binding domain of GPIbalpha has been reported to involve in the regulation of cell proliferations. However, it is still unclear whether the GPIbalpha-VWF interaction induces platelet apoptosis. Objectives: To investigate whether the GPIbalpha-VWF interaction induces platelet apoptosis and the role of 14-3-3ζ in apoptotic signaling. Methods: Apoptotic events were assessed in platelets or Chinese hamster ovary (CHO) cells expressing GPIb-IX (1b9) interacted with VWF by flow cytometry or Western blotting. Results: Ristocetin induced GPIbalpha-VWF interaction elicited apoptotic events in platelets, including phosphatidylserine exposure, elevations of Bax and Bak, gelsolin cleavage, and depolarization of mitochondrial inner transmembrane potential. Apoptotic events were also elicited in platelets exposed to pathologic shear stresses in the presence of VWF, however, the shear-induced apoptosis was eliminated by anti-GPIbalpha antibody AK-2. Furthermore, apoptotic events occurred in 1b9 cells stimulated with VWF and ristocetin, but were significantly diminished in two CHO cell lines expressing mutant GPIb-IX with truncation of the cytoplasmic domain of GPIbalpha or a serine-to-alanine mutation at 14-3-3ζ binding site in GPIbalpha. Conclusions: This study demonstrates that the GPIbalpha-VWF interaction induces apoptotic events in platelets and association of 14-3-3ζ with the cytoplasmic domain of GPIbalpha is essential for apoptotic signaling. The finding may suggest a novel mechanism for platelet clearance or some thrombocytopenic diseases. The reagents that block 14-3-3ζ-GPIbalpha interaction might be potentially useful in platelet storage or anti-thrombocytopenia. Disclosures: No relevant conflicts of interest to declare.

Filamin A binding to the cytoplasmic tail of glycoprotein Ibα regulates von Willebrand factor–induced platelet activation

Blood ◽  
2003 ◽  
Vol 102 (6) ◽  
pp. 2122-2129 ◽  
Author(s):  
Shuju Feng ◽  
Julio C. Reséndiz ◽  
Xin Lu ◽  
Michael H. Kroll
Keyword(s):  
Shear Stress ◽  
Platelet Aggregation ◽  
Fusion Protein ◽  
Platelet Activation ◽  
Von Willebrand Factor ◽  
Cytoplasmic Tail ◽  
Cytoplasmic Domain ◽  
Filamin A ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract We examined the hypothesis that filamin A binding to the cytoplasmic tail of platelet glycoprotein Ibα (GpIbα) is regulated by pathologic shear stress and modulates von Willebrand factor (VWF)–induced platelet activation. To begin, we examined filamin binding to GpIbα in Chinese hamster ovary cells coexpressing mutant human GpIb-IX and wild-type human filamin A. We observed that many different deletions and truncations N-terminal to GpIbα's cytoplasmic domain residue 594 disrupted filamin A binding, but that binding was unaffected by 14 different point mutations in hydrophilic residues between amino acids 557 and 593. To try to narrow GpIbα's filamin A–binding domain, we next measured the effect of several cytoplasmic domain peptides on human filamin A binding to a GST-GpIbα cytoplasmic domain fusion protein. One peptide (residues 557-575; designated “A4 peptide”) inhibited filamin A binding to the GST-GpIbα cytoplasmic domain fusion protein and competed with GpIbα for binding to filamin A. When the A4 peptide was delivered to intact human platelets using a carrier peptide, we observed the dose-dependent inhibition of VWF-induced platelet aggregation in response to both ristocetin and shear stress. The effect of the A4 peptide on shear-induced platelet aggregation was accompanied by the attenuation of shear-induced filamin A binding to GpIbα and diminished shear-dependent protein tyrosine phosphorylation. These results suggest that shear-dependent VWF-induced platelet activation affects filamin A binding to GpIb-IX-V, and that filamin A binding to the cytoplasmic tail of GpIbα regulates proaggregatory tyrosine kinase signaling.

The Cytoplasmic Domain of Glycoprotein (GP) Ibα Constrains the Lateral Diffusion of the GP Ib−IX Complex and Modulates von Willebrand Factor Binding†

Biochemistry ◽  
1997 ◽  
Vol 36 (41) ◽  
pp. 12421-12427 ◽  
Author(s):  
Jing-Fei Dong ◽  
Chester Q. Li ◽  
Garunee Sae-Tung ◽  
William Hyun ◽  
Vahid Afshar-Kharghan ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Lateral Diffusion ◽  
Cytoplasmic Domain ◽  
Factor Binding ◽  
Von Willebrand ◽  
Willebrand Factor

The Association of 14-3-3ζ and Filamin A with the Central Cytoplasmic Domain of GPIbα Involves in Regulation of the Von Willebrand Factor Binding and Signaling Functions of Platelet Glycoprotein Ib-IX.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 5073-5073
Author(s):  
Weilin Zhang ◽  
Yanhong Yuan ◽  
Lili Zhao ◽  
Yi Liao ◽  
Changgeng Ruan ◽  
...  
Keyword(s):  
Binding Site ◽  
Von Willebrand Factor ◽  
Intracellular Signaling ◽  
Cytoplasmic Domain ◽  
Platelet Glycoprotein ◽  
Filamin A ◽  
Glycoprotein Ib ◽  
Binding Function ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Abstract 5073 Introduction Conformational changes in von Willebrand factor (VWF) exposed at the injured vessel wall initiate platelet tethering and simultaneously trigger signaling cascades leading to platelet adhesion, spreading, and thrombus formation. Although the intracellular signaling protein 14-3-3ζ and the membrane skeleton protein filamin A have been confirmed to interact with the cytoplasmic domain of GPIbα and involve in the regulation of VWF binding function, whereas, the mechanisms still remain unclear. We have recently identified a novel 14-3-3ζ binding site with partial phosphorylation of Ser559 in resting platelets located in the cytoplasmic filamin A binding domain of GPIbα. Disruption of the central cytoplasmic 14-3-3ζ binding site of GPIbα did not abolish the interaction between 14-3-3ζ and GPIb-IX, whereas obviously diminished VWF binding function. Here we show that disruption of 14-3-3ζ binding to GPIbα by GPIbα mutants or cell permeable peptides enhances the association of filamin A with GPIb-IX and the expression of GPIb-IX in the plasma membrane. In contrast, disruption of 14-3-3ζ binding to GPIbβ, which would enhance the opportunity for 14-3-3ζ monomer to bind to GPIbα, reduces filamin A-GPIb-IX interaction and GPIb-IX membrane expression. Compared with a GPIb-IX mutant truncating the whole cytoplasmic domain of GPIbα (Δ551), GPIb-IX mutant retaining only the central 14-3-3ζ binding site of the cytoplasmic domain of GPIbα (Δ565) showed an enhanced cell adhesion to VWF under flow and ristocetin-induced VWF binding. Furthermore, the two cell permeable peptides, MP-P and MPαC, which had been confirmed to block the central 14-3-3ζ binding site of GPIbα (MP-P) or diminished the association of 14-3-3ζ with GPIb-IX complex (MPαC), obviously inhibited ristocetin induced wild-type GPIb-IX cell aggregation. In addition, MP-P and MPαC inhibited botrocetin-induced platelet spreading and lamellipodia formation on VWF matrix, and GPIb-IX-VWF interaction induced co-immunoprecipitation of Src with GPIb-IX. Taken together, these data indicate that the binding of 14-3-3ζ and filamin A to the central cytoplasmic domain of GPIbα involves in regulation of surface expression, VWF binding and signaling functions of glycoprotein Ib-IX. Disclosures No relevant conflicts of interest to declare.

The role of glycoprotein Ibalpha and von Willebrand factor interaction in stroke development

2010 ◽  
Vol 30 (03) ◽  
pp. 136-138 ◽  
Author(s):  
C. Kleinschnitz ◽  
B. Nieswandt ◽  
G. Stoll
Keyword(s):  
Ischemic Stroke ◽  
Von Willebrand Factor ◽  
Treatment Options ◽  
Serum Levels ◽  
Artery Occlusion ◽  
Downstream Signaling ◽  
Phospholipase D1 ◽  
Induced Changes ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryIschaemic stroke is a devastating disease with limited treatment options due to numerous uncertainties regarding the underlying pathophysiology. The contribution of glycoprotein (GP)Ibα and von Willebrand factor (VWF) in stroke development has only recently been established in mice. Complete blockade of GPIbα led to a significant reduction of infarct volumes in mice undergoing one hour of transient middle cerebral artery occlusion (tMCAO). High shear-induced changes in VWF confirmation are a prerequisite for VWF binding to collagen and GPIbα expressed on platelets. Importantly, transgenic VWF−/−mice were similarly protected against ischemic stroke after tMCAO, and hydrodynamic injection of a VWF-encoding plasmid restored VWF serum levels and the susceptibility towards stroke. Secreted VWF is rapidly cleaved by ADAMTS13. Accordingly, ADAMTS13 deficient mice developed larger infarction after tMCAO, while infusion of recombinant ADAMTS13 into wild-type mice was strokeprotective. In conclusion, there is compelling evidence that GPIbα/VWF interactions and downstream signaling via phospholipase D1 (PLD1) provide new therapeutic targets in ischemic stroke.

scholarly journals DDAVP and epinephrine-induced changes in the localization of von Willebrand factor antigen in endothelial cells of human oral mucosa

Blood ◽  
1988 ◽  
Vol 72 (3) ◽  
pp. 850-854 ◽  
Author(s):  
M Takeuchi ◽  
H Nagura ◽  
T Kaneda
Keyword(s):  
Endothelial Cells ◽  
Oral Mucosa ◽  
Von Willebrand Factor ◽  
Antibody Technique ◽  
Von Willebrand Factor Antigen ◽  
Capillary Endothelial Cells ◽  
Induced Changes ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen

Abstract A peroxidase-labeled antibody technique revealed von Willebrand factor antigen (vWF:Ag) in rough endoplasmic reticulum (rER), the perinuclear region, and the cytoplasmic vesicles of capillary endothelial cells in oral mucosa. After administration of epinephrine or 1-deamino-8-D- arginine vasopressin (DDAVP), the localization of vWF:Ag was shown to have changed to the basement membrane and the surrounding interstitium. This change of vWF:Ag localization induced by epinephrine and DDAVP may play a role in the adhesion of platelets to subendothelium following endothelial injury during surgery and may be an unknown hemostatic effect of these drugs.

scholarly journals DDAVP and epinephrine-induced changes in the localization of von Willebrand factor antigen in endothelial cells of human oral mucosa

Blood ◽  
1988 ◽  
Vol 72 (3) ◽  
pp. 850-854 ◽  
Author(s):  
M Takeuchi ◽  
H Nagura ◽  
T Kaneda
Keyword(s):  
Endothelial Cells ◽  
Oral Mucosa ◽  
Von Willebrand Factor ◽  
Antibody Technique ◽  
Von Willebrand Factor Antigen ◽  
Capillary Endothelial Cells ◽  
Induced Changes ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen

A peroxidase-labeled antibody technique revealed von Willebrand factor antigen (vWF:Ag) in rough endoplasmic reticulum (rER), the perinuclear region, and the cytoplasmic vesicles of capillary endothelial cells in oral mucosa. After administration of epinephrine or 1-deamino-8-D- arginine vasopressin (DDAVP), the localization of vWF:Ag was shown to have changed to the basement membrane and the surrounding interstitium. This change of vWF:Ag localization induced by epinephrine and DDAVP may play a role in the adhesion of platelets to subendothelium following endothelial injury during surgery and may be an unknown hemostatic effect of these drugs.

Role of the Glycoprotein (GP)IbαaIb Cytoplasmic Domain in Regulating the Von Willebrand Factor-Binding Functions of the Platelet GPIb-IX-V Complex.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. SCI-39-SCI-39
Author(s):  
José A. López ◽  
Adam Munday
Keyword(s):  
Shear Stress ◽  
Protein Kinase ◽  
Von Willebrand Factor ◽  
Adaptor Protein ◽  
Cytoplasmic Tail ◽  
Cytoplasmic Domain ◽  
Arterial System ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Abstract SCI-39 The platelet glycoprotein (GP) Ib-IX-V complex mediates the initial attachment of platelets to regions of blood vessel damage by binding von Willebrand factor (VWF) exposed in the matrix at the site of injury. This interaction is especially important in the arterial system and microvasculature, given that it is the preferred platelet adhesive event at high shear stress. The interaction is positively and negatively regulated in several ways, including through exposure of the GPIb-binding site on VWF by shear stress or collagen binding, cleavage of VWF by the metalloprotease ADAMTS13, and in the platelet by the targeting of the GPIb-IX-V complex to lipid rafts, cytoskeletal attachments, and binding of the adaptor protein 14-3-3. Association with 14-3-3 has complex roles in regulating accessibility of GPIbα (the ligand-binding subunit of the complex), as several binding sites have been identified within the cytoplasmic domains for this adaptor molecule, and these are regulated by phosphorylation. To address the role of GPIbα phosphorylation in regulating platelet adhesion to VWF, we mutated 5 cytoplasmic Ser and Thr residues that were predicted by bioinformatics programs to be targets for serine/threonine kinases (Thr547, Ser566, Ser587, Ser590, Ser609) and expressed the mutants either as an isolated cytoplasmic domain or in intact GP Ibα as part of a GP Ib-IX complex expressed in CHO cells. We tested whether the following kinases could phosphorylate a recombinant GP Iba cytoplasmic tail: protein kinase A (PKA), protein kinase C (PKC), calmodulin-dependent kinase II (CaMKII) and Akt. All but Akt phosphorylated the region. We then tested polypeptides with various combinations of mutations to these residues for phosphorylation by PKA, and found that this kinase phosphorylated each of the residues except Ser590. We also examined the effect of the mutations on 14-3-3z association and on cell attachment and rolling on VWF. The findings from these studies were complex, with the results of 14-3-3 association suggesting a hierarchy of 14-3-3 binding. This binding did not correlate with the effect of the mutations on attachment on VWF or the rolling velocity profiles. Nevertheless, mutants could be clustered in terms of these effects, the aggregate of the data suggesting a very complex pattern of GPIb-IX-V regulation by the GP Ibα cytoplasmic tail, which will have to be taken into account when considering the association of GP Ibα with 14-3-3 as an antithrombotic target. Disclosures No relevant conflicts of interest to declare.

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