Simultaneous Exposure of Sites in von Willebrand Factor for Glycoprotein Ib Binding and ADAMTS13 Cleavage

Chen, Junmei; Ling, Minhua; Fu, Xiaoyun; López, José A.; Chung, Dominic W.

doi:10.1161/atvbaha.112.254144

Cited by 25 publications

(20 citation statements)

References 27 publications

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“…Additionally, the interaction between platelet vimentin and the gain-of-function A1(R1450E) A2A3 mutant, which binds to vimentin (this study) and GPIba in a ristocetin-independent manner, 9,18 was efficiently reduced by the anti-vimentin antibody. These outcomes are consistent with the information that VWF exposes the cleavage site for ADAMTS-13 in the A2 domain on a conformational change induced by ristocetin, 35 indicating that vimentin interacts specifically with the active form of VWF.…”

Section: Discussionsupporting

confidence: 88%

Platelet adhesion involves a novel interaction between vimentin and von Willebrand factor under high shear stress

Behymer

Correa

et al. 2014

Blood

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• Vimentin expressed on the platelet surface serves as adhesive receptor for VWF.The interaction between platelet receptor glycoprotein Iba and the A1 domain of von Willebrand factor (VWF) mediates tethering/translocation of platelets to sites of vascular injury. Unexpectedly, we observed platelets translocating over A1A2A3 domains protein slower than on A1 domain at high shear stress. This observation suggests an additional interaction between A domains and an adhesive receptor. We investigated vimentin because we have data showing the interaction of vimentin with the A2 domain of VWF. Moreover, vimentin is expressed on the platelet surface. This novel interaction was analyzed by using purified VWF, recombinant proteins, anti-vimentin antibodies, parallel flow chamber adhesion assays, flow cytometry, and vimentin-deficient murine platelets. The active form of VWF bound to vimentin, and the purified A2 domain blocked that binding. The interaction of a gain-of-function A1A2A3 mutant with platelet was reduced using anti-vimentin antibody. Platelet adhesion to wild-type (WT) A1A2A3 protein, collagen, and fibrin(ogen) was inhibited (32-75%) by anti-vimentin antibody under high shear stress. Compared with WT mice, platelets from vimentin-deficient mice had a reduced flow-dependent adhesion to both collagen and purified murine VWF. Last, the vimentin knockout mice had a prolonged tail bleeding time. The results describe that platelet vimentin engages VWF during platelet adhesion under high shear stress. (Blood. 2014;123(17):2715-2721 Introduction Atherothrombotic events, including acute coronary syndrome and stroke, are the result of platelet adhesion and activation on the ruptured atherosclerotic plaques. This platelet-mediated arterial thrombosis starts with the contact of the rapidly flowing platelets to components of the damaged blood vessel. von Willebrand factor (VWF), a multimeric plasma and subendothelial glycoprotein, is relevant in mediating platelet adhesion and activation at sites of lesions in the coronary arteries, where high shear conditions prevail.1,2 VWF captures the circulating platelets through its interaction with the platelet receptor glycoprotein (GP)Ib/IX/V complex. This interaction is responsible for the tethering, rolling, and activation of platelets that eventually become firmly adhered, leading to thrombus formation within a coronary artery. 3,4 Mature VWF consists of a 2050-residue subunit formed by domains arranged in the order of D9-D3-A1-A2-A3-D4-B-C. 5 The A1 domain contains the binding site for the platelet receptor GPIba 6 ; the cleavage site for the enzyme ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs)-13 is localized in the A2 domain, 7 and the A3 domain binds to collagen. 8 Unlike the A3 domain, both the A1 and A2 domains do not have access to their ligands until their domain structure is altered.9 This structural modification can be induced by mutations, 10 hydrodynamic forces, 11 immobilization on a surface, or artificially with the modulator ristocetin....

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Section: Discussionsupporting

confidence: 88%

Platelet adhesion involves a novel interaction between vimentin and von Willebrand factor under high shear stress

Behymer

Correa

et al. 2014

Blood

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“…This notion is supported by the report by Hulstein et al [27] that a nanobody made against the VWF A1 detected a very small amount of VWF in blood samples from healthy subjects, but a significantly increased amount of VWF in patients with TTP. It is also supported by our finding that the VWF-fH interaction was enhanced in the presence of ristocetin, which is known to induce an active conformation of VWF [21,28]; and is consistent with a recent report by Turner et al, who showed binding of fH to ULVWF strings secreted by, and anchored to, endothelial cells [29]. Second, VWF exists in the blood as multimers of different sizes and a calculated binding affinity for such a heterogeneous ligand may be accurate only for VWF of a particular size.…”

Section: Discussionsupporting

confidence: 76%

The Interaction between Factor H and Von Willebrand Factor

et al. 2013

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Complement factor H (fH) is a plasma protein that regulates activation of the alternative pathway, and mutations in fH are associated with a rare form of thrombotic microangiopathy (TMA), known as atypical hemolytic uremic syndrome (aHUS). A more common TMA is thrombotic thrombocytopenic purpura, which is caused by the lack of normal ADAMTS-13-mediated cleavage of von Willebrand factor (VWF). We investigated whether fH interacts with VWF and affects cleavage of VWF. We found that factor H binds to VWF in plasma, to plasma-purified VWF, and to recombinant A1 and A2 domains of VWF as detected by co-immunoprecipitation (co-IP) and surface plasmon resonance assays. Factor H enhanced ADAMTS-13-mediated cleavage of recombinant VWF-A2 as determined by quantifying the cleavage products using Western-blotting, enhanced cleavage of a commercially available fragment of VWF-A2 (FRETS-VWF73) as determined by fluorometric assay, and enhanced cleavage of ultralarge (UL) VWF under flow conditions as determined by cleavage of VWF-platelet strings attached to histamine stimulated endothelial cells. Using recombinant full-length and truncated fH molecules, we found that the presence of the C-terminal half of fH molecule is important for binding to VWF-A2 and for enhancing cleavage of the A2 domain by ADAMTS-13. We conclude that factor H binds to VWF and may modulate cleavage of VWF by ADAMTS-13.

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“…The stretching force ensures, however, that the VWF is activated for platelet binding predominantly before deactivation through cleavage. In this respect, the interactions between A1 and A2 may also serve to clarify the role of ristocetin, coupling platelet binding and ADAMTS13 cleavage (48).…”

Section: Main Orientational Modes Of the Autoinhibited Statementioning

confidence: 99%

Force-Sensitive Autoinhibition of the von Willebrand Factor Is Mediated by Interdomain Interactions

Aponte-Santamaría

Huck

Posch

et al. 2015

Biophysical Journal

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Von Willebrand factor (VWF) plays a central role in hemostasis. Triggered by shear-stress, it adheres to platelets at sites of vascular injury. Inactivation of VWF has been associated to the shielding of its adhesion sites and proteolytic cleavage. However, the molecular nature of this shielding and its coupling to cleavage under shear-forces in flowing blood remain unknown. In this study, we describe, to our knowledge, a new force-sensory mechanism for VWF-platelet binding, which addresses these questions, based on a combination of molecular dynamics (MD) simulations, atomic force microscopy (AFM), and microfluidic experiments. Our MD simulations demonstrate that the VWF A2 domain targets a specific region at the VWF A1 domain, corresponding to the binding site of the platelet glycoprotein Ibα (GPIbα) receptor, thereby causing its blockage. This implies autoinhibition of the VWF for the binding of platelets mediated by the A1-A2 protein-protein interaction. During force-probe MD simulations, a stretching force dissociated the A1A2 complex, thereby unblocking the GPIbα binding site. Dissociation was found to be coupled to the unfolding of the A2 domain, with dissociation predominantly occurring before exposure of the cleavage site in A2, an observation that is supported by our AFM experiments. This suggests that the A2 domain prevents platelet binding in a force-dependent manner, ensuring that VWF initiates hemostasis before inactivation by proteolytic cleavage. Microfluidic experiments with an A2-deletion VWF mutant resulted in increased platelet binding, corroborating the key autoinhibitory role of the A2 domain within VWF multimers. Overall, autoinhibition of VWF mediated by force-dependent interdomain interactions offers the molecular basis for the shear-sensitive growth of VWF-platelet aggregates, and might be similarly involved in shear-induced VWF self-aggregation and other force-sensing functions in hemostasis.

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Simultaneous Exposure of Sites in von Willebrand Factor for Glycoprotein Ib Binding and ADAMTS13 Cleavage

Cited by 25 publications

References 27 publications

Platelet adhesion involves a novel interaction between vimentin and von Willebrand factor under high shear stress

Platelet adhesion involves a novel interaction between vimentin and von Willebrand factor under high shear stress

The Interaction between Factor H and Von Willebrand Factor

Force-Sensitive Autoinhibition of the von Willebrand Factor Is Mediated by Interdomain Interactions

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