Factor VIII C-domains are believed to have specific functions in cofactor activity and in interactions with von Willebrand factor. We have previously shown that factor VIII is co-targeted with von Willebrand factor to the Weibel-Palade bodies in blood outgrowth endothelial cells, even when factor VIII carries mutations in the light chain that are associated with defective von Willebrand factor binding. In this study, we addressed the contribution of individual factor VIII C-domains in intracellular targeting, von Willebrand factor binding and cofactor activity by factor VIII/V C-domain swapping. Blood outgrowth endothelial cells were transduced with lentivirus encoding factor V, factor VIII or YFP-tagged C-domain chimeras, and examined by confocal microscopy. The same chimeras were produced in HEK293-cells for characterization and chemical foot-printing by mass spectrometry. In contrast to factor VIII, factor V did not target to Weibel-Palade bodies. The chimeras showed reduced Weibel-Palade body targeting, suggesting that this requires the factor VIII C1-C2 region. The factor VIII/V-C1 chimera did not bind von Willebrand factor and had reduced affinity for activated factor IX, whereas the factor VIII/V-C2 chimera showed a minor reduction in von Willebrand factor binding and normal interaction with activated factor IX. This suggests that mainly the C1-domain carries factor VIII-specific features in assembly with von Willebrand factor and activated factor IX. Foot-printing analysis of the chimeras revealed increased exposure of lysine residues in the A1/C2- and C1/C2-domain interface, suggesting increased C2-domain mobility and disruption of the natural C-domain tandem pair orientation. Apparently, this affects intracellular trafficking, but not extracellular function.
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http://dx.doi.org/10.3324/haematol.2016.153163 | DOI Listing |
Best Pract Res Clin Gastroenterol
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Aster Integrated Liver Care, Aster Medcity, Kochi, India.
Acute liver failure (ALF) is a rare and dynamic syndrome occurring as a sequela of severe acute liver injury (ALI). Its mortality ranges from 50% to 75% based on the aetiology, patients age and severity of encephalopathy at admission. With improvement in intensive care techniques, transplant-free survival in ALF has improved over time.
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Discovery Research, Scientific Innovation Office, Grifols, Palou 3, 08150, Parets del Vallès, Barcelona, Spain.
Hemophilia A (HA) patients under emicizumab prophylaxis may require the concomitant use of procoagulant factors for breakthrough bleedings or immune tolerance induction (ITI). The aim of this study is to evaluate the ex vivo procoagulant effect of plasma-derived FVIII concentrates containing von Willebrand factor (pdFVIII/VWF) in samples from patients with severe HA without inhibitors on emicizumab prophylaxis. Samples from healthy controls (HC) and HA patients were drawn in sodium citrate plus corn trypsin inhibitor tubes and spiked with increasing concentrations of pdFVIII/VWF concentrates (10-400 IU/dL) (Fanhdi/Alphanate, Grifols), activated prothrombin complex concentrate (aPCC, 0.
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National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, School of Life Sciences, College of Agriculture, Henan University, Kaifeng 475004, China. Electronic address:
Amino acid/auxin permeases (AAAPs) play crucial roles in plant development and response to environmental stimuli. They have been characterized at genome-wide levels in several plant species. However, little is known about the AAAP genes in Gossypium.
View Article and Find Full Text PDFDrugs R D
December 2024
Center for Thrombosis and Hemorrhagic Diseases, IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy.
Haemophilia
December 2024
Institute of Experimental Hematology and Transfusion Medicine, Medical Faculty, University Hospital Bonn, University of Bonn, Bonn, Germany.
Introduction: Maintaining the balance between procoagulant and anticoagulant factors is essential for effective haemostasis. Emerging evidence suggests a modulation of bleeding tendency by factors in the anticoagulant and fibrinolytic systems.
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