von Willebrand factor (vWF)
von Willebrand Factor (vWF), also known as ristocetin cofactor, is important in the maintenance of hemostasis. It promotes adhesion of platelets to the sites of vascular injury by forming a molecular bridge between sub-endothelial collagen matrix and platelet-surface receptor complex GPIb-IX-V. It also acts as a chaperone for coagulation factor VIII, delivering it to the site of injury, stabilizing its heterodimeric structure and protecting it from premature clearance from plasma. vWF is synthesized in endothelial cells and in megakaryocytes as a number of subunits that polymerize and combine with the factor VIII to form a large complex. In the plasma, vWF exists as a heterogenous population of large polymers to which the coagulant factor VIII is complexed by non-covalent bonds. It is an acute-phase reactant.
Swiss-Prot Accession Number: Q8CIZ8