Von Willebrand factor A1 domain (VWF-A1)

The von Willebrand factor A1 domain (VWF-A1) is a key functional domain (~185 amino acid loop) within the large plasma glycoprotein von Willebrand factor, essential for mediating platelet adhesion under the high shear conditions of blood flow. The A1 domain contains binding sites for both platelet glycoprotein Ibα and various collagen subtypes, enabling it to bridge platelets with the subendothelial matrix at sites of vascular injury. Its adhesive activity is tightly regulated by conformational changes induced by hydrodynamic forces or interaction with collagen, as well as by post-translational modifications and mutations associated with bleeding disorders. The A1 domain is the site of several naturally occurring mutations that cause von Willebrand disease type 2B and other pathological states. Therapeutics targeting VWF-A1 (such as caplacizumab) are used to treat thrombotic thrombocytopenic purpura but come with bleeding-related safety concerns due to inhibition of platelet function

Other names

vWF-A1VWF A1 domainvon Willebrand factor type A domain 1A1 domain of VWFVWFA1

Inhibit platelet GPIb binding to VWF-A1 domain to block platelet aggregation Modulate GPIb binding state through conformational changes (brought by drugs, mutations, or mechanical force)