Platelet glycoprotein Ib alpha chain also known as glycoprotein Ib (platelet), alpha polypeptide or CD42b (Cluster of Differentiation 42b), is a protein that in humans is encoded by the GP1BA gene. Glycoprotein Ib (GPIb) is a platelet surface membrane glycoprotein composed of a heterodimer, an alpha chain and a beta chain, that are linked by disulfide bonds. The GpIb functions as a receptor for von Willebrand factor (VWF). The complete receptor complex includes noncovalent association of the alpha and beta subunits with platelet glycoprotein IX and platelet glycoprotein V to form the glycoprotein Ib-IX-V complex. The binding of the GP Ib-IX-V complex to VWF facilitates initial platelet adhesion to vascular subendothelium after vascular injury, and also initiates signaling events within the platelet that lead to enhanced platelet activation, thrombosis, and hemostasis.
中文
