ABSTRACT
The capacity of platelets to adhere to other platelets and to specific elements within the extracellular matrix is a control point for the maintenance of normal hemostasis. The membrane glycoprotein αIIbβ3 complex plays a central role in the aggregation response by mediating the interaction of platelets with fibrinogen and other adhesive proteins in plasma including fibronectin and the von Willebrand factor. Morphology of the αIIbβ3 complex has been investigated by electron microscopy utilizing rotary shadowing. The biosynthetic pathway leading to surface expression of αIIbβ3 have been studied in cell-free translation systems with mRNA derived from the human erythroleukemic cell line and human megakaryocytes. The binding of adhesive proteins to αIIbβ3 has been extensively reviewed. The identification of the domain(s) within αIIbβ3 that mediate its interactions with fibrinogen as well as other adhesive proteins have utilized several approaches. The ligand recognition sites of αIIbβ3 can be further characterized by the identification of mutations which disrupt ligand binding.
