FIGURE 1.

Schematic view of the platelet GP Ib-IX complex. The depicted polypeptide arrangement of GP Ibα, GP Ibβ, and GP IX is based on the recently published stoichiometry of 1:2:1 (3). Circles with S inside represent the extracellular disulfide linkage between GP Ibα and GP Ibβ. The intracellular membrane-proximal cysteines of GP Ibβ (Cys¹⁴⁸) and GP IX (Cys¹⁵⁴) were reported to be the potential sites for palmitate modification as shown (15). The dashed rectangle depicts either the GP Ibα ligand binding domain or the WM23 binding region (macroglycopeptide).