CD42b is a 145 kDa glycoprotein, also known as gpIbα. It forms a covalent linkage with CD42c to constitute the GPIb complex. CD42b is expressed on platelets and megakaryocytes. The CD42b/c heterodimer assembles with CD42a and CD42d to form a larger complex, which functions as a platelet receptor for von Willebrand factor (vWF) and thrombin.
