CD41 is a 125/25 kD α subunit of the gpIIb/IIIa (CD41/CD61) complex. CD41 is a heterodimer composed of a heavy chain (gpIIbα) and light chain (gpIIbβ) linked by a single disulfide bond. It is a member of the integrin family primarily expressed on platelets and megakaryocytes. CD41 has been reported to be involved with platelet aggregation and platelet attachment to the ECM. CD41/CD61 complex acts as the receptor for fibrinogen, fibronectin, Von Willebrand factor and thrombin.