{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Integrins are integral cell-surface proteins composed of an alpha chain and a beta chain. A given chain may combine with multiple partners resulting in different integrins. CD61 (Integrin subunit beta 3) is a glycoprotein found on megakaryocytes (bone marrow cells), platelets and their precursors. CD61 plays a role in platelet aggregation and also as a receptor for fibrinogen, fibronectin, von Willebrand factor and vitronectin."}]}]}