The integrins are a superfamily of cell adhesion receptors that bind to extracellular matrix ligands, cell-surface ligands, and soluble ligands (PMID: 17543136). They are transmembrane αβ heterodimers and at least 24 distinct integrin heterodimers are formed by the combination of 18 α and eight β known subunits (PMID: 17543136; 20029421). In addition to mediating cell adhesion, integrins also play important roles in modulating signal transduction pathways that control cellular responses, including migration, proliferation, differentiation, and apoptosis (PMID: 19118207). Integrin alpha-IIb (ITGA2B, CD41) is expressed on platelets, megakaryocytes and some hematopoietic progenitor cells (PMID: 11934866). This protein undergoes post-translational cleavage to yield disulfide linked light beta (25 kDa) and heavy alpha (125 kDa) chains, which join with integrin beta3 (CD61) to form a receptor for fibronectin, fibrinogen, plasminogen, prothrombin, thrombospondin and vitronectin. CD41/CD61 is crucial for platelet aggregation through binding of soluble fibrinogen. Jurkat and U937 cell lines are negative controls for CD41 (PMID: 2351656).