Integrin alpha V chain interacts with the integrin beta 3 subunit/CD61 to form the alpha-V-beta-3 heterodimer/vitronectin receptor. It is expressed on endothelial cells, some activated leukocytes, NK cells, macrophages, neutrophils, and platelets. Integrin alpha V also forms heterodimers with the integrin beta 1, beta 5, beta 6, and beta 8 subunits. Alpha-V-beta-3 is an activation dependent receptor for platelet attachment and spreading on vitronectin and other matrix components.