UPAR (Urokinase plasminogen activator receptor) is a glycoprotein I anchored surface receptor specific for urokinase plasminogen activator (uPA). Upon binding to uPAR, uPA converts the surface bound, large serum beta globulin plasminogen to plasmin. Plasmin, which is also designated fibrinolysin, is a trypsin like enzyme that acts on Arg-Lys bonds and induces pericellular proteolysis in fibrin and fibrinogen, and thereby contributes to the systematic activation of the coagulation cascade. uPA and uPAR are known to be overexpressed in mesenchymal and epithelial tumor cells and are required for tumor invasion and metastasis.Synonyms: MO3, Monocyte activation antigen Mo3, PLAUR, U-PAR, Urokinase plasminogen activator surface receptor