The human urokinase-type plasminogen activator receptor (uPAR) is a 55-65 kDa, highly glycosylated, GPI-anchored cell surface receptor (the deglycosylated protein is 35 kDa). It is a central player in the plasminogen activation pathway. uPAR binds with high affinity to a serine protease urokinase-type plasminogen activator (uPA) and converts plasminogen to its active form plasmin in a spatially restricted manner on the cell surface. Plasmin further carries out the activation of uPA, which is inhibited by serpins, such as plasminogen activator inhibitors. Therefore, uPAR plays a key role in regulating extracellular proteolysis. In addition, uPAR plays an important role in regulating cell proliferation, adhesion, and mobility. Research studies have shown that overexpression of uPAR is found in various cancer cells and tissues.
