PAI-1

PAI-1 (Plasminogen activator inhibitor-1, also known as SERPINE1) is a member of serine protease inhibitor (SERPIN) family that acts as the primary inhibitor of two main mammalian plasminogen activators, urinary-type (uPA) and tissue-type (tPA). As the main negative regulator of plasminogen activation, PAI-1 is an essential factor in regulation of the physiological balance between thrombosis and fibrinolysis. PAI-1 is a labile molecule that exists in four different forms: active, latent, cleaved and target bound form.

High PAI-1 levels are associated with many cardiovascular diseases. PAI-1 also plays important roles in cell migration, adhesion, senescence, cancer invasion and tissue remodeling. Moreover, the PAI-1 level was extensively validated as the biological prognostic factor in breast cancer and as a marker of a poor prognosis in other cancers. PAI-1 is also one of the plasma biomarkers associated with nonalcoholic fatty liver disease. These associations have made PAI-1 an attractive pharmaceutical target.