Urokinase-type plasminogen activator (uPA) (uPA)

Urokinase-type plasminogen activator (uPA) is a serine protease that serves as a key initiator of the plasminogen activation cascade, converting inactive plasminogen into plasmin (UniProt P00749). The biological activity of uPA is significantly amplified and localized when it binds to the urokinase-type plasminogen activator receptor (uPAR), a GPI-anchored protein on the cell surface (PubMed: 12114520). This uPA/uPAR complex facilitates the degradation of the extracellular matrix (ECM), which is essential for physiological processes like wound healing but also drives pathological processes such as tumor cell invasion and metastasis (PubMed: 25650595). In oncology, high expression of uPA and its inhibitor PAI-1 are established prognostic biomarkers used to identify patients with high-risk breast cancer who may benefit from chemotherapy (ASCO Guidelines). Therapeutic strategies targeting this complex include small-molecule inhibitors of uPA's catalytic activity, such as Upamostat, and agents designed to disrupt the uPA-uPAR interaction to inhibit cell migration and signaling. Despite its potential, targeting the uPA/uPAR system requires careful management of safety concerns related to its role in normal fibrinolysis and tissue repair.

Other names

PLAUUrokinasePlasminogen activator, urinary-typeu-PAuPA/uPAR complex

Inhibition of serine protease activity to prevent plasminogen activation; disruption of the uPA-uPAR protein-protein interaction to prevent localized proteolysis and signaling.