CELLULAR RECEPTORS FOR PLASMINOGEN ACTIVATORS - RECENT ADVANCES

The generation of the broad-specificity protease plasmin by the plasmi nogen activators urokinase-type plasminogen activator (uPA) and tissue -type plasminogen activator (tPA) is implicated in a variety of pathop hysiological processes, including vascular fibrin dissolution, extrace llular matrix degradation and remodeling, and cell migration. A mechan ism for the regulation of plasmin generation is through binding of the plasminogen activators to specific cellular receptors. uPA to the gly colipid-anchored membrane protein urokinase-type plasminogen activator receptor (uPAR) and tPA to a number of putative binding sites. The uP A-uPAR complex can interact with a variety of ligands, including plasm inogen, vitronectin, and integrins, indicating a multifunctional role for uPAR, regulating not only efficient and spatially restricted plasm in generation but also having the potential to modulate cell adhesion and signal transduction. The cellular binding of tPA, although less we ll characterized, also has the capacity to regulate plasmin generation and to play a significant role in vessel-wall biology. (C) 1997, Else vier Science Inc.