Urokinase receptor: a molecular organizer in cellular communication

In a variety of cell types, the glycolipid-anchored urokinase receptor (uPA R) is colocalized pericellularly with components of the plasminogen activat ion system and endocytosis receptors, uPAR is also coexpressed with caveoli n and members of the integrin adhesion receptor superfamily. The formation of functional units with these various proteins allows the uPAR to mediate the focused proteolysis required for cell migration and invasion and to con tribute both directly and indirectly to cell adhesive processes in a non-pr oteolytic fashion. This dual activity, together with the initiation of sign al transduction pathways by uPAR, is believed to influence cellular behavio ur in angiogenesis, inflammation, wound repair and tumor progression/metast asis and open up the way for uPAR-based therapeutic approaches.