The dual role of the urokinase receptor system in pericellular proteolysisand cell adhesion: implications for cardiovascular function

Cell-cell and cell-matrix interactions are key events in morphogenetic proc esses during development and tissue remodelling. In the vascular system, ov erexpression of adhesion receptors such as integrins, protease (receptors) or dysregulation of adhesive interactions are directly related to the patho physiology of cardiovascular diseases (atherosclerosis, restenosis, thrombo sis) or angiogenesis-driven tumor progression. Protease cascades such as th e plasminogen activation system exhibit a dual role in cell invasion by pro moting pericellular proteolysis as well as by regulating cell adhesion and migration in a non-proteolytic fashion. In both these mechanisms, the uroki nase receptor (uPAR) plays a central role and may become engaged in complex es with beta(1)-, beta(2)-, and beta(3)-integrins. This article will focus on the molecular and functional interactions between the uPAR system and va scular integrins and discuss implications for cardiovascular function.