Cellular receptors in the regulation of plasmin generation.

Cell surface receptors may play a significant role in the regulation of plasmin generation. Although structurally diverse, these receptors can be classified on a functional basis into two groups. Activation receptors for plasminogen and plasminogen activators serve to localize, and in some cases, potentiate plasminogen activation, and are expressed on endothelial cells, blood cells, neuronal cells, and tumor cells. Clearance receptors, on the other hand, serve to eliminate plasmin and plasminogen activators from blood or focal micro-environments. They are found primarily on parenchymal hepatocytes and tissue macrophages. It is likely that integrated actions of both classes of receptors are essential to the homeostatic control of plasmin activity. Knowledge of how these receptors themselves are regulated may provide an important key to understanding a host of biologic processes.