How does the coagulation protease thrombin regulate cellular behaviour? The
protease-activated receptors (PARs) provide one answer. In concert with th
e coagulation cascade, these receptors provide an elegant mechanism linking
mechanical information in the form of tissue injury or vascular leakage to
cellular responses. Roles for PARs are beginning to emerge in haemostasis
and thrombosis, inflammation, and perhaps even blood vessel development.