PROTEASE ACTIVATED RECEPTORS: AN EMERGING FAMILY OF GPROTEIN COUPLED RECEPTORS

Classically, cell surface receptors are activated by lig and binding. This interaction induces a conformational change in the receptor that results in a signal being trans mitted across the cell membrane. The activation is reversible in that the ligand can dissociate from its recep tor. Seven transmembrane domain Gprotein coupled receptors (GPCR) are perhaps the most important and wellcharacterized type of receptor, providing the basis for numerous pharmacological interventions. In recent years, it has become clear that GPCRs mediate the actions of almost all types of chemical messengers from small transmitters (catecholamines, histamine, acetyl choline, etc.), lipid messengers (prostaglandins, leukotrienes, platelet activating factor, etc.), neuropep tides (opiates, neuropeptide Y, tachykinins, etc.), peptid