<prompt> All are TRUE about protease activated receptors, EXCEPT:Family of three seven transmembrane proteinActivated by thrombinReleases PGE2Protects epithelial cells  <response>: Protease activated receptors PARs, a family of four seven-transmembrane G protein-coupled receptors PAR1, PAR2, PAR3, PAR4, act as targets for signalling by various proteolytic enzymes thrombin, trypsin. PARs are characterized by a unique activation mechanism involving the proteolytic unmasking of a tethered ligand that stimulates the receptor. They release PGE2 and this inturn protects the epithelium. Ref: Ganongs Review of Medical Physiology, 21st Edition, Page 667 