All are TRUE about protease activated receptors, EXCEPT:: (A) Family of three seven transmembrane protein, (B) Activated by thrombin, (C) Releases PGE2, (D) Protects epithelial cells
Answer is A. 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: Ganong's Review of Medical Physiology, 21st Edition, Page 667