title: Properties of chimeric prostacyclin/prostaglandin D2 receptors: site-directed mutagenesis reveals the significance of the isoleucine residue at position 323.
abstract: Mouse prostacyclin (mIP) receptors transiently expressed in Chinese hamster ovary (CHO) cells activated both adenylyl cyclase and phospholipase C, with a 33-fold preference for signaling through Gs. The prostacyclin (IP) receptor agonists cicaprost, iloprost, carbacyclin, and prostaglandin E1 showed a similar order of potency for activation of both signaling pathways in cells transiently transfected with the mIP and the chimeric prostacyclin/prostaglandin D2 (IPN-VII/DPC and IPN-V/DPVI-C) receptors. Substitution of the carboxyl-terminal tail of the prostacyclin receptor with the corresponding region of the mDP receptor (IPN-VII/DPC) produced a receptor with increased coupling to both Gs and Gq. However, this increased G-protein coupling was lost in the IPN-V/DPVI-C receptor. The observation that both these chimeric receptors can activate phospholipase C indicates that the carboxyl-terminal tail of the IP receptor is not entirely responsible for its ability to couple to Gq. Site-directed mutagenesis studies suggest that isoleucine at position 323 in the IPN-VII/DPC receptor plays an important role in mediating the increased potency of this chimeric receptor.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China. helenwise@cuhk.edu.hk
authors.forename: Helen
authors.initials: H
authors.lastname: Wise
authors.forename: Kevin B S
authors.initials: KB
authors.lastname: Chow
authors.forename: Kam Yiu
authors.initials: KY
authors.lastname: Wing
authors.forename: Takuya
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Dicky L Y
authors.initials: DL
authors.lastname: Tse
authors.forename: Christopher H K
authors.initials: CH
authors.lastname: Cheng
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D004789:Enzyme Activation; D016285:Iloprost / Q000378:metabolism; D066298:In Vitro Techniques; D007532:Isoleucine / Q000737:chemistry; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D044006:Receptors, Epoprostenol / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D044006:Receptors, Epoprostenol; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin; D011993:Recombinant Fusion Proteins; D007532:Isoleucine; D010738:Type C Phospholipases; D000262:Adenylyl Cyclases; D016285:Iloprost; C036293:prostaglandin D2 receptor