title: Differential regulation of the signaling and trafficking of the two prostaglandin D2 receptors, prostanoid DP receptor and CRTH2.
abstract: Prostaglandin D2 (PGD2) exerts its actions on two G protein-coupled receptors, the prostanoid DP receptor and CRTH2 (chemoattractant homologous receptor expressed on TH2 cells). Here, we characterize the regulation of the signaling and trafficking of the prostanoid DP receptor and CRTH2. Time-course and dose-response curves showed that both receptors expressed in HEK293 cells internalized maximally after 2 h of stimulation with 1 microM PGD2. Co-expression of the G protein-coupled receptor kinases GRK2, GRK5 or GRK6 increased agonist-induced internalization of CRTH2, while only GRK2 had an effect on the internalization of the prostanoid DP receptor. Protein kinase C (PKC) activation stimulated the internalization of both receptors. Interestingly, only PGD2-induced internalization of CRTH2, and not of prostanoid DP receptor, was decreased by inhibition of PKC or protein kinase A (PKA). Our data also indicate that CRTH2 is subjected to basal phosphorylation by PKA, which appears to be involved in CRTH2 internalization. Prostanoid DP receptor internalization was promoted by co-expression of arrestin-2 and -3, while the internalization of CRTH2 was increased by co-expression of arrestin-3 only. The detection of prostanoid DP receptor and CRTH2 internalization was reduced by the co-expression of Rab4 and Rab11, respectively, suggesting differential regulation of receptor recycling. Moreover, immunofluorescence microscopy experiments showed that the prostanoid DP receptor specifically co-localized with Rab4, and CRTH2 with Rab11. The signaling of the prostanoid DP receptor was regulated by GRK2 overexpression, while that of CRTH2 was modulated by overexpression of GRK2, -5 and -6. Our results show a differential regulation of the prostanoid DP receptor and CRTH2, two receptors for PGD2.
authors.affiliation: Division of Rheumatology, Département de Médecine, Faculté de Médecine and Centre de Recherche Clinique-Etienne Lebel, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Maxime A
authors.initials: MA
authors.lastname: Gallant
authors.forename: Deborah
authors.initials: D
authors.lastname: Slipetz
authors.forename: Emilie
authors.initials: E
authors.lastname: Hamelin
authors.forename: Moulay Driss
authors.initials: MD
authors.lastname: Rochdi
authors.forename: Sébastien
authors.initials: S
authors.lastname: Talbot
authors.forename: Artur J
authors.initials: AJ
authors.lastname: de Brum-Fernandes
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Parent
mesh_terms: D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D019085:Fluorescent Antibody Technique, Direct; D054769:G-Protein-Coupled Receptor Kinase 2; D054774:G-Protein-Coupled Receptor Kinase 5; D054768:G-Protein-Coupled Receptor Kinases; D006801:Humans; D007700:Kinetics; D008856:Microscopy, Fluorescence; D015230:Prostaglandin D2 / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D011982:Receptors, Prostaglandin / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D051552:beta-Adrenergic Receptor Kinases / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D020695:rab4 GTP-Binding Proteins / Q000378:metabolism; D000099193:rab11 GTP-Binding Proteins
chemical_list: D017868:Cyclic AMP-Dependent Protein Kinases; D054769:G-Protein-Coupled Receptor Kinase 2; D054774:G-Protein-Coupled Receptor Kinase 5; D054768:G-Protein-Coupled Receptor Kinases; D015230:Prostaglandin D2; D011493:Protein Kinase C; D017346:Protein Serine-Threonine Kinases; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin; D051552:beta-Adrenergic Receptor Kinases; D020691:rab GTP-Binding Proteins; D020695:rab4 GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C496567:GRK2 protein, human; C089176:G-protein-coupled receptor kinase 6; C517898:GRK5 protein, human; C036293:prostaglandin D2 receptor