title: Homologous and heterologous phosphorylations of human histamine H1 receptor in intact cells.
abstract: Homologous and heterologous phosphorylations of histamine H1 receptor (H1R) in intact cells were investigated using Chinese hamster ovary cells stably co-expressing c-myc-tagged human histamine H1 and muscarinic M3 receptors. Increase in histamine-induced homologous phosphorylation of H1R was induced in a dose- and time-dependent manner. Maximum phosphorylation of H1R by 8-fold over the basal level was induced 1 min after the stimulation, and the increased phosphorylation level was maintained over 40 min. M3 receptor-mediated heterologous phosphorylation of H1R reached maximum by 2-fold over the basal level at 5 min after the stimulation and then rapidly returned to the basal level by 40 min after the stimulation. Histamine-induced phosphorylation of H1R was partially inhibited by three protein kinase inhibitors including Ro-31-8220 for protein kinase C (PKC), KN-93 for calcium/calmodulin-dependent kinase II (CaMKII), and KT5823 for protein kinase G (PKG), while, M3-receptor-mediated phosphorylation of H1R was completely inhibited by Ro 31-8220. Protein kinase activators including phorbol 12-myristate 13-acetate (PMA), 8-bromo-cyclic GMP (8-Br-cGMP), and 8-bromo-cyclic AMP (8-Br-cAMP) induced increases in H1R phosphorylation. Increased phosphorylation of H1R, by 5-fold over the basal level, induced with a combination of PMA, 8-Br-cGMP, and 8-Br-cAMP was still lower than that with histamine. It was suggested that H1R-mediated H1R phosphorylation involves the activation of PKC, CaMKII, PKG, and other unidentified kinases including G-protein coupled receptor kinases (GRKs) and that PKC is solely involved in M3 receptor-mediated H1R phosphorylation.
authors.affiliation: Department of Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokushima, Tokushima 770-8505, Japan.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Miyoshi
authors.forename: Nozomi
authors.initials: N
authors.lastname: Kawakami
authors.forename: Shuhei
authors.initials: S
authors.lastname: Horio
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fukui
mesh_terms: D000818:Animals; D016466:CHO Cells; D002217:Carbachol / Q000494:pharmacology; D006224:Cricetinae; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000494:pharmacology; D010766:Phosphorylation; D011738:Pyrilamine / Q000378:metabolism; D043587:Receptor, Muscarinic M3 / Q000032:analysis; D011969:Receptors, Histamine H1 / Q000032:analysis / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D043587:Receptor, Muscarinic M3; D011969:Receptors, Histamine H1; C015482:protein kinase modulator; C016276:8-bromocyclic GMP; D006632:Histamine; D002217:Carbachol; D006152:Cyclic GMP; D011738:Pyrilamine; D013755:Tetradecanoylphorbol Acetate