title: Disruption of β-catenin binding to parathyroid hormone (PTH) receptor inhibits PTH-stimulated ERK1/2 activation.
abstract: The type I parathyroid hormone receptor (PTH1R) mediates PTH and PTH-related protein (PTHrP) actions on extracellular mineral ion homeostasis and bone remodeling. These effects depend in part on the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2). Sequences located within or at the carboxyl-terminus of PTH1R control its activation and trafficking. β-catenin regulates PTH1R signaling and promotes chondrocyte hypertrophy through binding to the intracellular carboxyl-terminal region of the receptor. How the interaction of PTH1R with β-catenin affects PTH-stimulated ERK1/2 is unknown. In the present study, human embryonic kidney 293 (HEK293) cells, which do not express the PTH1R, were used to investigate whether the disruption of β-catenin binding to PTH1R affects PTH-stimulated ERK1/2 activation. We demonstrated that β-catenin interacted with wild-type PTH1R but this interaction was markedly reduced with mutant PTH1R (L584A/L585A). PTH stimulated less cAMP formation and increased more intracellular calcium in HEK293 cells transfected with wild-type PTH1R compared with mutant PTH1R, indicating β-catenin switches PTH1R signaling from Gαs activation to Gαq signaling. In addition, ERK1/2 activation in HEK293 cells transfected with PTH1R exhibited time and concentration dependence. PTH-stimulated ERK1/2 activation was mostly mediated through Gαq/PLC signaling pathway. Importantly, transfection of mutant PTH1R decreased PTH-induced ERK1/2 activation by inhibiting Gαq-mediated signaling. This study shows for the first time that the interference of β-catenin binding to PTH1R inhibits PTH-stimulated ERK1/2 phosphorylation.
authors.affiliation: Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA. Electronic address: bin.wang@jefferson.edu.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
mesh_terms: D000262:Adenylyl Cyclases / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002864:Chromogranins; D000242:Cyclic AMP / Q000096:biosynthesis; D004789:Enzyme Activation; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D017136:Ion Transport; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D044168:Receptor, Parathyroid Hormone, Type 1 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*
chemical_list: C495270:CTNNB1 protein, human; D002864:Chromogranins; C554061:GNAQ protein, human; D044385:GTP-Binding Protein alpha Subunits; C473449:PTH1R protein, human; D010281:Parathyroid Hormone; D044168:Receptor, Parathyroid Hormone, Type 1; D051176:beta Catenin; D000242:Cyclic AMP; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D010738:Type C Phospholipases; C406732:GNAS protein, human; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D019205:GTP-Binding Protein alpha Subunits, Gs; D000262:Adenylyl Cyclases; D002118:Calcium
keywords: ERK1/2; G protein; Intracellular calcium; PTH1R; cAMP; β-catenin