Agonist-specific regulation of parathyroid hormone (PTH) receptor type 2 activity: structural and functional analysis of PTH- and tuberoinfundibular peptide (TIP) 39-stimulated desensitization and internalization.
The human PTH receptor type 2 (PTH2R) is activated by PTH and tuberoinfundibular peptide of 39 residues (TIP39), resulting in cAMP and intracellular Ca signaling. We now report that, despite these similarities, PTH and TIP39 elicit distinct responses from PTH2R. First, TIP39 induced beta-arrestin and protein kinase Cbeta mobilization and receptor internalization, whereas PTH did not. However, PTH stimulated trafficking of these molecules for a chimeric PTH2R containing the N terminus and third extracellular loop of PTH receptor type 1 (PTH1R). Second, whereas PTH-stimulated cAMP activity was brief and rapidly resensitized, the response to TIP39 was sustained and partly desensitized for a prolonged period. PTH2R desensitization was mediated by beta-arrestin interaction with the C terminus (amino acids 426-457) of PTH2R, whereas beta-arrestin mobilization had a minor influence on PTH2R internalization in response to TIP39, as shown with C terminus deletion mutants and/or dominant negative forms of beta-arrestin and dynamin. These data contrast with PTH1R, at which these dominant negative mutants markedly inhibited receptor internalization. Collectively, these results further highlight how specific interactions within the ligand-receptor bimolecular complex mediate distinct postactivation responses of class II G protein- coupled receptors and provide novel insights into the physiological regulation of PTH2R activity.
Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
Alessandro
A
Bisello
Danielle
D
Manen
Dominique D
DD
Pierroz
Ted B
TB
Usdin
René
R
Rizzoli
Serge L
SL
Ferrari
D000595:Amino Acid Sequence; D000818:Animals; D019390:Arrestins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism; D034281:Dynamins / Q000378:metabolism; D004705:Endocytosis; D005799:Genes, Dominant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008969:Molecular Sequence Data; D009154:Mutation; D010281:Parathyroid Hormone / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism; D064546:Protein Kinase C beta; D017434:Protein Structure, Tertiary; D051381:Rats; D044183:Receptor, Parathyroid Hormone, Type 2 / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013696:Temperature; D013997:Time Factors; D000071557:beta-Arrestins
D019390:Arrestins; D008024:Ligands; D010281:Parathyroid Hormone; D010455:Peptides; D044183:Receptor, Parathyroid Hormone, Type 2; D011993:Recombinant Fusion Proteins; D000071557:beta-Arrestins; D049452:Green Fluorescent Proteins; D000242:Cyclic AMP; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D034281:Dynamins; D002118:Calcium