Heterologous desensitization of the glucagon-like peptide-1 receptor by phorbol esters requires phosphorylation of the cytoplasmic tail at four different sites.

Détails

ID Serval
serval:BIB_10E24D1AAEDB
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Heterologous desensitization of the glucagon-like peptide-1 receptor by phorbol esters requires phosphorylation of the cytoplasmic tail at four different sites.
Périodique
Journal of Biological Chemistry
Auteur(s)
Widmann C., Dolci W., Thorens B.
ISSN
0021-9258[print], 0021-9258[linking]
Statut éditorial
Publié
Date de publication
1996
Volume
271
Numéro
33
Pages
19957-19963
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Résumé
Glucagon-like peptide-1 stimulates glucose-induced insulin secretion by binding to a specific G protein-coupled receptor that activates the adenylyl cyclase pathway. We previously demonstrated that heterologous desensitization of the receptor by protein kinase C correlated with phosphorylation in a 33-amino acid-long segment of the receptor carboxyl-terminal cytoplasmic tail. Here, we determined that the in vivo sites of phosphorylation are four serine doublets present at positions 431/432, 441/442, 444/445, and 451/452. In vitro phosphorylation of fusion proteins containing mutant receptor C-tails, however, indicated that whereas serines at position 431/432 were good substrates for protein kinase C (PKC), serines 444/445 and 451/452 were poor substrates, and serines 441/442 were not substrates. In addition, serine 416 was phosphorylated on fusion protein but not in intact cells. This indicated that in vivo a different PKC isoform or a PKC-activated kinase may phosphorylate the receptor. The role of phosphorylation on receptor desensitization was assessed using receptor mutants expressed in COS cells or Chinese hamster lung fibroblasts. Mutation of any single serine doublet to alanines reduced the extent of phorbol 12-myristate 13-acetate-induced desensitization, whereas substitution of any combination of two serine doublets suppressed it. Our data thus show that the glucagon-like peptide-1 receptor can be phosphorylated in response to phorbol 12-myristate 13-acetate on four different sites within the cytoplasmic tail. Furthermore, phosphorylation of at least three sites was required for desensitization, although maximal desensitization was only achieved when all four sites were phosphorylated.
Mots-clé
Amino Acid Sequence, Animals, Cells, Cultured, Cercopithecus aethiops, Cricetinae, Cricetulus, Cytoplasm/metabolism, DNA Mutational Analysis, Down-Regulation, Glucagon-Like Peptide 1, Molecular Sequence Data, Peptides/metabolism, Phosphorylation, Phosphoserine/metabolism, Protein Kinase C/metabolism, Rats, Receptors, Glucagon/metabolism, Signal Transduction, Tetradecanoylphorbol Acetate/pharmacology, Transfection
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 14:43
Dernière modification de la notice
20/08/2019 12:38
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