Catechol-binding serines of beta(2)-adrenergic receptors control the equilibrium between active and inactive receptor states.

Détails

ID Serval
serval:BIB_C40880BCF79C
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Catechol-binding serines of beta(2)-adrenergic receptors control the equilibrium between active and inactive receptor states.
Périodique
Molecular Pharmacology
Auteur(s)
Ambrosio C., Molinari P., Cotecchia S., Costa T.
ISSN
0026-895X (Print)
ISSN-L
0026-895X
Statut éditorial
Publié
Date de publication
2000
Volume
57
Numéro
1
Pages
198-210
Langue
anglais
Résumé
The binding free energy for the interaction between serines 204 and 207 of the fifth transmembrane helix of the beta(2)-adrenergic receptor (beta(2)-AR) and catecholic hydroxyl (OH) groups of adrenergic agonists was analyzed using double mutant cycles. Binding affinities for catecholic and noncatecholic agonists were measured in wild-type and mutant receptors, carrying alanine replacement of the two serines (S204A, S207A beta(2)-AR), a constitutive activating mutation, or both. The free energy coupling between the losses of binding energy attributable to OH deletion from the ligand and from the receptor indicates a strong interaction (nonadditivity) as expected for a direct binding between the two sets of groups. However, we also measured a significant interaction between the deletion of OH groups from the receptor and the constitutive activating mutation. This suggests that a fraction of the decrease in agonist affinity caused by serine mutagenesis may involve a shift in the conformational equilibrium of the receptor toward the inactive state. Direct measurements using a transient transfection assay confirm this prediction. The constitutive activity of the (S204A, S207A) beta(2)-AR mutant is 50 to 60% lower than that of the wild-type beta(2)-AR. We conclude that S204 and S207 do not only provide a docking site for the agonist, but also control the equilibrium of the receptor between active (R*) and inactive (R) forms.
Mots-clé
Amino Acid Substitution, Animals, COS Cells, Catechols/metabolism, Cloning, Molecular, Gene Deletion, Hydroxylation, Ligands, Mutagenesis, Receptors, Adrenergic, beta-2/genetics, Receptors, Adrenergic, beta-2/metabolism, Serine/genetics, Serine/metabolism, Signal Transduction/physiology, Thermodynamics
Pubmed
Web of science
Création de la notice
24/01/2008 11:05
Dernière modification de la notice
20/08/2019 15:39
Données d'usage