Mutational and computational analysis of the alpha(1b)-adrenergic receptor. Involvement of basic and hydrophobic residues in receptor activation and G protein coupling.

Détails

ID Serval
serval:BIB_8CEB5BDDCCBA
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Mutational and computational analysis of the alpha(1b)-adrenergic receptor. Involvement of basic and hydrophobic residues in receptor activation and G protein coupling.
Périodique
Journal of Biological Chemistry
Auteur(s)
Greasley P.J., Fanelli F., Scheer A., Abuin L., Nenniger-Tosato M., DeBenedetti P.G., Cotecchia S.
ISSN
0021-9258 (Print)
ISSN-L
0021-9258
Statut éditorial
Publié
Date de publication
2001
Peer-reviewed
Oui
Volume
276
Numéro
49
Pages
46485-46494
Langue
anglais
Résumé
To investigate their role in receptor coupling to G(q), we mutated all basic amino acids and some conserved hydrophobic residues of the cytosolic surface of the alpha(1b)-adrenergic receptor (AR). The wild type and mutated receptors were expressed in COS-7 cells and characterized for their ligand binding properties and ability to increase inositol phosphate accumulation. The experimental results have been interpreted in the context of both an ab initio model of the alpha(1b)-AR and of a new homology model built on the recently solved crystal structure of rhodopsin. Among the twenty-three basic amino acids mutated only mutations of three, Arg(254) and Lys(258) in the third intracellular loop and Lys(291) at the cytosolic extension of helix 6, markedly impaired the receptor-mediated inositol phosphate production. Additionally, mutations of two conserved hydrophobic residues, Val(147) and Leu(151) in the second intracellular loop had significant effects on receptor function. The functional analysis of the receptor mutants in conjunction with the predictions of molecular modeling supports the hypothesis that Arg(254), Lys(258), as well as Leu(151) are directly involved in receptor-G protein interaction and/or receptor-mediated activation of the G protein. In contrast, the residues belonging to the cytosolic extensions of helices 3 and 6 play a predominant role in the activation process of the alpha(1b)-AR. These findings contribute to the delineation of the molecular determinants of the alpha(1b)-AR/G(q) interface.
Mots-clé
Amino Acid Sequence, Animals, COS Cells, Cricetinae, GTP-Binding Proteins/metabolism, Models, Molecular, Molecular Sequence Data, Mutagenesis, Polymerase Chain Reaction, Protein Conformation, Receptors, Adrenergic, alpha-1/chemistry, Receptors, Adrenergic, alpha-1/genetics
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 12:05
Dernière modification de la notice
08/05/2019 21:47
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