Characterization of Glucagon-Like Peptide-1 Receptor β-Arrestin 2 Interaction: A High-Affinity Receptor Phenotype

• Published in: Molecular endocrinology (Baltimore, Md.) Md.), 2005-03, Vol.19 (3), p.812-823
• Main Authors: Jorgensen, Rasmus, Martini, Lene, Schwartz, Thue W, Elling, Christian E
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Arrestins - chemistry; Arrestins - metabolism; beta-Arrestin 2; beta-Arrestins; Binding, Competitive; COS Cells; Cyclic AMP - metabolism; Dose-Response Relationship, Drug; Glucagon-Like Peptide-1 Receptor; Green Fluorescent Proteins - metabolism; GTP-Binding Proteins - metabolism; Humans; Kinetics; Ligands; Molecular Sequence Data; Phenotype; Protein Binding; Protein Conformation; Receptors, Glucagon - chemistry; Receptors, Glucagon - metabolism; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - metabolism; Sequence Homology, Amino Acid; Signal Transduction; Time Factors; Transfection
• ISSN: 0888-8809; 1944-9917
• DOI: 10.1210/me.2004-0312

To dissect the interaction between β-arrestin (βarr) and family B G protein-coupled receptors, we constructed fusion proteins between the glucagon-like peptide 1 receptor and βarr2. The fusion constructs had an increase in apparent affinity selectively for glucagon, suggesting that βarr2 interaction locks the receptor in a high-affinity conformation, which can be explored by some, but not all, ligands. The fusion constructs adopted a signaling phenotype governed by the tethered βarr2 with an attenuated G protein-mediated cAMP signal and a higher maximal internalization compared with wild-type receptors. This distinct phenotype of the fusion proteins can not be mimicked by coexpressing wild-type receptor with βarr2. However, when the wild-type receptor was coexpressed with both βarr2 and G protein-coupled receptor kinase 5, a phenotype similar to that observed for the fusion constructs was observed. We conclude that the glucagon-like peptide 1 fusion construct mimics the natural interaction of the receptor with βarr2 with respect to binding peptide ligands, G protein-mediated signaling and internalization, and that this distinct molecular phenotype is reminiscent of that which has previously been characterized for family A G protein-coupled receptors, suggesting similarities in the effect of βarr interaction between family A and B receptors also at the molecular level.