QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: jpet.106.101220v1 318/2/683    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Snook, L. A. Articles by Massotte, D. Search for Related Content PubMed PubMed Citation Articles by Snook, L. A. Articles by Massotte, D. Pubmed/NCBI databases Compound via MeSH Substance via MeSH

CELLULAR AND MOLECULAR

µ- Opioid Receptor Functional Interaction: Insight Using Receptor-G Protein Fusions

Département de Neurobiologie, Unité Mixte de Recherche 7104, Institut de Génétique et Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université Louis Pasteur, Illkirch, France (L.A.S., B.L.K., D.M.); and Molecular Pharmacology Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, United Kingdom (G.M.)

Fusion proteins between a receptor and a pertussis toxin-insensitive G_i subunit were used to gain insight into the molecular interactions that take place upon µ and opioid receptor heterodimerization. When µ opioid receptor-G_i1 fusions were coexpressed with nonfused opioid receptors in human embryonic kidney 293 cells, or vice versa, receptor heterodimers were detected by coimmunoprecipitation. In pertussis toxin-treated cells, receptor coexpression decreased the amount of guanosine 5'-O-(3-[³⁵S]thio)triphosphate ([³⁵S]GTPS) incorporated in the fused G protein after the addition of agonists specific for the receptor-G_i1 fusion. In addition, activation of the G protein occurred in heterodimers upon addition of an agonist specific for the nonfused receptor. It remained unaffected by an inverse agonist specific for the receptor-G_i1 fusion. These data suggest that signaling through the receptor-G_i1 fusion protein is impaired in heterodimers and support a mechanism in which activation of the G subunit is promoted by a direct interaction with the nonfused receptor. Alternatively, receptor coexpression did not modify the ligand binding properties for the high-affinity state of the receptor-G_i1 fusion nor the EC₅₀ values for agonist-induced [³⁵S]GTPS incorporation in the G_i1 subunit. In addition, no binding competition was observed between and µ ligands. Together, the data point to µ- opioid receptor heterodimers formed by contact interactions between monomers that retain their structural integrity.

Address correspondence to: Dr. Dominique Massotte, Unité Mixte de Recherche 7104, Institut de Génétique et Biologie Moléculaire et Cellulaire, 1 rue Laurent Fries BP 10142, F-67404 Illkirch cedex, France. E-mail: massotte{at}igbmc.u-strasbg.fr

This article has been cited by other articles:

				M. Damian, S. Mary, A. Martin, J.-P. Pin, and J.-L. Baneres G Protein Activation by the Leukotriene B4 Receptor Dimer: EVIDENCE FOR AN ABSENCE OF TRANS-ACTIVATION J. Biol. Chem., July 25, 2008; 283(30): 21084 - 21092. [Abstract] [Full Text] [PDF]