Orexin-1 receptor-cannabinoid CB1 receptor heterodimerization results in both ligand-dependent and -independent coordinated alterations of receptor localization and function

Ellis, J., Pediani, J.D. , Canals Buj, M., Milasta, S. and Milligan, G. (2006) Orexin-1 receptor-cannabinoid CB1 receptor heterodimerization results in both ligand-dependent and -independent coordinated alterations of receptor localization and function. Journal of Biological Chemistry, 281(25), pp. 38812-38824. (doi:10.1074/jbc.M602494200)

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Publisher's URL: http://dx.doi.org/10.1074/jbc.M602494200

Abstract

Following inducible expression in HEK293 cells, the human orexin-1 receptor was targeted to the cell surface but became internalized following exposure to the peptide agonist orexin A. By contrast, constitutive expression of the human cannabinoid CB1 receptor resulted in a predominantly punctate, intracellular distribution pattern consistent with spontaneous, agonistindependent internalization. Expression of the orexin-1 receptor in the presence of the CB1 receptor resulted in both receptors displaying the spontaneous internalization phenotype. Single cell fluorescence resonance energy transfer imaging indicated the two receptors were present as heterodimers/oligomers in intracellular vesicles. Addition of the CB1 receptor antagonist SR-141716A to cells expressing only the CB1 receptor resulted in re-localization of the receptor to the cell surface. Although SR-141716A has no significant affinity for the orexin-1 receptor, in cells co-expressing the CB1 receptor, the orexin-1 receptor was also re-localized to the cell surface by treatment with SR-141716A. Treatment of cells co-expressing the orexin-1 and CB1 receptors with the orexin-1 receptor antagonist SB-674042 also resulted in re-localization of both receptors to the cell surface. Treatment with SR-141716A resulted in decreased potency of orexin A to activate the mitogen-activated protein kinases ERK1/2 only in cells co-expressing the two receptors. Treatment with SB-674042 also reduced the potency of a CB1 receptor agonist to phosphorylate ERK1/2 only when the two receptors were co-expressed. These studies introduce an entirely novel pharmacological paradigm, whereby ligands modulate the function of receptors for which they have no significant inherent affinity by acting as regulators of receptor heterodimers.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Pediani, Dr John and Milligan, Professor Graeme and Canals Buj, Dr Meritxell
Authors: Ellis, J., Pediani, J.D., Canals Buj, M., Milasta, S., and Milligan, G.
Subjects:Q Science > QH Natural history > QH345 Biochemistry
College/School:College of Medical Veterinary and Life Sciences
College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Journal of Biological Chemistry
Journal Abbr.:J Biol Chem.
Publisher:American Society for Biochemistry and Molecular Biology, Inc.
ISSN:0021-9258
ISSN (Online):1083-351X
Copyright Holders:Copyright © 2006 American Society for Biochemistry and Molecular Biology
First Published:First published in Journal of Biological Chemistry 281(25):38812-38824

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
242491Quantitative Analysis of the Effects of Receptor and G-Protein Mutations and Polymorphisms on Signal InitiationGraeme MilliganMedical Research Council (MRC)G9811527Institute of Neuroscience and Psychology
242492Quantitative Analysis of the Effects of Receptor and G-Protein Mutations and Polymorphisms on Signal InitiationGraeme MilliganMedical Research Council (MRC)G9811527Institute of Neuroscience and Psychology
389781The quaternary structure of G-protein coupled receptors - implications for function drug design. Programme grant support renewalGraeme MilliganMedical Research Council (MRC)G9811527Institute of Neuroscience and Psychology