Functional homomers and heteromers of dopamine D_2L and D₃ receptors co-exist at the cell surface

Pou, C., Mannoury la Cour, C., Stoddart, L.A., Millan, M.J. and Milligan, G. (2012) Functional homomers and heteromers of dopamine D_2L and D₃ receptors co-exist at the cell surface. Journal of Biological Chemistry, 287(12), pp. 8864-8878. (doi: 10.1074/jbc.M111.326678)

Abstract

Human dopamine D_2long and D₃ receptors were modified by N-terminal addition of SNAP or CLIP forms of C⁶-alkylguanine-DNA-alkyltransferase plus a peptide epitope tag. Cells able to express each of these four constructs only upon addition of an antibiotic were established and used to confirm regulated and inducible control of expression, the specificity of SNAP and CLIP tag covalent labeling reagents, and based on homogenous time-resolved fluorescence resonance energy transfer, the presence of cell surface D_2long and D₃ receptor homomers. Following constitutive expression of reciprocal constructs, potentially capable of forming and reporting the presence of cell surface D_2long-D₃ heteromers, individual clones were assessed for levels of expression of the constitutively expressed protomer. This was unaffected by induction of the partner protomer and the level of expression of the partner required to generate detectable cell surface D_2long–D₃ heteromers was defined. Such homomers and heteromers were found to co-exist and using a reconstitution of function approach both homomers and heteromers of D_2long and D₃ receptors were shown to be functional, potentially via trans-activation of associated G protein. These studies demonstrate the ability of dopamine D_2long and D₃ receptors to form both homomers and heteromers, and show that in cells expressing each subtype a complex mixture of homomers and heteromers co-exists at steady state. These data are of potential importance both to disorders in which D_2long and D₃ receptors are implicated, like schizophrenia and Parkinson disease, and also to drugs exerting their actions via these sites.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Millan, Dr Mark and Milligan, Professor Graeme and Pou, Dr Chantevy
• Authors: Pou, C., Mannoury la Cour, C., Stoddart, L.A., Millan, M.J., and Milligan, G.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences; College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
• Journal Name: Journal of Biological Chemistry
• Journal Abbr.: J Biol Chem.
• ISSN: 0021-9258
• ISSN (Online): 1083-351X
• Published Online: 16 March 2012

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
					G0900050