MolPharm xPharm- The Comprehensive Pharmacology Reference

Home Help [Feedback] [For Subscribers] [Archive] [Search] --
QUICK SEARCH:   [advanced]


     

Molecular Pharmacology Fast Forward
First published on June 4, 2008; DOI: 10.1124/mol.108.047472

This Article
Right arrow Full Text (PDF)
Right arrow Data Supplement
Right arrow All Versions of this Article:
mol.108.047472v1
74/3/544    most recent
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Author home page(s):
Chang-Deng Hu
Val J. Watts
Google Scholar
Right arrow Articles by Vidi, P.-A.
Right arrow Articles by Watts, V. J.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Vidi, P.-A.
Right arrow Articles by Watts, V. J.


Received for publication March 27, 2008.
Revised June 4, 2008.
Accepted for publication June 4, 2008.

Ligand-Dependant Oligomerization of Dopamine D2 and Adenosine A2A Receptors in Living Neuronal Cells

Pierre-Alexandre Vidi 1, Benjamin R. Chemel 1, Chang-Deng Hu 1, Val J. Watts 1*

1 Purdue University

* Address correspondence to: E-mail: wattsv{at}pharmacy.purdue.edu

Abstract

Adenosine A2A and dopamine D2 receptors (A2A and D2) associate in homo- and heteromeric complexes in the striatum, providing a structural basis for their mutual antagonism. At the cellular level, the portion of receptors engaging in homo- and heteromers, as well as the effect of persistent receptor activation or antagonism on the cell oligomer repertoire, are largely unknown. We have used bimolecular fluorescence complementation (BiFC) to visualize A2A and D2 oligomerization in the Cath.a differentiated neuronal cell model. Receptor fusions to BiFC fluorescent protein fragments retained their function when expressed alone, or in A2A/A2A, D2/D2, and A2A/D2 BiFC pairs. Robust fluorescence complementation reflecting A2A/D2 heteromers was detected at the cell membrane as well as in endosomes. In contrast, weaker BiFC signals, largely confined to intracellular domains, were detected with A2A/dopamine D1 BiFC pairs. Multicolor BiFC was used to simultaneously visualize A2A and D2 homo- and heteromers in living cells and to examine drug-induced changes in receptor oligomers. Prolonged D2 stimulation with quinpirole lead to the internalization of D2/D2 and A2A/D2 oligomers, and resulted in decreased A2A/D2 relative to A2A/A2A oligomer formation. Opposing effects were observed in cells treated with D2 antagonists or with the A2A agonist MECA. Subsequent radioreceptor binding analysis indicated that the drug-induced changes in oligomer formation were not readily explained by alterations in receptor density. These observations support the hypothesis that chronic drug exposure differentially alters A2A/D2 receptor oligomerization and provide the first demonstration for the use of BiFC to monitor drug-modulated GPCR oligomerization.


Key words: Adenosine, Dopamine, cAMP, Receptor synthesis/trafficking, Fluorescence techniques, Receptor binding studies




Home Help [Feedback] [For Subscribers] [Archive] [Search] --
All ASPET Journals Molecular Pharmacology Pharmacological Reviews
Molecular Interventions Drug Metabolism and Disposition

Copyright © 2008 by the American Society for Pharmacology and Experimental Therapeutics