Coaggregation, Cointernalization, and Codesensitization of Adenosine A2A Receptors and Dopamine D2Receptors*
- Joëlle Hillion‡§¶,
- Meritxell Canals‡§,
- Maria Torvinen‡,
- Vicent Casadó‖,
- Rizaldy Scott‡,
- Anton Terasmaa‡,
- Anita Hansson‡,
- Stanley Watson**,
- Mark E. Olah‡,
- Josefa Mallol‖,
- Enric I. Canela‖,
- Michele Zoli§§,
- Luigi F. Agnati§§,
- Carlos F. Ibáñez‡,
- Carme Lluis‖,
- Rafael Franco‖,
- Sergi Ferr釶¶ and
- Kjell Fuxe‡
- From the ‡Department of Neuroscience, Karolinska Institute, 17177 Stockholm, Sweden, the ‖Department of Biochemistry and Molecular Biology, University of Barcelona, 08028 Barcelona, Spain, the **Mental Health Institute, University of Michigan, Ann Arbor, Michigan 48109, the‡Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, the§§Department of Biomedical Sciences, University of Modena, 41100 Modena, Italy, and the ¶¶National Institute on Drug Abuse, Baltimore, Maryland 21224
Abstract
Antagonistic and reciprocal interactions are known to exist between adenosine and dopamine receptors in the striatum. In the present study, double immunofluorescence experiments with confocal laser microscopy showed a high degree of colocalization of adenosine A2A receptors (A2AR) and dopamine D2 receptors (D2R) in cell membranes of SH-SY5Y human neuroblastoma cells stably transfected with human D2R and in cultured striatal cells. A2AR/D2R heteromeric complexes were demonstrated in coimmunoprecipitation experiments in membrane preparations from D2R-transfected SH-SY5Y cells and from mouse fibroblast Ltk− cells stably transfected with human D2R (long form) and transiently cotransfected with the A2AR double-tagged with hemagglutinin. Long term exposure to A2AR and D2R agonists in D2R-cotransfected SH-SY5Y cells resulted in coaggregation, cointernalization and codesensitization of A2AR and D2R. These results give a molecular basis for adenosine-dopamine antagonism at the membrane level and have implications for treatment of Parkinson's disease and schizophrenia, in which D2R are involved.
Footnotes
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↵* This work was supported by Swedish Medical Research Council Grant 14X-00715, European Commission Grant QLG3-CT-2001-01056, Spanish Commission of Science and Technology National Plan of Biotechnology Grant BIO99-0601-C02-02), an Italian Ministero della Università e della Ricerca Scientifica e Tecnologica ex60% grant, and a grant from the Knut and Alice Wallenberg Foundation.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵§ These authors contributed equally to this manuscript.
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↵¶ To whom correspondence should be addressed. Present address: Stroke Branch, NINDS, National Institutes of Health, Bethesda, MD 20892-4128. Tel.: 301-594-2597; Fax: 301-402-2769; E-mail: hillionj@ninds.nih.gov.
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Published, JBC Papers in Press, February 28, 2002, DOI 10.1074/jbc.M107731200
- Abbreviations:
- D2R
-
dopamine D2 receptor
- A2AR
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adenosine A2A receptor
- HA
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hemagglutinin
- ANOVA
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analysis of variance
- PBS
-
phosphate-buffered saline
- FITC
-
fluorescein isothiocyanate
- IR
-
immunoreactive
- GI
-
Gini's index
- DOPA
-
3,4-dihydroxyphenylalanine
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- Received August 13, 2001.
- Revision received January 22, 2002.
- The American Society for Biochemistry and Molecular Biology, Inc.
