Interactions between Calmodulin, Adenosine A2A, and Dopamine D2 Receptors

• Published in: The Journal of biological chemistry 2009-10, Vol.284 (41), p.28058-28068
• Main Authors: Navarro, Gemma, Aymerich, Marisol S., Marcellino, Daniel, Cortés, Antoni, Casadó, Vicent, Mallol, Josefa, Canela, Enric I., Agnati, Luigi, Woods, Amina S., Fuxe, Kjell, Lluís, Carmen, Lanciego, Jose Luis, Ferré, Sergi, Franco, Rafael
• Format: Article
• Language: English
• Subjects: Adenosina; Adenosine; Adenosine - metabolism; Amino Acid Sequence; Animals; Calmodulin - chemistry; Calmodulin - genetics; Calmodulin - metabolism; Cell Line; Dopamine - metabolism; Fluorescence Resonance Energy Transfer - methods; Humans; Male; MAP Kinase Signaling System - physiology; Mechanisms of Signal Transduction; Molecular Sequence Data; Multiprotein Complexes; Protein Multimerization; Protein Structure, Tertiary; Proteins; Proteomics - methods; Proteïnes; Rats; Rats, Sprague-Dawley; Receptor, Adenosine A2A - chemistry; Receptor, Adenosine A2A - genetics; Receptor, Adenosine A2A - metabolism; Receptors, Dopamine D2 - chemistry; Receptors, Dopamine D2 - genetics; Receptors, Dopamine D2 - metabolism; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M109.034231

The Ca2+-binding protein calmodulin (CaM) has been shown to bind directly to cytoplasmic domains of some G protein-coupled receptors, including the dopamine D2 receptor. CaM binds to the N-terminal portion of the long third intracellular loop of the D2 receptor, within an Arg-rich epitope that is also involved in the binding to Gi/o proteins and to the adenosine A2A receptor, with the formation of A2A-D2 receptor heteromers. In the present work, by using proteomics and bioluminescence resonance energy transfer (BRET) techniques, we provide evidence for the binding of CaM to the A2A receptor. By using BRET and sequential resonance energy transfer techniques, evidence was obtained for CaM-A2A-D2 receptor oligomerization. BRET competition experiments indicated that, in the A2A-D2 receptor heteromer, CaM binds preferentially to a proximal C terminus epitope of the A2A receptor. Furthermore, Ca2+ was found to induce conformational changes in the CaM-A2A-D2 receptor oligomer and to selectively modulate A2A and D2 receptor-mediated MAPK signaling in the A2A-D2 receptor heteromer. These results may have implications for basal ganglia disorders, since A2A-D2 receptor heteromers are being considered as a target for anti-parkinsonian agents.