Dopamine D1 and corticotrophin-releasing hormone type-2[alpha] receptors assemble into functionally interacting complexes in living cells

• Published in: British journal of pharmacology 2014-12, Vol.171 (24), p.5650
• Main Authors: Fuenzalida, J, Galaz, P, Araya, K A, Slater, P G, Blanco, E H, Campusano, J M, Ciruela, F, Gysling, K
• Format: Article
• Language: English
• Subjects: Dopamine; Rodents
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1111/bph.12868

Background and Purpose Dopamine and corticotrophin-releasing hormone (CRH; also known as corticotrophin-releasing factor) are key neurotransmitters in the interaction between stress and addiction. Repeated treatment with cocaine potentiates glutamatergic transmission in the rat basolateral amygdala/cortex pathway through a synergistic action of D1-like dopamine receptors and CRH type-2[alpha] receptors (CRF2[alpha] receptors). We hypothesized that this observed synergism could be instrumented by heteromers containing the dopamine D1 receptor and CRF2[alpha] receptor. Experimental Approach D1/CRF2[alpha] receptor heteromerization was demonstrated in HEK293T cells using co-immunoprecipitation, BRET and FRET assays, and by using the heteromer mobilization strategy. The ability of D1 receptors to signal through calcium, when singly expressed or co-expressed with CRF2[alpha] receptors, was evaluated by the calcium mobilization assay. Key Results D1/CRF2[alpha] receptor heteromers were observed in HEK293T cells. When singly expressed, D1 receptors were mostly located at the cell surface whereas CRF2[alpha] receptors accumulated intracellularly. Interestingly, co-expression of both receptors promoted D1 receptor intracellular and CRF2[alpha] receptor cell surface targeting. The heteromerization of D1/CRF2[alpha] receptors maintained the signalling through cAMP of both receptors but switched D1 receptor signalling properties, as the heteromeric D1 receptor was able to mobilize intracellular calcium upon stimulation with a D1 receptor agonist. Conclusions and Implications D1 and CRF2[alpha] receptors are capable of heterodimerization in living cells. D1/CRF2[alpha] receptor heteromerization might account, at least in part, for the complex physiological interactions established between dopamine and CRH in normal and pathological conditions such as addiction, representing a new potential pharmacological target.