Allosteric communication between protomers of dopamine class A GPCR dimers modulates activation


A major obstacle to understanding the functional importance of dimerization between class A G protein–coupled receptors (GPCRs) has been the methodological limitation in achieving control of the identity of the components comprising the signaling unit. We have developed a functional complementation assay that enables such control, and we demonstrate it here for the human dopamine D2 receptor. The minimal signaling unit, two receptors and a single G protein, is maximally activated by agonist binding to a single protomer, which suggests an asymmetrical activated dimer. Inverse agonist binding to the second protomer enhances signaling, whereas agonist binding to the second protomer blunts signaling. Ligand-independent constitutive activation of the second protomer also inhibits signaling. Thus, GPCR dimer function can be modulated by the activity state of the second protomer, which for a heterodimer may be altered in pathological states. Our new methodology also makes possible the characterization of signaling from a defined heterodimer unit.

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Figure 1: Functional complementation of two 'nonfunctional receptors'.
Figure 2: Characterization of D2R mutants.
Figure 3: Asymmetric contributions of the protomers to signaling.
Figure 4: The second protomer allosterically modulates signaling.
Figure 5: Computational model of the complex between the rhodopsin dimer and heterotrimeric Gt.
Figure 6: Cartoon of different D2R dimer activation states, with activation data for these states, from the perspective of agonist-mediated activation of protomer A.


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We thank C. Galás for discussion and comments on the manuscript. Plasmids encoding apo-aequorin were a gift from V. Dupriez (Euroscreen). This work was supported in part by US National Institutes of Health grants DA022413 and MH054137 (to J.A.J.) and DA012923 (to H.W.), by the Lieber Center for Schizophrenia Research and Treatment, and by a European Molecular Biology Organization long-term fellowship (to E.U.). Computational resources of the David A. Cofrin Center for Biomedical Information (Institute for Computational Biomedicine, Weill Cornell Medical College of Cornell University) are gratefully acknowledged.

Author information




Y.H. created all the mutant constructs and cell lines, helped to design the experiments, carried out the experimental assays and analyzed the results. I.S.M. performed the computational analysis. E.U., H.W. and J.A.J. helped to design experiments and interpret results. All the authors participated in the writing and editing of the manuscript.

Corresponding author

Correspondence to Jonathan A Javitch.

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Supplementary Figures 1–10, Supplementary Tables 1 and 2, and Supplementary Methods (PDF 1033 kb)

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Han, Y., Moreira, I., Urizar, E. et al. Allosteric communication between protomers of dopamine class A GPCR dimers modulates activation. Nat Chem Biol 5, 688–695 (2009).

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