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Dimerization of G-protein coupled receptors

review by Gether (2000):

- homodimers reported for (for refs. see Gether (2000) review):

    beta2-adrenergic receptor

    delta-opioid receptor

    dopamine D1,D2 and D3 receptors

    chemokine receptors CCR2b, CCR4, CCR5

    extracellular calcium-sensing receptor

    metabotropic glutamate receptor 5 (ref. Romano, C., W.L. Yang, and K.L. O'Malley, Metabotropic glutamate receptor 5 is a disulfide-linked dimer. J Biol Chem, 1996. 271(45): p. 28612-6)

- functional receptor dimers can be formed by coexpression of two non-functional chimeras constructed between alpha2c-adrenergic and M3-muscarinic receptor

- in beta2-adrenergic receptor, a peptide corresponding to TM VI inhibits dimer formation and dissociates dimers in dopamine D2 receptor

- in delta-opioid receptor, dimerization can be eliminated by deletion of 15 aa from the C-terminus

- in metabotropic glutamate receptors and the extracellular calcium sensing receptor dimerization is dependent on intermolecular disulfide bonds between cysteines in the N-term (ref: Romano, C., W.L. Yang, and K.L. O'Malley, Metabotropic glutamate receptor 5 is a disulfide-linked dimer. J Biol Chem, 1996. 271(45): p. 28612-6)

- agonist can stabilize dimers in beta2-adrenergic and chemokine receptors but agonist can decrease dimers in delta-opioid receptor    

- heterodimers between closely related subtypes:

    GABA B R1 is an immature glycoprotein that is retained inside cell with low affinity for agonists, when coexpressed with GABA B R2, fully functional and glycosylated expressed at the surface

- heterodimers between delta and kappa opioid receptors displays binding and functional properties distinct from those of either of the receptors

- there is a family of single TM proteins, RAMPS, receptor-activity-modifying proteins that complex with the calcitonin-receptor-like receptor CRLR