Premium
Novel roles for β‐arrestins in the regulation of pharmacological sequestration to predict agonist‐induced desensitization of dopamine D 3 receptors
Author(s) -
Min C,
Zheng M,
Zhang X,
Caron M G,
Kim K M
Publication year - 2013
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.12357
Subject(s) - g protein coupled receptor , receptor , homologous desensitization , internalization , microbiology and biotechnology , desensitization (medicine) , agonist , biology , g protein coupled receptor kinase , chemistry , pharmacology , biochemistry
Background and Purpose In addition to typical GPCR kinase ( GRK )‐/β‐arrestin‐dependent internalization, dopamine D 3 receptor employed an additional GRK ‐independent sequestration pathway. In this study, we investigated the molecular mechanism of this novel sequestration pathway. Experimental Approach Radioligand binding, flow cytometry and cell surface biotinylation assay were used to characterize trafficking properties of D 2 and D 3 receptors. Serine/threonine and N ‐linked glycosylation mutants of the D 3 receptor were utilized to locate receptor regions involved in pharmacological sequestration and desensitization. Various point mutants of the D 2 and D 3 receptors, whose sequestration and desensitization properties were altered, were combined with knockdown cells of GRK s or β‐arrestins to functionally correlate pharmacological sequestration and desensitization. Key Results The D 3 receptor, but not the D 2 receptor, showed characteristic trafficking behaviour in which receptors were shifted towards the more hydrophobic domains within the plasma membrane without translocation into other intracellular compartments. Among various amino acid residues tested, S145 / S146 , C147 and N12 /19 were involved in pharmacological sequestration and receptor desensitization. Both pharmacological sequestration and desensitization of D 3 receptor required β‐arrestins, and functional relationship was observed between two processes when it was tested for D 3 receptor variants and agonists. Conclusions and Implications Pharmacological sequestration of D 3 receptor accompanies movement of cell surface receptors into a more hydrophobic fraction within the plasma membrane and renders D 3 receptor inaccessible to hydrophilic ligands. Pharmacological sequestration is correlated with desensitization of the D 3 receptor in a G βγ‐ and β‐arrestin‐dependent manner. This study provides new insights into molecular mechanism governing GPCR trafficking and desensitization.