Translocation of arrestin induced by human A(3) adenosine receptor ligands in an engineered cell line: comparison with G protein-dependent pathways.
Structurally diverse ligands were studied in A(3) adenosine receptor (AR)-mediated beta-arrestin translocation in engineered CHO cells. The agonist potency and efficacy were similar, although not identical, to their G protein signaling. However, differences have also been found. MRS542, MRS1760, and other adenosine derivatives, A(3)AR antagonists in cyclic AMP assays, were partial agonists in beta-arrestin translocation, indicating possible biased agonism. The xanthine 7-riboside DBXRM, a full agonist, was only partially efficacious in beta-arrestin translocation. DBXRM was shown to induce a lesser extent of desensitization compared with IB-MECA. In kinetic studies, MRS3558, a potent and selective A(3)AR agonist, induced beta-arrestin translocation significantly faster than IB-MECA and Cl-IB-MECA. Non-nucleoside antagonists showed similar inhibitory potencies as previously reported. PTX pretreatment completely abolished ERK1/2 activation, but not arrestin translocation. Thus, lead candidates for biased agonists at the A(3)AR have been identified with this arrestin-translocation assay, which promises to be an effective tool for ligand screening.
Gao
Zhan-Guo
ZG
Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 8A, Room B1A-19, Bethesda, MD, USA.
Jacobson
Kenneth A
KA
D058909:Adenosine A3 Receptor Agonists; D000818:Animals; D019393:Arrestin / Q000378:metabolism*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000502:physiology*; D021381:Protein Transport; D043684:Receptor, Adenosine A3 / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D013329:Structure-Activity Relationship
D058909:Adenosine A3 Receptor Agonists; D019393:Arrestin; D043684:Receptor, Adenosine A3; D000242:Cyclic AMP; D048049:Extracellular Signal-Regulated MAP Kinases; D019204:GTP-Binding Proteins