Efficient G protein coupling is not required for agonist-mediated internalization and membrane reorganization of the adenosine A3 receptor

摘要: Organization of G protein-coupled receptors at the plasma membrane has been focus much recent attention. Advanced microscopy techniques have shown that these can be localized to discrete microdomains and reorganization upon ligand activation is crucial in orchestrating their signaling. Here, we compared organization downstream signaling a mutant (R108A, R3.50A) adenosine A3 receptor (A3 AR) wild-type receptor. Fluorescence Correlation Spectroscopy (FCS) studies with fluorescent agonist (ABEA-X-BY630) demonstrated both bind high affinity but subsequent assays R108A mutation abolished agonist-mediated inhibition cAMP production ERK phosphorylation. In further FCS studies, AR underwent similar agonist-induced increases density molecular brightness which were accompanied by decrease diffusion after treatment. Using bimolecular fluorescence complementation, experiments showed retained ability recruit β-arrestin receptor/arrestin complexes displayed observed receptors. These data demonstrate effective protein not prerequisite for agonist-stimulated recruitment AR.