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COUPLING OF A G‐PROTEIN COUPLED RECEPTOR TO THE AGS3‐Galphai SIGNALING COMPLEX
Author(s) -
Oner Sukru Sadik,
An Ningfei,
Vural Ali,
Breton Billy,
Bouvier Michel,
Blumer Joe B.,
Lanier Stephen M.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.587.7
Subject(s) - heterotrimeric g protein , g protein coupled receptor , microbiology and biotechnology , g protein , receptor , chemistry , signal transduction , g beta gamma complex , yellow fluorescent protein , g protein coupled receptor kinase , biophysics , biology , biochemistry , gene
AGS3 and related entities serve as alternative binding partners for Gαi independent of the classical heterotrimer Gαβγ and this interaction is mediated by a 20–25 amino acid motif termed the G‐protein regulatory (GPR). Such a signaling module may function in the context of signal processing through G‐protein coupled receptors or actually regulate intracellular events independent of the classical receptor ‐ heterotrimeric G‐protein – effector model. We report the regulation of the GPR‐Gαi signaling module by a cell surface receptor using bioluminescence resonance energy transfer (BRET). AGS3‐ Renilla luciferase (Rluc), and Gαi1‐yellow fluorescent protein (YFP) exhibited robust, specific BRET. AGS3‐Rluc ‐ Gαil‐YFP BRET was inhibited by activation of the α 2 ‐adrenergic receptor (α 2 ‐AR), a typical G‐protein coupled receptor that couples to the Gαi/Gαo class of heterotrimeric G‐proteins. The AGS3‐Gαi complex is in close proximity to the receptor as Gαi‐dependent and agonist‐sensitive BRET was observed between AGS3‐Rluc and the α 2 ‐AR‐Venus. AGS3‐Gαi appears to be anchored within a receptor signaling complex at the membrane and the biophysical organization of this complex is stabilized or destabilized by specific conformations of the receptor.