title: RGS2 and RGS4 proteins: New modulators of the κ-opioid receptor signaling.
abstract: Previous studies have shown that RGS4 associates with the C-termini of μ- and δ-opioid receptors in living cells and plays a key role in Gi/Go protein coupling selectivity and signalling of these receptors [12,20]. To deduce whether similar effects also occur for the κ-opioid receptor (κ-ΟR) and define the ability of members of the Regulators of G protein Signaling (RGS) of the B/R4 subfamily to interact with κ-ΟR subdomains we generated glutathione S-transferase fusion peptides encompassing the carboxyl-termini of κ-OR (κ-CT). Results from pull down experiments indicated that RGS2 and RGS4 directly interact within different domains of the κ-CT. Co-precipitation studies in living cells indicated that RGS2 and RGS4 associate with κ-ΟR constitutively and upon receptor activation and confer selectivity for coupling with a specific subset of G proteins. Expression of both members, RGS2 and/or RGS4, in 293F cells attenuated κ-agonist mediated-adenylyl cyclase inhibition and extracellular signal regulated kinase (ERK1,2) phosphorylation with a different amplitude in their modulatory effect in κ-ΟR signaling. Our findings demonstrate that RGS2 and RGS4 are new interacting partners that play key roles in G protein coupling to negatively regulate κ-ΟR signaling.
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research "Demokritos", Athens, Greece.
authors.forename: Maria-Pagona
authors.initials: MP
authors.lastname: Papakonstantinou
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research "Demokritos", Athens, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Karoussiotis
authors.affiliation: Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research "Demokritos", Athens, Greece. Electronic address: iro@bio.demokritos.gr.
authors.forename: Zafiroula
authors.initials: Z
authors.lastname: Georgoussi
mesh_terms: D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D004705:Endocytosis; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D044385:GTP-Binding Protein alpha Subunits / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008954:Models, Biological; D010766:Phosphorylation; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism; D020710:RGS Proteins / Q000378:metabolism*; D017465:Receptors, Opioid, delta / Q000378:metabolism; D017473:Receptors, Opioid, kappa / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D044385:GTP-Binding Protein alpha Subunits; D021122:Protein Subunits; D020710:RGS Proteins; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; C105345:Rgs2 protein, mouse; C098799:RGS4 protein; D048049:Extracellular Signal-Regulated MAP Kinases; D000262:Adenylyl Cyclases
keywords: G proteins; Internalization; Receptor–protein interactions; Regulators of G protein signaling; Signaling complex; κ-opioid receptor