A Dominant Negative Mutant of the G Protein-Coupled Receptor Kinase 2 Selectively Attenuates Adenosine A2 Receptor Desensitization

• Published in: Molecular pharmacology Vol. 51; no. 6; pp. 991 - 998
• Main Authors: Mundell, Stuart J., Benovic, Jeffrey L., Kelly, Eamonn
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.06.1997; American Society for Pharmacology and Experimental Therapeutics
• Subjects: Adenosine - analogs & derivatives; Adenosine - pharmacology; Adenosine-5'-(N-ethylcarboxamide); Adenylyl Cyclases - metabolism; Adenylyl Cyclases - physiology; Animals; beta-Adrenergic Receptor Kinases; Cyclic AMP-Dependent Protein Kinases - genetics; Cyclic AMP-Dependent Protein Kinases - physiology; G-Protein-Coupled Receptor Kinase 2; G-Protein-Coupled Receptor Kinase 3; Glioma; Hybrid Cells; Mice; Mutation; Neuroblastoma; Purinergic P1 Receptor Agonists; Rats; Receptors, Prostaglandin - physiology; Receptors, Purinergic P1 - physiology; Secretin - physiology; Sensitivity and Specificity; Tumor Cells, Cultured; DNM GRK2; GRK; NECA; TE; CSC; SDS; HEPES; ECL
• ISSN: 0026-895X; 1521-0111
• DOI: 10.1124/mol.51.6.991

G protein-coupled receptor kinases (GRKs) are thought to be important in mediating the agonist-induced phosphorylation and consequent desensitization of G protein-coupled receptor responses. NG108–15 mouse neuroblastoma X rat glioma cells express a wide range of G protein-coupled receptors and significant levels of GRK2. Therefore, to determine the role of GRK2 in agonist-induced desensitization of various Gs-coupled receptors in NG108–15 cells, we stably transfected cells with a dominant negative mutant GRK2 construct (Lys220Arg). In homogenates prepared from cells overexpressing the dominant negative mutant GRK2, the acute stimulation of adenylyl cyclase by various receptor and nonreceptor agonists was the same as in control cells stably transfected with plasmid only. NG108–15 cells express both A2a and A2b adenosine receptors, which mediate activation of adenylyl cyclase, with both of these responses being subject to agonist-induced desensitization with at1/2 of 15–20 min. In dominant negative mutant GRK2 cells, the rates of desensitization of A2a and A2b receptor-stimulated adenylyl cyclase were markedly slower than in plasmid transfected controls, with the latter being similar to wild-type cells. After a 20-min treatment with an adenosine agonist, the desensitization of A2a and A2breceptor-stimulated adenylyl cyclase in dominant negative mutant GRK2 cells was less than half that seen in plasmid transfected control cells. On the other hand, the agonist-induced desensitization of secretin and IP-prostanoid receptor-stimulated adenylyl cyclase was the same in dominant negative mutant GRK2 cells as in plasmid transfected control cells. These results indicate that in intact cells, GRK2 may mediate the desensitization of adenosine A2 receptors. Furthermore, there seems to be selectivity of GRK2 action between Gs-coupled receptors because the agonist-induced desensitization of secretin and IP-prostanoid receptor-stimulated adenylyl cyclase was not affected by dominant negative mutant GRK2 overexpression.