title: Agonist-dependent desensitization of the kappa opioid receptor by G protein receptor kinase and beta-arrestin.
abstract: We used the Xenopus oocyte expression system to examine the regulation of rat kappa opioid receptor (rKOR) function by G protein receptor kinases (GRKs). kappa agonists increased the conductance of G protein-activated inwardly rectifying potassium channels in oocytes co-expressing KOR with Kir3.1 and Kir3.4. In the absence of added GRK and beta-arrestin 2, desensitization of the kappa agonist-induced potassium current was modest. Co-expression of either GRK3 or GRK5 along with beta-arrestin 2 significantly increased the rate of desensitization, whereas addition of either beta-arrestin 2, GRK3, or GRK5 alone had no effect on the KOR desensitization rate. The desensitization was homologous as co-expressed delta opioid receptor-evoked responses were not affected by KOR desensitization. The rate of GRK3/beta-arrestin 2-dependent desensitization was reduced by truncation of the C-terminal 26 amino acids, KOR(Q355Delta). In contrast, substitution of Ala for Ser within the third intracellular loop [KOR(S255A,S260A, S262A)] did not reduce the desensitization rate. Within the C-terminal region, KOR(S369A) substitution significantly attenuated desensitization, whereas the KOR(T363A) and KOR(S356A,T357A) point mutations did not. These results suggest that co-expression of GRK3 or GRK5 and beta-arrestin 2 produced homologous, agonist-induced desensitization of the kappa opioid receptor by a mechanism requiring the phosphorylation of the serine 369 of rKOR.
authors.affiliation: Neurobiology Program, University of Washington, Seattle, Washington 98195-7280, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Appleyard
authors.forename: J
authors.initials: J
authors.lastname: Celver
authors.forename: V
authors.initials: V
authors.lastname: Pineda
authors.forename: A
authors.initials: A
authors.lastname: Kovoor
authors.forename: G A
authors.initials: GA
authors.lastname: Wayman
authors.forename: C
authors.initials: C
authors.lastname: Chavkin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019390:Arrestins / Q000502:physiology*; D044482:Benzeneacetamides; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000494:pharmacology; D005260:Female; D054770:G-Protein-Coupled Receptor Kinase 3; D008969:Molecular Sequence Data; D017346:Protein Serine-Threonine Kinases; D011759:Pyrrolidines / Q000494:pharmacology; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology*; D017473:Receptors, Opioid, kappa / Q000819:agonists / Q000737:chemistry / Q000502:physiology*; D013329:Structure-Activity Relationship; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins
chemical_list: C000605257:Arrb2 protein, rat; D019390:Arrestins; D044482:Benzeneacetamides; D004745:Enkephalins; D011759:Pyrrolidines; D017473:Receptors, Opioid, kappa; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins; D020881:Enkephalin, D-Penicillamine (2,5)-; D020794:Receptor Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D054770:G-Protein-Coupled Receptor Kinase 3; C517851:Grk3 protein, rat; C045444:U 69593