RGD Reference Report - Phosphorylation of a carboxyl-terminal serine within the kappa-opioid receptor produces desensitization and internalization. - Rat Genome Database

Send us a Message



Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   
Pathways

Phosphorylation of a carboxyl-terminal serine within the kappa-opioid receptor produces desensitization and internalization.

Authors: McLaughlin, JP  Xu, M  Mackie, K  Chavkin, C 
Citation: McLaughlin JP, etal., J Biol Chem. 2003 Sep 5;278(36):34631-40. Epub 2003 Jun 18.
RGD ID: 9831413
Pubmed: PMID:12815037   (View Abstract at PubMed)
DOI: DOI:10.1074/jbc.M304022200   (Journal Full-text)

G-protein receptor kinase and beta-arrestin mediated desensitization of the rat kappa-opioid receptor (KOR) was previously shown using Xenopus oocyte expression to require serine 369 within the C terminus of KOR. To define the effects of phosphorylation of this residue in desensitization and internalization processes in mammalian expression systems, wild-type KOR-green fluorescent protein (KOR-GFP) and KOR(S369A)-GFP were stably expressed in AtT-20 and HEK293 cells. Using whole-cell patch clamp recording in transfected AtT-20 cells, agonist activation of either kappa receptor form produced equivalent activation of the intrinsic G-protein-gated inwardly rectifying potassium channel. Incubation for 60 min with the kappa agonist U50,488 (100 nm) desensitized the response in cells expressing wild-type KOR-GFP by 86% but had no effect on KOR(S369A)-GFP-expressing cells. Phosphorylation of serine 369 was detected using a phosphospecific antibody (KOR-P) able to distinguish the phosphorylated form of the receptor. The agonist-induced increase in KOR-P labeling was dose-dependent, blocked by co-treatment with the kappa antagonist norbinaltorphimine, and prevented by co-expression of the dominant negative form of the G-protein receptor kinase, GRK2(K220R). In contrast, agonist-induced increase in KOR-P labeling was not evident in KOR(S369A) expressing cells. Prolonged activation resulted in receptor internalization that was also blocked by KOR(S369A) substitution, but interestingly, KOR-P labeling was evident at lower agonist concentrations than required to induce internalization. Following the removal of agonist, receptor dephosphorylation detected by loss of KOR-P labeling was complete within 60 min, could be blocked by okadaic acid, and was not blocked by sucrose inhibition of receptor internalization. These results demonstrate that GRK-mediated phosphorylation of serine 369 mediates rat KOR desensitization and internalization.



Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Oprk1Ratpositive regulation of potassium ion transmembrane transport  IDA  RGD 

Objects Annotated

Genes (Rattus norvegicus)
Oprk1  (opioid receptor, kappa 1)


Additional Information