Format

Send to

Choose Destination
Sci Signal. 2018 Jul 17;11(539). pii: eaas9609. doi: 10.1126/scisignal.aas9609.

Multisite phosphorylation is required for sustained interaction with GRKs and arrestins during rapid μ-opioid receptor desensitization.

Author information

1
Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany.
2
Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052, Australia.
3
Discipline of Pharmacology, University of Sydney, New South Wales 2006, Australia.
4
Department of Pharmacology and Toxicology, Philipps-University Marburg, D-35043 Marburg, Germany.
5
Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany. stefan.schulz@med.uni-jena.de meri.canals@monash.edu.
6
Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052, Australia. stefan.schulz@med.uni-jena.de meri.canals@monash.edu.

Abstract

G protein receptor kinases (GRKs) and β-arrestins are key regulators of μ-opioid receptor (MOR) signaling and trafficking. We have previously shown that high-efficacy opioids such as DAMGO stimulate a GRK2/3-mediated multisite phosphorylation of conserved C-terminal tail serine and threonine residues, which facilitates internalization of the receptor. In contrast, morphine-induced phosphorylation of MOR is limited to Ser375 and is not sufficient to drive substantial receptor internalization. We report how specific multisite phosphorylation controlled the dynamics of GRK and β-arrestin interactions with MOR and show how such phosphorylation mediated receptor desensitization. We showed that GRK2/3 was recruited more quickly than was β-arrestin to a DAMGO-activated MOR. β-Arrestin recruitment required GRK2 activity and MOR phosphorylation, but GRK recruitment also depended on the phosphorylation sites in the C-terminal tail, specifically four serine and threonine residues within the 370TREHPSTANT379 motif. Our results also suggested that other residues outside this motif participated in the initial and transient recruitment of GRK and β-arrestins. We identified two components of high-efficacy agonist desensitization of MOR: a sustained component, which required GRK2-mediated phosphorylation and a potential soluble factor, and a rapid component, which was likely mediated by GRK2 but independent of receptor phosphorylation. Elucidating these complex receptor-effector interactions represents an important step toward a mechanistic understanding of MOR desensitization that leads to the development of tolerance and dependence.

PMID:
30018083
DOI:
10.1126/scisignal.aas9609

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center