Dual RXR motifs regulate nerve growth factor-mediated intracellular retention of the delta opioid receptor

Mol Biol Cell. 2019 Mar 1;30(5):680-690. doi: 10.1091/mbc.E18-05-0292. Epub 2019 Jan 2.

Abstract

The delta opioid receptor (DOR), a physiologically relevant prototype for G protein-coupled receptors, is retained in intracellular compartments in neuronal cells. This retention is mediated by a nerve growth factor (NGF)-regulated checkpoint that delays the export of DOR from the trans-Golgi network. How DOR is selectively retained in the Golgi, in the midst of dynamic membrane transport and cargo export, is a fundamental unanswered question. Here we address this by investigating sequence elements on DOR that regulate DOR surface delivery, focusing on the C-terminal tail of DOR that is sufficient for NGF-mediated regulation. By systematic mutational analysis, we define conserved dual bi-arginine (RXR) motifs that are required for NGF- and phosphoinositide-regulated DOR export from intracellular compartments in neuroendocrine cells. These motifs were required to bind the coatomer protein I (COPI) complex, a vesicle coat complex that mediates primarily retrograde cargo traffic in the Golgi. Our results suggest that interactions of DOR with COPI, via atypical COPI motifs on the C-terminal tail, retain DOR in the Golgi. These interactions could provide a point of regulation of DOR export and delivery by extracellular signaling pathways.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Arginine / metabolism
  • COP-Coated Vesicles / metabolism
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cytoplasm / metabolism
  • Golgi Apparatus / drug effects
  • Golgi Apparatus / metabolism
  • Intracellular Space / drug effects*
  • Intracellular Space / metabolism*
  • Nerve Growth Factor / pharmacology*
  • PC12 Cells
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Binding / drug effects
  • Protein Domains
  • Rats
  • Receptors, Opioid, delta / chemistry
  • Receptors, Opioid, delta / metabolism*
  • Sequence Deletion
  • Structure-Activity Relationship

Substances

  • Phosphoinositide-3 Kinase Inhibitors
  • Receptors, Opioid, delta
  • Nerve Growth Factor
  • Arginine