C-terminal di-leucine motif of dopamine D₁ receptor plays an important role in its plasma membrane trafficking

PLoS One. 2011;6(12):e29204. doi: 10.1371/journal.pone.0029204. Epub 2011 Dec 19.

Abstract

The dopamine D₁ receptor (D₁R), a G protein-coupled receptor, plays a critical role in regulating blood pressure through its actions on renal hemodynamics and epithelial ion transport, which are highly linked to its intracellular trafficking. In this study, we generated a series of C-terminal mutants of D₁R that were tagged with or without enhanced yellow fluorescent protein, and analyzed the consequences of these mutants on the plasma membrane trafficking of D₁R and cyclic AMP response to D₁R stimulation. D₁R with mutations within the endocytic recycling signal (amino acid residues 360-382) continued to be functional, albeit decreased relative to wild-type D₁R. Mutation of the palmitoylation site (347C>S) of D₁R did not impair its trafficking to the plasma membrane, but abolished its ability to increase cyclic AMP accumulation. In contrast, replacement of di-leucines (344-345L>A) by alanines resulted in the retention of D₁R in the early endosome, decreased its glycosylation, and prevented its targeting to the plasma membrane. Our studies suggest that di-L motif at the C-terminus of D₁R is critical for the glycosylation and cell surface targeting of D₁R.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Cell Membrane / metabolism*
  • Cyclic AMP / metabolism
  • Endoplasmic Reticulum / metabolism
  • Endosomes / metabolism
  • Glycosylation
  • HEK293 Cells
  • Humans
  • Leucine*
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Mutation
  • Protein Transport
  • Receptors, Dopamine D1 / agonists
  • Receptors, Dopamine D1 / chemistry*
  • Receptors, Dopamine D1 / genetics
  • Receptors, Dopamine D1 / metabolism*

Substances

  • Receptors, Dopamine D1
  • Cyclic AMP
  • Leucine