N-linked Glycosylation on the N-terminus of the dopamine D2 and D3 receptors determines receptor association with specific microdomains in the plasma membrane

Biochim Biophys Acta. 2015 Jan;1853(1):41-51. doi: 10.1016/j.bbamcr.2014.09.024. Epub 2014 Oct 5.


Numerous G protein-coupled receptors (GPCRs) are glycosylated at extracellular regions. The regulatory roles of glycosylation on receptor function vary across receptor types. In this study, we used the dopamine D₂and D₃receptors as an experimental model to understand the underlying principles governing the functional roles of glycosylation. We used the pharmacological inhibitor, tunicamycin, to inhibit glycosylation, generated chimeric D₂and D₃receptors by swapping their respective N-termini, and produced the glycosylation site mutant D₂and D₃receptors to study the roles of glycosylation on receptor functions, including cell surface expression, signaling, and internalization through specific microdomains. Our results demonstrate that glycosylation on the N-terminus of the D₃ receptor is involved in the development of desensitization and proper cell surface expression. In addition, glycosylation on the N-terminus mediates the internalization of D₂and D₃receptors within the caveolae and clathrin-coated pit microdomains of the plasma membrane, respectively, by regulating receptor interactions with caveolin-1 and clathrin. In conclusion, this study shows for the first time that glycosylation on the N-terminus of GPCRs is involved in endocytic pathway selection through specific microdomains. These data suggest that changes in the cellular environment that influence posttranslational modification could be an important determinant of intracellular GPCR trafficking.

Keywords: MβCD; PNGaseF; Post-translational modification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Endocytosis
  • Glycosylation
  • HEK293 Cells
  • Humans
  • Membrane Microdomains / chemistry*
  • Molecular Sequence Data
  • Receptors, Dopamine D2 / chemistry*
  • Receptors, Dopamine D2 / metabolism
  • Receptors, Dopamine D3 / chemistry*
  • Receptors, Dopamine D3 / metabolism
  • Tunicamycin / pharmacology


  • DRD2 protein, human
  • DRD3 protein, human
  • Receptors, Dopamine D2
  • Receptors, Dopamine D3
  • Tunicamycin