C-terminal di-leucine motif of dopamine D₁ receptor plays an important role in its plasma membrane trafficking.
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.
Center for Molecular Physiology Research, Children's National Medical Center, Washington, D.C, United States of America. gygq@yahoo.com
Yan
Y
Guo
Pedro A
PA
Jose
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D006031:Glycosylation; D057809:HEK293 Cells; D006801:Humans; D007930:Leucine; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D021381:Protein Transport; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D017447:Receptors, Dopamine D1; D000242:Cyclic AMP; D007930:Leucine