title: Regulation of transport of the dopamine D1 receptor by a new membrane-associated ER protein.
abstract: Many structural determinants for G protein-coupled receptor (GPCR) functions have been defined, but little is known concerning the regulation of their transport from the endoplasmic reticulum (ER) to the cell surface. Here we show that a carboxy-terminal hydrophobic motif, FxxxFxxxF, which is highly conserved among GPCRs, functions independently as an ER-export signal for the dopamine D1 receptor. A newly identified ER-membrane-associated protein, DRiP78, binds to this motif. Overexpression or sequestration of DRiP78 leads to retention of D1 receptors in the ER, reduced ligand binding, and a slowdown in the kinetics of receptor glycosylation. Our results indicate that DRiP78 may regulate the transport of a GPCR by binding to a specific ER-export signal.
authors.affiliation: Department of Pharmacology, University of California, Irvine, California 92697, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Bermak
authors.forename: M
authors.initials: M
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Bullock
authors.forename: Q Y
authors.initials: QY
authors.lastname: Zhou
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D016827:CD8 Antigens / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008164:Luminescent Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000378:metabolism; D017447:Receptors, Dopamine D1 / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D020798:Two-Hybrid System Techniques
chemical_list: D016827:CD8 Antigens; D008024:Ligands; D008164:Luminescent Proteins; D011956:Receptors, Cell Surface; D017447:Receptors, Dopamine D1; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D000242:Cyclic AMP