Open AccessA dileucine motif in the C terminus of the β 2 -adrenergic receptor is involved in receptor internalization
Author(s) -
Ane M. Gabilondo,
Jutta Hegler,
Cornelius Krasel,
Valérie BoivinJahns,
Lutz Hein,
Martin J. Lohse
Publication year - 1997
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.94.23.12285
Subject(s) - internalization , receptor , microbiology and biotechnology , g protein coupled receptor , enzyme linked receptor , 5 ht5a receptor , biology , hek 293 cells , agonist , endosome , biochemistry
The cytoplasmic C terminus of the β2 -adrenergic receptor and many other G protein-coupled receptors contains a dileucine sequence that has been implicated in endosome/lysosome targeting of diverse proteins. In the present study, we provide evidence for an essential role of this motif in the agonist-induced internalization of the β2 -adrenergic receptor. Mutation of Leu-339 and/or Leu-340 to Ala caused little changes in surface expression, ligand binding, G protein coupling, and signaling to adenylyl cyclase, when these receptors were transiently or stably expressed in CHO or HEK-293 cells. However, agonist-induced receptor internalization was markedly impaired in the L339,340 A double mutant and reduced in the two single mutants. This impairment in receptor internalization was seen by using various approaches to determine internalization: binding of hydrophobic vs. hydrophilic ligands, loss of surface β2 -adrenergic receptor immunoreactivity, and immunofluorescence microscopy. The selective effects of these mutations suggest that the C-terminal dileucine motif is involved in agonist-induced internalization of the β2 -adrenergic receptor.