title: Function of non-visual arrestins in signaling and endocytosis of the gastrin-releasing peptide receptor (GRP receptor).
abstract: Little is known about the role of arrestins in gastrointestinal hormone/neurotransmitter receptor endocytosis. With other G protein-coupled receptors, arrestins induce G protein-uncoupling and receptor endocytosis. In this study, we used arrestin wild-type and dominant-negative mutant constructs to analyze the arrestin dependence of endocytosis and desensitization of the gastrin-releasing peptide receptor (GRP-R). Co-expression of the GRP-R with wild-type arrestin2 and arrestin3 increased not only GRP-R endocytosis but also GRP-R desensitization in arrestin-overexpressing cells. Co-expression of the dominant-negative mutants V53D-arrestin2 or V54D-arrestin3 reduced GRP-R endocytosis. Notably, different trafficking routes for agonist-activated GRP-R-arrestin2 and GRP-R-arrestin3 complexes were found. Arrestin3 internalizes with GRP-R to intracellular vesicles, arrestin2 splits from the GRP-R and localizes to the cell membrane. Also, the recycling pathway of the GRP-R was different if co-expressed with arrestin2 or arrestin3. Using different GRP-R mutants, the C-terminus and the 2nd intracellular loop of the GRP-R were found to be important for the GRP-R-arrestin interaction and for the difference in GRP receptor trafficking with the two arrestin subtypes. Our results show that both non-visual arrestins play an important role in GRP-R internalization and desensitization.
authors.affiliation: Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA. michael.schumann@charite.de
authors.forename: Michael
authors.initials: M
authors.lastname: Schumann
authors.forename: Tomoo
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Mantey
authors.forename: Brian
authors.initials: B
authors.lastname: Howell
authors.forename: Robert T
authors.initials: RT
authors.lastname: Jensen
mesh_terms: D000818:Animals; D019390:Arrestins / Q000378:metabolism*; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D004705:Endocytosis; D006801:Humans; D051379:Mice; D021381:Protein Transport; D018004:Receptors, Bombesin / Q000378:metabolism*; D015398:Signal Transduction; D041701:Swiss 3T3 Cells; D000071557:beta-Arrestins
chemical_list: D019390:Arrestins; D018004:Receptors, Bombesin; C082333:arrestin3; D000071557:beta-Arrestins