The stability of the G protein-coupled receptor-beta-arrestin interaction determines the mechanism and functional consequence of ERK activation.
By binding to agonist-activated G protein-coupled receptors (GPCRs), beta-arrestins mediate homologous receptor desensitization and endocytosis via clathrin-coated pits. Recent data suggest that beta-arrestins also contribute to GPCR signaling by acting as scaffolds for components of the ERK mitogen-activated protein kinase cascade. Because of these dual functions, we hypothesized that the stability of the receptor-beta-arrestin interaction might affect the mechanism and functional consequences of GPCR-stimulated ERK activation. In transfected COS-7 cells, we found that angiotensin AT1a and vasopressin V2 receptors, which form stable receptor-beta-arrestin complexes, activated a beta-arrestin-bound pool of ERK2 more efficiently than alpha 1b and beta2 adrenergic receptors, which form transient receptor-beta-arrestin complexes. We next studied chimeric receptors in which the pattern of beta-arrestin binding was reversed by exchanging the C-terminal tails of the beta2 and V2 receptors. The ability of the V2 beta 2 and beta 2V2 chimeras to activate beta-arrestin-bound ERK2 corresponded to the pattern of beta-arrestin binding, suggesting that the stability of the receptor-beta-arrestin complex determined the mechanism of ERK2 activation. Analysis of covalently cross-linked detergent lysates and cellular fractionation revealed that wild type V2 receptors generated a larger pool of cytosolic phospho-ERK1/2 and less nuclear phospho-ERK1/2 than the chimeric V2 beta 2 receptor, consistent with the cytosolic retention of beta-arrestin-bound ERK. In stably transfected HEK-293 cells, the V2 beta 2 receptor increased ERK1/2-mediated, Elk-1-driven transcription of a luciferase reporter to a greater extent than the wild type V2 receptor. Furthermore, the V2 beta 2, but not the V2 receptor, was capable of eliciting a mitogenic response. These data suggest that the C-terminal tail of a GPCR, by determining the stability of the receptor-beta-arrestin complex, controls the extent of beta-arrestin-bound ERK activation, and influences both the subcellular localization of activated ERK and the physiologic consequences of ERK activation.
Tohgo
Akira
A
Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
Choy
Eric W
EW
Gesty-Palmer
Diane
D
Pierce
Kristen L
KL
Laporte
Stephane
S
Oakley
Robert H
RH
Caron
Marc G
MG
Lefkowitz
Robert J
RJ
Luttrell
Louis M
LM
D000818:Animals; D019390:Arrestins / Q000235:genetics / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D004815:Epidermal Growth Factor / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism; D049452:Green Fluorescent Proteins; D007700:Kinetics; D008164:Luminescent Proteins / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008954:Models, Biological; D010766:Phosphorylation; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection; D014667:Vasopressins / Q000494:pharmacology; D000071557:beta-Arrestins
D019390:Arrestins; D008164:Luminescent Proteins; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D000071557:beta-Arrestins; D014667:Vasopressins; D049452:Green Fluorescent Proteins; D004815:Epidermal Growth Factor; D020928:Mitogen-Activated Protein Kinases; D019204:GTP-Binding Proteins