beta-Arrestin 2 expression determines the transcriptional response to lysophosphatidic acid stimulation in murine embryo fibroblasts.
G protein-coupled receptors often employ novel signaling mechanisms, such as transactivation of epidermal growth factor (EGF) receptors or G protein-independent signals transmitted by beta-arrestins, to control the activity of extracellular signal-regulated kinases 1 and 2 (ERK1/2). In this study we investigated the role of beta-arrestins in lysophosphatidic acid (LPA) receptor-stimulated ERK1/2 activation using fibroblast lines derived from wild type, beta-arrestin 1, beta-arrestin 2, and beta-arrestin 1/2 knock-out mice. LPA stimulation produced robust ERK1/2 phosphorylation in all four backgrounds. In cells lacking beta-arrestin 2, >80% of LPA-stimulated ERK1/2 phosphorylation was mediated by transactivated EGF receptors. In contrast, ERK1/2 activation in cells expressing beta-arrestin 2 was predominantly EGF receptor-independent. Introducing FLAG epitope-tagged beta-arrestin 2 into the beta-arrestin 1/2 null background restored EGF receptor-independent ERK1/2 activation, indicating that beta-arrestin 2 expression confers ERK1/2 activation via a distinct mechanism. To determine the contributions of beta-arrestin 2, transactivated EGF receptors, and ERK1/2 to LPA-stimulated transcriptional responses, we employed gene expression arrays containing cDNA markers for G protein-coupled receptor-mediated signaling. In the beta-arrestin 1/2 null background, 1 h of exposure to LPA significantly increased transcription of seven marker genes. Six of these responses were EGF receptor-dependent, and two required ERK1/2 activation. In beta-arrestin 2 expressing cells, three of the seven LPA-stimulated transcriptional responses observed in the beta-arrestin 1/2 null background were lost. The four residual responses were independent of EGF receptor transactivation, but all were ERK1/2-dependent. These data indicate that beta-arrestin 2 functions both to attenuate EGF receptor transactivation-dependent signaling and to promote a distinct subset of ERK1/2-mediated responses to LPA receptor activation.
Gesty-Palmer
Diane
D
Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
El Shewy
Hesham
H
Kohout
Trudy A
TA
Luttrell
Louis M
LM
D000818:Animals; D019390:Arrestins / Q000096:biosynthesis* / Q000378:metabolism; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000378:metabolism; D000939:Epitopes / Q000737:chemistry; D066246:ErbB Receptors / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D008246:Lysophospholipids / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D008954:Models, Biological; D010766:Phosphorylation; D011799:Quinazolines; D012313:RNA / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D020032:Tyrphostins / Q000494:pharmacology; D000071559:beta-Arrestin 1; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins; D018631:ras Proteins / Q000378:metabolism
C000605253:ARRB1 protein, human; C000605254:ARRB2 protein, human; C000605255:Arrb1 protein, mouse; C000605258:Arrb2 protein, mouse; D019390:Arrestins; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D000939:Epitopes; D005419:Flavonoids; D008246:Lysophospholipids; D011799:Quinazolines; D020032:Tyrphostins; D000071559:beta-Arrestin 1; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins; C101044:RTKI cpd; D004815:Epidermal Growth Factor; D012313:RNA; D066246:ErbB Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D018631:ras Proteins; C032881:lysophosphatidic acid; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one