title: The beta-arrestin pathway-selective type 1A angiotensin receptor (AT1A) agonist [Sar1,Ile4,Ile8]angiotensin II regulates a robust G protein-independent signaling network.
abstract: The angiotensin II peptide analog [Sar(1),Ile(4),Ile(8)]AngII (SII) is a biased AT(1A) receptor agonist that stimulates receptor phosphorylation, β-arrestin recruitment, receptor internalization, and β-arrestin-dependent ERK1/2 activation without activating heterotrimeric G-proteins. To determine the scope of G-protein-independent AT(1A) receptor signaling, we performed a gel-based phosphoproteomic analysis of AngII and SII-induced signaling in HEK cells stably expressing AT(1A) receptors. A total of 34 differentially phosphorylated proteins were detected, of which 16 were unique to SII and eight to AngII stimulation. MALDI-TOF/TOF mass fingerprinting was employed to identify 24 SII-sensitive phosphoprotein spots, of which three (two peptide inhibitors of protein phosphatase 2A (I1PP2A and I2PP2A) and prostaglandin E synthase 3 (PGES3)) were selected for validation and further study. We found that phosphorylation of I2PP2A was associated with rapid and transient inhibition of a β-arrestin 2-associated pool of protein phosphatase 2A, leading to activation of Akt and increased phosphorylation of glycogen synthase kinase 3β in an arrestin signalsome complex. SII-stimulated PGES3 phosphorylation coincided with an increase in β-arrestin 1-associated PGES3 and an arrestin-dependent increase in cyclooxygenase 1-dependent prostaglandin E(2) synthesis. These findings suggest that AT(1A) receptors regulate a robust G protein-independent signaling network that affects protein phosphorylation and autocrine/paracrine prostaglandin production and that these pathways can be selectively modulated by biased ligands that antagonize G protein activation.
authors.affiliation: Department of Medicine, Division of Endocrinology, Diabetes, and Medical Genetics, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Kendall
authors.forename: Erik G
authors.initials: EG
authors.lastname: Strungs
authors.forename: Saleh M
authors.initials: SM
authors.lastname: Rachidi
authors.forename: Mi-Hye
authors.initials: MH
authors.lastname: Lee
authors.forename: Hesham M
authors.initials: HM
authors.lastname: El-Shewy
authors.forename: Deirdre K
authors.initials: DK
authors.lastname: Luttrell
authors.forename: Michael G
authors.initials: MG
authors.lastname: Janech
authors.forename: Louis M
authors.initials: LM
authors.lastname: Luttrell
mesh_terms: D000804:Angiotensin II / Q000031:analogs & derivatives / Q000494:pharmacology*; D019390:Arrestins / Q000235:genetics / Q000378:metabolism; D051545:Cyclooxygenase 1 / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D015232:Dinoprostone / Q000096:biosynthesis / Q000235:genetics; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D057809:HEK293 Cells; D056488:Histone Chaperones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D054648:Protein Phosphatase 2 / Q000235:genetics / Q000378:metabolism; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D000071559:beta-Arrestin 1; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins
chemical_list: C000605253:ARRB1 protein, human; C000605254:ARRB2 protein, human; D019390:Arrestins; D004268:DNA-Binding Proteins; D056488:Histone Chaperones; D044140:Receptor, Angiotensin, Type 1; C513473:SET protein, human; D014157:Transcription Factors; D014662:Vasoconstrictor Agents; D000071559:beta-Arrestin 1; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins; D000804:Angiotensin II; D051545:Cyclooxygenase 1; C496511:PTGS1 protein, human; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D038362:Glycogen Synthase Kinase 3; D054648:Protein Phosphatase 2; D019204:GTP-Binding Proteins; D015232:Dinoprostone