title: β-Arrestin-mediated Angiotensin II Signaling Controls the Activation of ARF6 Protein and Endocytosis in Migration of Vascular Smooth Muscle Cells.
abstract: Angiotensin II (Ang II) is a vasopressive hormone but is also a potent activator of cellular migration. We have previously shown that it can promote the activation of the GTPase ARF6 in a heterologous overexpressing system. The molecular mechanisms by which receptors control the activation of this small G protein remain, however, largely unknown. Furthermore, how ARF6 coordinates the activation of complex cellular responses needs to be further elucidated. In this study, we demonstrate that Ang II receptors engage β-arrestin, but not Gq, to mediate ARF6 activation in HEK 293 cells. To further confirm the key role of β-arrestin proteins, we overexpressed β-arrestin2-(1-320), a dominant negative mutant known to block receptor endocytosis. We show that expression of this truncated construct does not support the activation of the GTPase nor cell migration. Interestingly, β-arrestin2 can interact with the ARF guanine nucleotide exchange factor ARNO, although the C-terminally lacking mutant does not. We finally examined whether receptor endocytosis controlled ARF6 activation and cell migration. Although the clathrin inhibitor PitStop2 did not impact the ability of Ang II to activate ARF6, cell migration was markedly impaired. To further show that ARF activation regulates key signaling events leading to migration, we also examined MAPK activation. We demonstrate that this signaling axis is relevant in smooth muscle cells of the vasculature. Altogether, our findings show for the first time that Ang II receptor signaling to β-arrestin regulates ARF6 activation. These proteins together control receptor endocytosis and ultimately cell migration.
authors.affiliation: From the Department of Pharmacology, Faculty of Medicine, Université de Montréal, Montreal, Quebec H3C 3J7 and.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Charles
authors.affiliation: the Department of Medicine, Research Institute of McGill University Health Center, McGill University, Montreal, Quebec H4A 3J1, Canada.
authors.forename: Yoon
authors.initials: Y
authors.lastname: Namkung
authors.affiliation: From the Department of Pharmacology, Faculty of Medicine, Université de Montréal, Montreal, Quebec H3C 3J7 and.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Cotton
authors.affiliation: the Department of Medicine, Research Institute of McGill University Health Center, McGill University, Montreal, Quebec H4A 3J1, Canada.
authors.forename: Stéphane A
authors.initials: SA
authors.lastname: Laporte
authors.affiliation: From the Department of Pharmacology, Faculty of Medicine, Université de Montréal, Montreal, Quebec H3C 3J7 and audrey.claing@umontreal.ca.
authors.forename: Audrey
authors.initials: A
authors.lastname: Claing
mesh_terms: D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000235:genetics / Q000378:metabolism*; D000804:Angiotensin II / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D019390:Arrestins / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011945:Receptors, Angiotensin / Q000235:genetics / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology; D053778:Thiazolidines / Q000494:pharmacology; D000071557:beta-Arrestins
chemical_list: D000089982:ADP-Ribosylation Factor 6; D019390:Arrestins; D011945:Receptors, Angiotensin; D013449:Sulfonamides; D053778:Thiazolidines; D000071557:beta-Arrestins; C578512:pitstop 2; D000804:Angiotensin II; D048049:Extracellular Signal-Regulated MAP Kinases; D020727:ADP-Ribosylation Factors; C000715348:ARF6 protein, human; C000715349:Arf6 protein, rat
keywords: 7-helix receptor; ADP ribosylation factor (ARF); angiotensin II; arrestin; cell migration; vascular smooth muscle cells