title: The AT1A receptor "gain-of-function" mutant N111S/delta329 is both constitutively active and hyperreactive to angiotensin II.
abstract: The renin-angiotensin-aldosterone system (RAAS) is central to cardiovascular and renal physiology. However, there is no animal model in which the activation of the RAAS only reflects the activation of the angiotensin II (ANG II) AT1 receptor. As a first step to developing such a model, we characterized a gain-of-function mutant of the mouse AT1A receptor. This mutant carries two mutations: N111S predicted to activate the receptor constitutively and a COOH-terminal deletion, delta329, expected to reduce receptor internalization and desensitization. We expressed this double mutant (AT1A-N111S/delta329) in heterologous cells. It showed a pharmacological profile consistent with that of other constitutively active mutants. Furthermore, it increased basal production of inositol phosphates, as well as basal cytosolic and nuclear ERK activities. Basal proliferation of cells expressing the mutant was also greater than that of the wild type. The double mutant was poorly internalized and failed to recruit beta-arrestin 2 in the presence of ANG II. It also showed hypersensitive and hyperreactive responses to ANG II for both inositol phosphate production and ERK activation. The additivity of the phenotypes of the two mutations makes this mutant an appropriate candidate to test the physiological consequences of the AT1A receptor activation itself in transgenic animal models.
authors.affiliation: Institut Cochin, Département d'Endocrinologie, Paris, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Billet
authors.forename: Sabine
authors.initials: S
authors.lastname: Bardin
authors.forename: Rachida
authors.initials: R
authors.lastname: Tacine
authors.forename: Eric
authors.initials: E
authors.lastname: Clauser
authors.forename: Sophie
authors.initials: S
authors.lastname: Conchon
mesh_terms: D000804:Angiotensin II / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D057912:Angiotensin II Type 2 Receptor Blockers; D000818:Animals; D019390:Arrestins / Q000378:metabolism; D016466:CHO Cells; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D006224:Cricetinae; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000378:metabolism / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D011725:Pyridines / Q000378:metabolism / Q000494:pharmacology; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins
chemical_list: C000605254:ARRB2 protein, human; D057912:Angiotensin II Type 2 Receptor Blockers; C000605258:Arrb2 protein, mouse; D019390:Arrestins; D004791:Enzyme Inhibitors; D007093:Imidazoles; D007211:Indoles; D007295:Inositol Phosphates; D008301:Maleimides; D011725:Pyridines; D044140:Receptor, Angiotensin, Type 1; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins; D000804:Angiotensin II; C073402:PD 123319; C071924:Ro 31-8425; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3