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Title: β-arrestins negatively control human adrenomedullin type 1-receptor internalization

Journal Article · · Biochemical and Biophysical Research Communications
 [1]; ;  [2];  [3];  [1];  [4];  [5];  [1]
  1. Frontier Science Research Center, University of Miyazaki, Miyazaki 889-1692 (Japan)
  2. Division of Circulation and Body Fluid Regulation, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692 (Japan)
  3. Noto Marine Laboratory, Institute of Nature and Environmental Technology, Division of Marine Environmental Studies, Kanazawa University, Ishikawa 927-0553 (Japan)
  4. Department of Pharmacology, Hirosaki University, Graduate School of Medicine, Hirosaki 036-8562 (Japan)
  5. Department of Molecular and Medical Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194 (Japan)

Adrenomedullin (AM) is a potent hypotensive peptide that exerts a powerful variety of protective effects against multiorgan damage through the AM type 1 receptor (AM{sub 1} receptor), which consists of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 2 (RAMP2). Two β-arrestin (β-arr) isoforms, β-arr-1 and β-arr-2, play a central role in the agonist-induced internalization of many receptors for receptor resensitization. Notably, β-arr-biased agonists are now being tested in phase II clinical trials, targeting acute pain and acute heart failure. Here, we examined the effects of β-arr-1 and β-arr-2 on human AM{sub 1} receptor internalization. We constructed a V5-tagged chimera in which the cytoplasmic C-terminal tail (C-tail) of CLR was replaced with that of the β{sub 2}-adrenergic receptor (β{sub 2}-AR), and it was transiently transfected into HEK-293 cells that stably expressed RAMP2. The cell-surface expression and internalization of the wild-type or chimeric receptor were quantified by flow cytometric analysis. The [{sup 125}I]AM binding and the AM-induced cAMP production of these receptors were also determined. Surprisingly, the coexpression of β-arr-1 or -2 resulted in significant decreases in AM{sub 1} receptor internalization without affecting AM binding and signaling prior to receptor internalization. Dominant-negative (DN) β-arr-1 or -2 also significantly decreased AM-induced AM{sub 1} receptor internalization. In contrast, the AM-induced internalization of the chimeric AM{sub 1} receptor was markedly augmented by the cotransfection of β-arr-1 or -2 and significantly reduced by the coexpression of DN-β-arr-1 or -2. These results were consistent with those seen for β{sub 2}-AR. Thus, both β-arrs negatively control AM{sub 1} receptor internalization, which depends on the C-tail of CLR. - Highlights: • We found that β-arrestins 1 and 2 negatively control agonist-induced GPCR internalization. • β-arrestins 1 and 2 significantly inhibits the AM-induced internalization of human CLR/RAMP2. • The inhibitory effects of both β-arrestins are dependent on the C-terminal tail of CLR.

OSTI ID:
22697037
Journal Information:
Biochemical and Biophysical Research Communications, Vol. 487, Issue 2; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
Country of Publication:
United States
Language:
English