The sustainability of interactions between the orexin-1 receptor and beta-arrestin-2 is defined by a single C-terminal cluster of hydroxy amino acids and modulates the kinetics of ERK MAPK regulation.

Published

Journal Article

The orexin-1 receptor interacts with beta-arrestin-2 in an agonist-dependent manner. In HEK-293T cells, these two proteins became co-internalized into acidic endosomes. Truncations from the C-terminal tail did not prevent agonist-induced internalization of the orexin-1 receptor or alter the pathway of internalization, although such mutants failed to interact with beta-arrestin-2 in a sustained manner or produce its co-internalization. Mutation of a cluster of three threonine and one serine residue at the extreme C-terminus of the receptor greatly reduced interaction and abolished co-internalization of beta-arrestin-2-GFP (green fluorescent protein). Despite the weak interactions of this C-terminally mutated form of the receptor with beta-arrestin-2, studies in wild-type and beta-arrestin-deficient mouse embryo fibroblasts confirmed that agonist-induced internalization of this mutant required expression of a beta-arrestin. Although without effect on agonist-mediated elevation of intracellular Ca2+ levels, the C-terminally mutated form of the orexin-1 receptor was unable to sustain phosphorylation of the MAPKs (mitogen-activated protein kinases) ERK1 and ERK2 (extracellular-signal-regulated kinases 1 and 2) to the same extent as the wild-type receptor. These studies indicate that a single cluster of hydroxy amino acids within the C-terminal seven amino acids of the orexin-1 receptor determine the sustainability of interaction with beta-arrestin-2, and indicate an important role of beta-arrestin scaffolding in defining the kinetics of orexin-1 receptor-mediated ERK MAPK activation.

Full Text

Duke Authors

Cited Authors

  • Milasta, S; Evans, NA; Ormiston, L; Wilson, S; Lefkowitz, RJ; Milligan, G

Published Date

  • May 2005

Published In

Volume / Issue

  • 387 / Pt 3

Start / End Page

  • 573 - 584

PubMed ID

  • 15683363

Pubmed Central ID

  • 15683363

Electronic International Standard Serial Number (EISSN)

  • 1470-8728

International Standard Serial Number (ISSN)

  • 0264-6021

Digital Object Identifier (DOI)

  • 10.1042/BJ20041745

Language

  • eng