Details

Autor(en) / Beteiligte

• Oakley, Robert H.
• Laporte, Stéphane A.
• Holt, Jason A.
• Barak, Larry S.
• Caron, Marc G.

Titel

Molecular Determinants Underlying the Formation of Stable Intracellular G Protein-coupled Receptor-β-Arrestin Complexes after Receptor Endocytosis

Ist Teil von

• The Journal of biological chemistry, 2001-06, Vol.276 (22), p.19452-19460

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2001

Quelle

MEDLINE

Beschreibungen/Notizen

• β-Arrestins bind agonist-activated G protein-coupled receptors (GPCRs) and mediate their desensitization and internalization. Although β-arrestins dissociate from some receptors at the plasma membrane, such as the β2 adrenergic receptor, they remain associated with other GPCRs and internalize with them into endocytic vesicles. Formation of stable receptor-β-arrestin complexes that persist inside the cell impedes receptor resensitization, and the aberrant formation of these complexes may play a role in GPCR-based diseases (Barak, L. S., Oakley, R. H., Laporte, S. A., and Caron, M. G. (2001) Proc. Natl. Acad. Sci. U. S. A. 98, 93–98). Here, we investigate the molecular determinants responsible for sustained receptor/β-arrestin interactions. We show in real time and in live human embryonic kidney (HEK-293) cells that a β-arrestin-2-green fluorescent protein conjugate internalizes into endocytic vesicles with agonist-activated neurotensin-1 receptor, oxytocin receptor, angiotensin II type 1A receptor, and substance P receptor. Using receptor mutagenesis, we demonstrate that the ability of β-arrestin to remain associated with these receptors is mediated by specific clusters of serine and threonine residues located in the receptor carboxyl-terminal tail. These clusters are remarkably conserved in their position within the carboxyl-terminal domain and serve as primary sites of agonist-dependent receptor phosphorylation. In addition, we identify a β-arrestin mutant with enhanced affinity for the agonist-activated β2-adrenergic receptor that traffics into endocytic vesicles with receptors that lack serine/threonine clusters and normally dissociate from wild-type β-arrestin at the plasma membrane. By identifying receptor and β-arrestin residues critical for the formation of stable receptor-β-arrestin complexes, these studies provide novel targets for regulating GPCR responsiveness and treating diseases resulting from abnormal GPCR/β-arrestin interactions.