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J Biol Chem. 2014 Jul 25;289(30):20991-1002. doi: 10.1074/jbc.M114.560680. Epub 2014 May 27.

Identification of receptor binding-induced conformational changes in non-visual arrestins.

Author information

1
From the Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and.
2
the Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
3
From the Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and candice@mcw.edu.

Abstract

The non-visual arrestins, arrestin-2 and arrestin-3, belong to a small family of multifunctional cytosolic proteins. Non-visual arrestins interact with hundreds of G protein-coupled receptors (GPCRs) and regulate GPCR desensitization by binding active phosphorylated GPCRs and uncoupling them from heterotrimeric G proteins. Recently, non-visual arrestins have been shown to mediate G protein-independent signaling by serving as adaptors and scaffolds that assemble multiprotein complexes. By recruiting various partners, including trafficking and signaling proteins, directly to GPCRs, non-visual arrestins connect activated receptors to diverse signaling pathways. To investigate arrestin-mediated signaling, a structural understanding of arrestin activation and interaction with GPCRs is essential. Here we identified global and local conformational changes in the non-visual arrestins upon binding to the model GPCR rhodopsin. To detect conformational changes, pairs of spin labels were introduced into arrestin-2 and arrestin-3, and the interspin distances in the absence and presence of the receptor were measured by double electron electron resonance spectroscopy. Our data indicate that both non-visual arrestins undergo several conformational changes similar to arrestin-1, including the finger loop moving toward the predicted location of the receptor in the complex as well as the C-tail release upon receptor binding. The arrestin-2 results also suggest that there is no clam shell-like closure of the N- and C-domains and that the loop containing residue 136 (homolog of 139 in arrestin-1) has high flexibility in both free and receptor-bound states.

KEYWORDS:

Arrestin; Electron Paramagnetic Resonance (EPR); G Protein-coupled Receptor (GPCR); Rhodopsin; Spectroscopy

PMID:
24867953
PMCID:
PMC4110305
DOI:
10.1074/jbc.M114.560680
[Indexed for MEDLINE]
Free PMC Article

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