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

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

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arrestins / chemistry*
  • Arrestins / genetics
  • Arrestins / metabolism
  • Humans
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Rhodopsin / chemistry*
  • Rhodopsin / genetics
  • Rhodopsin / metabolism
  • Signal Transduction*
  • Spin Labels

Substances

  • Arrestins
  • Spin Labels
  • arrestin3
  • Rhodopsin

Associated data

  • PDB/1G4M
  • PDB/3P2D
  • PDB/4JQI