4J2Q

Crystal structure of C-terminally truncated arrestin reveals mechanism of arrestin activation


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.279 
  • R-Value Work: 0.248 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal structure of pre-activated arrestin p44.

Kim, Y.J.Hofmann, K.P.Ernst, O.P.Scheerer, P.Choe, H.W.Sommer, M.E.

(2013) Nature 497: 142-146

  • DOI: 10.1038/nature12133

  • PubMed Abstract: 
  • Arrestins interact with G-protein-coupled receptors (GPCRs) to block interaction with G proteins and initiate G-protein-independent signalling. Arrestins have a bi-lobed structure that is stabilized by a long carboxy-terminal tail (C-tail), and displ ...

    Arrestins interact with G-protein-coupled receptors (GPCRs) to block interaction with G proteins and initiate G-protein-independent signalling. Arrestins have a bi-lobed structure that is stabilized by a long carboxy-terminal tail (C-tail), and displacement of the C-tail by receptor-attached phosphates activates arrestins for binding active GPCRs. Structures of the inactive state of arrestin are available, but it is not known how C-tail displacement activates arrestin for receptor coupling. Here we present a 3.0 Å crystal structure of the bovine arrestin-1 splice variant p44, in which the activation step is mimicked by C-tail truncation. The structure of this pre-activated arrestin is profoundly different from the basal state and gives insight into the activation mechanism. p44 displays breakage of the central polar core and other interlobe hydrogen-bond networks, leading to a ∼21° rotation of the two lobes as compared to basal arrestin-1. Rearrangements in key receptor-binding loops in the central crest region include the finger loop, loop 139 (refs 8, 10, 11) and the sequence Asp 296-Asn 305 (or gate loop), here identified as controlling the polar core. We verified the role of these conformational alterations in arrestin activation and receptor binding by site-directed fluorescence spectroscopy. The data indicate a mechanism for arrestin activation in which C-tail displacement releases critical central-crest loops from restricted to extended receptor-interacting conformations. In parallel, increased flexibility between the two lobes facilitates a proper fitting of arrestin to the active receptor surface. Our results provide a snapshot of an arrestin ready to bind the active receptor, and give an insight into the role of naturally occurring truncated arrestins in the visual system.


    Organizational Affiliation

    Institut für Medizinische Physik und Biophysik (CC2), Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
S-arrestin
A, B
380Bos taurusMutation(s): 0 
Gene Names: SAG
Find proteins for P08168 (Bos taurus)
Go to Gene View: SAG
Go to UniProtKB:  P08168
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.279 
  • R-Value Work: 0.248 
  • Space Group: P 61 2 2
Unit Cell:
Length (Å)Angle (°)
a = 102.494α = 90.00
b = 102.494β = 90.00
c = 464.396γ = 120.00
Software Package:
Software NamePurpose
REFMACrefinement
MxCuBEdata collection
SCALAdata scaling
PHASERphasing
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-05-01
    Type: Initial release
  • Version 1.1: 2013-05-15
    Type: Database references