4J2Q

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.00 Å
  • R-Value Free: 0.279 
  • R-Value Work: 0.248 
  • R-Value Observed: 0.249 

Starting Model: experimental
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This is version 1.2 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: https://doi.org/10.1038/nature12133
  • Primary Citation of Related Structures:  
    4J2Q

  • 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 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:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
S-arrestin
A, B
380Bos taurusMutation(s): 0 
Gene Names: ARRS_BOVINSAG
UniProt
Find proteins for P08168 (Bos taurus)
Explore P08168 
Go to UniProtKB:  P08168
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP08168
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.00 Å
  • R-Value Free: 0.279 
  • R-Value Work: 0.248 
  • R-Value Observed: 0.249 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 102.494α = 90
b = 102.494β = 90
c = 464.396γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
MxCuBEdata collection
XDSdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-05-01
    Type: Initial release
  • Version 1.1: 2013-05-15
    Changes: Database references
  • Version 1.2: 2023-09-20
    Changes: Data collection, Database references, Refinement description