Experimental Data Snapshot

  • Resolution: 2.80 Å
  • R-Value Free: 0.275 
  • R-Value Work: 0.234 

wwPDB Validation   3D Report Full Report

This is version 1.4 of the entry. See complete history


The structural basis of Arfaptin-mediated cross-talk between Rac and Arf signalling pathways.

Tarricone, C.Xiao, B.Justin, N.Walker, P.A.Rittinger, K.Gamblin, S.J.Smerdon, S.J.

(2001) Nature 411: 215-219

  • DOI: https://doi.org/10.1038/35075620
  • Primary Citation of Related Structures:  
    1I49, 1I4D, 1I4L, 1I4T

  • PubMed Abstract: 

    Small G proteins are GTP-dependent molecular switches that regulate numerous cellular functions. They can be classified into homologous subfamilies that are broadly associated with specific biological processes. Cross-talk between small G-protein families has an important role in signalling, but the mechanism by which it occurs is poorly understood. The coordinated action of Arf and Rho family GTPases is required to regulate many cellular processes including lipid signalling, cell motility and Golgi function. Arfaptin is a ubiquitously expressed protein implicated in mediating cross-talk between Rac (a member of the Rho family) and Arf small GTPases. Here we show that Arfaptin binds specifically to GTP-bound Arf1 and Arf6, but binds to Rac.GTP and Rac.GDP with similar affinities. The X-ray structure of Arfaptin reveals an elongated, crescent-shaped dimer of three-helix coiled-coils. Structures of Arfaptin with Rac bound to either GDP or the slowly hydrolysable analogue GMPPNP show that the switch regions adopt similar conformations in both complexes. Our data highlight fundamental differences between the molecular mechanisms of Rho and Ras family signalling, and suggest a model of Arfaptin-mediated synergy between the Arf and Rho family signalling pathways.

  • Organizational Affiliation

    Division of Protein Structure, National Institute for Medical Research, Mill Hill, London NW7 IAA, UK.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
224Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P53365 (Homo sapiens)
Explore P53365 
Go to UniProtKB:  P53365
GTEx:  ENSG00000132254 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP53365
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.80 Å
  • R-Value Free: 0.275 
  • R-Value Work: 0.234 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 146.334α = 90
b = 146.334β = 90
c = 82.732γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-05-16
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Data collection
  • Version 1.4: 2024-02-07
    Changes: Data collection, Database references