Structure of the N-terminal I-BAR domain (1-259) of D.Discoideum IBARa

Experimental Data Snapshot

  • Resolution: 2.21 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.196 

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The inverse BAR domain protein IBARa drives membrane remodeling to control osmoregulation, phagocytosis and cytokinesis.

Linkner, J.Witte, G.Zhao, H.Junemann, A.Nordholz, B.Runge-Wollmann, P.Lappalainen, P.Faix, J.

(2014) J Cell Sci 127: 1279-1292

  • DOI: https://doi.org/10.1242/jcs.140756
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Here, we analyzed the single inverse Bin/Amphiphysin/Rvs (I-BAR) family member IBARa from Dictyostelium discoideum. The X-ray structure of the N-terminal I-BAR domain solved at 2.2 Å resolution revealed an all-α-helical structure that self-associates into a 165-Å zeppelin-shaped antiparallel dimer. The structural data are consistent with its shape in solution obtained by small-angle X-ray scattering. Cosedimentation, fluorescence anisotropy, and fluorescence and electron microscopy revealed that the I-BAR domain bound preferentially to phosphoinositide-containing vesicles and drove the formation of negatively curved tubules. Immunofluorescence labeling further showed accumulation of endogenous IBARa at the tips of filopodia, the rim of constricting phagocytic cups, in foci connecting dividing cells during the final stage of cytokinesis and most prominently at the osmoregulatory contractile vacuole (CV). Consistently, IBARa-null mutants displayed defects in CV formation and discharge, growth, phagocytosis and mitotic cell division, whereas filopodia formation was not compromised. Of note, IBARa-null mutants were also strongly impaired in cell spreading. Taken together, these data suggest that IBARa constitutes an important regulator of numerous cellular processes intimately linked with the dynamic rearrangement of cellular membranes.

  • Organizational Affiliation

    Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
SH3 domain-containing protein
A, B, C, D
264Dictyostelium discoideumMutation(s): 0 
Gene Names: DDB_G0274805
Find proteins for C7FZZ0 (Dictyostelium discoideum)
Explore C7FZZ0 
Go to UniProtKB:  C7FZZ0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupC7FZZ0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.21 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.194 
  • R-Value Observed: 0.196 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.1α = 90
b = 60.21β = 100.38
c = 147.62γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-02-05
    Type: Initial release
  • Version 1.1: 2014-04-02
    Changes: Database references