Structure of the actin-binding domain of human filamin A

Experimental Data Snapshot

  • Resolution: 2.30 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.250 
  • R-Value Observed: 0.252 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


Skeletal dysplasias due to filamin A mutations result from a gain-of-function mechanism distinct from allelic neurological disorders

Clark, A.R.Sawyer, G.M.Robertson, S.P.Sutherland-Smith, A.J.

(2009) Hum Mol Genet 18: 4791-4800

  • DOI: https://doi.org/10.1093/hmg/ddp442
  • Primary Citation of Related Structures:  
    3HOC, 3HOP, 3HOR

  • PubMed Abstract: 

    Filamin A (FLNA) crosslinks F-actin and binds proteins consistent with roles integrating cell signalling and the cytoskeleton. FLNA missense mutations are associated with the otopalatodigital syndrome (OPD) spectrum of skeletal disorders, clustering in discrete domains. One cluster is found in the second calponin homology domain of the FLNA actin-binding domain (ABD), implicating this region as essential for mediating correct function. Here we show that OPD (FLNA E254K) fibroblast lysates have equivalent concentrations of FLNA compared with controls and that recombinant FLNA E254K ABD has increased in vitro F-actin binding (K(d) 13 microm) compared with wild type (WT; K(d) 48 microm). These observations are consistent with a gain-of-function mechanism for OPD. We have determined the crystal structures of the WT and E254K FLNA ABDs at 2.3 A resolution, revealing that they adopt similar closed conformations. The E254K mutation removes a conserved salt bridge but does not disrupt the ABD structure. The solution structures are also equivalent as determined by circular dichroism spectroscopy, but differential scanning fluorimetry denaturation showed reduced stability (decreased T(m) of 5.6 degrees C) for E254K relative to WT. Ex vivo characterization of E254K OPD patient fibroblasts revealed they have similar motility and adhesion as control cells, implying that many core functions mediated by FLNA are unaffected, consistent with OPD only affecting specific tissues despite FLNA being widely expressed. These data provide the first biochemical evidence for a gain-of-function mechanism for the OPD disorders, and mechanistically distinguishes them from the loss-of-function phenotypes that manifest as disorders of neuronal migration.

  • Organizational Affiliation

    Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
272Homo sapiensMutation(s): 0 
Gene Names: FLNA
UniProt & NIH Common Fund Data Resources
Find proteins for P21333 (Homo sapiens)
Explore P21333 
Go to UniProtKB:  P21333
GTEx:  ENSG00000196924 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP21333
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.30 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.250 
  • R-Value Observed: 0.252 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.85α = 90
b = 71.22β = 90
c = 158.28γ = 90
Software Package:
Software NamePurpose
CrystalCleardata collection
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-10-13
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-11-01
    Changes: Refinement description
  • Version 1.3: 2023-11-01
    Changes: Data collection, Database references, Derived calculations, Refinement description