Crystal Structure of the human MDC1 FHA Domain

Experimental Data Snapshot

  • Resolution: 1.65 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.235 
  • R-Value Observed: 0.236 

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Structural mechanism of the phosphorylation-dependent dimerization of the MDC1 forkhead-associated domain

Liu, J.Luo, S.Zhao, H.Liao, J.Li, J.Yang, C.Xu, B.Stern, D.F.Xu, X.Ye, K.

(2012) Nucleic Acids Res 40: 3898-3912

  • DOI: https://doi.org/10.1093/nar/gkr1296
  • Primary Citation of Related Structures:  
    3UMZ, 3UNM, 3UNN

  • PubMed Abstract: 

    MDC1 is a key mediator of the DNA-damage response in mammals with several phosphorylation-dependent protein interaction domains. The function of its N-terminal forkhead-associated (FHA) domain remains elusive. Here, we show with structural, biochemical and cellular data that the FHA domain mediates phosphorylation-dependent dimerization of MDC1 in response to DNA damage. Crystal structures of the FHA domain reveal a face-to-face dimer with pseudo-dyad symmetry. We found that the FHA domain recognizes phosphothreonine 4 (pT4) at the N-terminus of MDC1 and determined its crystal structure in complex with a pT4 peptide. Biochemical analysis further revealed that in the dimer, the FHA domain binds in trans to pT4 from the other subunit, which greatly stabilizes the otherwise unstable dimer. We show that T4 is phosphorylated primarily by ATM upon DNA damage. MDC1 mutants with the FHA domain deleted or impaired in its ability to dimerize formed fewer foci at DNA-damage sites, but the localization defect was largely rescued by an artificial dimerization module, suggesting that dimerization is the primary function of the MDC1 FHA domain. Our results suggest a novel mechanism for the regulation of MDC1 function through T4 phosphorylation and FHA-mediated dimerization.

  • Organizational Affiliation

    Beijing Key Laboratory of DNA Damage Response and College of Life Science, Capital Normal University, Beijing 100048, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Mediator of DNA damage checkpoint protein 1
A, B
113Homo sapiensMutation(s): 0 
Gene Names: MDC1KIAA0170NFBD1
UniProt & NIH Common Fund Data Resources
Find proteins for Q14676 (Homo sapiens)
Explore Q14676 
Go to UniProtKB:  Q14676
PHAROS:  Q14676
GTEx:  ENSG00000137337 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ14676
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.65 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.235 
  • R-Value Observed: 0.236 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.987α = 90
b = 58.856β = 90
c = 67.046γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

  • Released Date: 2012-01-25 
  • Deposition Author(s): Luo, S., Ye, K.

Revision History  (Full details and data files)

  • Version 1.0: 2012-01-25
    Type: Initial release
  • Version 1.1: 2014-03-12
    Changes: Database references
  • Version 1.2: 2017-11-08
    Changes: Refinement description
  • Version 1.3: 2024-03-20
    Changes: Data collection, Database references