MDC1 Directly Binds Phosphorylated Histone H2AX to Regulate Cellular Responses to DNA Double-Strand Breaks
Stucki, M., Clapperton, J.A., Mohammad, D., Yaffe, M.B., Smerdon, S.J., Jackson, S.P.(2005) Cell 123: 1213-1226
- PubMed: 16377563 
- DOI: https://doi.org/10.1016/j.cell.2005.09.038
- Primary Citation of Related Structures:  
2AZM - PubMed Abstract: 
Histone variant H2AX phosphorylation in response to DNA damage is the major signal for recruitment of DNA-damage-response proteins to regions of damaged chromatin. Loss of H2AX causes radiosensitivity, genome instability, and DNA double-strand-break repair defects, yet the mechanisms underlying these phenotypes remain obscure. Here, we demonstrate that mammalian MDC1/NFBD1 directly binds to phospho-H2AX (gammaH2AX) by specifically interacting with the phosphoepitope at the gammaH2AX carboxyl terminus. Moreover, through a combination of biochemical, cell-biological, and X-ray crystallographic approaches, we reveal the molecular details of the MDC1/NFBD1-gammaH2AX complex. These data provide compelling evidence that the MDC1/NFBD1 BRCT repeat domain is the major mediator of gammaH2AX recognition following DNA damage. We further show that MDC1/NFBD1-gammaH2AX complex formation regulates H2AX phosphorylation and is required for normal radioresistance and efficient accumulation of DNA-damage-response proteins on damaged chromatin. Thus, binding of MDC1/NFBD1 to gammaH2AX plays a central role in the mammalian response to DNA damage.
Organizational Affiliation: 
The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Zoology, Cambridge University, Tennis Court Road, Cambridge CB2 1QN, United Kingdom.