Molecular mechanism of the recruitment of NBS1/hMRE11/hRAD50 complex to DNA double-strand breaks: NBS1 binds to gamma-H2AX through FHA/BRCT domain.
DNA double-strand breaks represent the most potentially serious damage to a genome, and hence, many repair proteins are recruited to DNA damage sites by as yet poorly characterized sensor mechanisms. We clarified that NBS1 physically interacts with gamma-H2AX to form nuclear foci at DNA damage sites. The fork-head associated (FHA) and the BRCA1 C-terminal domains (BRCT) of NBS1 are essential for this physical interaction and focus formation of NBS1 in response to DNA damage. The inhibition of this interaction by introduction of anti-gamma-H2AX antibody into cells abolishes NBS1 foci formation in response to DNA damage. Consequently, the FHA/BRCT domain is likely to have a crucial role for both binding to histone and for re-localization of the NBS1/hMRE11/hRAD50 complex to the vicinity of DNA damage. Moreover, the foci formation of DNA repair-related proteins containing BRCT domain, such as BRCA1, requires the interaction with gamma-H2AX in response to DNA damage. These findings indicate that the physical interaction between gamma-H2AX and DNA repair-related proteins is indispensable for the recruitment of these proteins. Further, it was recently reported that the NBS1/hMRE11/hRAD50 complex has a crucial role for both the recruitment of ATM to DNA damage sites and the subsequent activation of ATM. Therefore, both gamma-H2AX and the NBS1/hMRE11/hRAD50 complex might function for the initial recognition of DNA damage.
Kobayashi
Junya
J
Department of Oral and Maxillofacial Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Japan. jfukami@hiroshima-u.ac.jp
D017766:Acid Anhydride Hydrolases; D000818:Animals; D017209:Apoptosis; D019313:BRCA1 Protein / Q000235:genetics; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D000076228:MRE11 Homologue Protein; D051379:Mice; D008954:Models, Biological; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary
D019313:BRCA1 Protein; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; C121766:MRE11 protein, human; C512689:Mre11a protein, mouse; C112156:NBN protein, human; D009687:Nuclear Proteins; D000076228:MRE11 Homologue Protein; D017766:Acid Anhydride Hydrolases; C112158:RAD50 protein, human; D045643:DNA Repair Enzymes