Nijmegen breakage syndrome protein 1 (NBS1) is a component of the MRE11/RAD50/NBN (MRN) complex, which plays a critical role in the cellular response to DNA damage and the maintenance of chromosome integrity. The complex is involved in double-strand break (DSB) repair, DNA recombination, maintenance of telomere integrity, cell cycle checkpoint control and meiosis. NBS1 modulates the DNA damage signal sensing by recruiting PI3/PI4-kinase family members ATM, ATR, and probably DNA-PKcs to the DNA damage sites and activating their functions. Defects in NBS1 are the cause of Nijmegen breakage syndrome, cancer predisposition, and anemia.The synthetic peptide used to raise the antibody Cat. No. 200163 is selected from a sequence within the C-term region of human NBS1. For blocking experiments, a 10 to 100 fold molar excess to antibody is recommended.