ATM belongs to the phosphatidylinositol-3′ kinase-related kinase (PIKK) family. It has a critical role in the maintenance of genome integrity.  In response to agents that generate DNA double-strand breaks (DSBs), inactive dimeric ATM protein dissociates into phosphorylated monomers. The MRN (Mre11-Rad50-Nbs1)-ATM pathway is essential for sensing and signaling from...