Mn-ATM-p53 pathway. Following doubled-stranded DNA damage, ATM is activated by Mn to phosphorylate p53 and Mre11 of the MRN complex. The MRN complex is then able to repair the DNA damage. Abbreviations: ATM, ataxia telangiectasia mutated; Mn, manganese; MRN, Mre11, Rad50, Nbs1.