Furthermore, p97 can be phosphorylated on Ser457, Ser459, and Ser326 (buried) by ATM (ataxia telangiectasia-mutated) and ATR (ATM-Rad3-related), the two proximal checkpoint kinases, which regulate the DNA damage response (DDR) (Mu et al., 2007). Here, ATM is linked to ataxia telangiectasia.