Ataxia telangiectasia mutated (ATM) and ATM and RAD3-related (ATR) are members of the phosphatidylinositol 3-kinase (PI 3-kinase) like family of protein kinases (PIKKs). These large proteins predicted molecular masses for ATM and ATR are 351 kDa and 301 kDa, respectively are involved in cellular responses to DNA damage.
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