Ataxia telangiectasia mutated (ATM) interacts with p400 ATPase for an efficient DNA damage response.
Ataxia telangiectasia mutated (ATM) and TRRAP proteins belong to the phosphatidylinositol 3-kinase-related kinase family and are involved in DNA damage repair and chromatin remodeling. ATM is a checkpoint kinase that is recruited to sites of DNA double-strand breaks where it phosphorylates a diverse range of proteins that are part of the chromatin and DNA repair machinery. As an integral subunit of the TRRAP-TIP60 complexes, p400 ATPase is a chromatin remodeler that is also targeted to DNA double-strand break sites. While it is understood that DNA binding transcriptional activators recruit p400 ATPase into a regulatory region of the promoter, how p400 recognises and moves to DNA double-strand break sites is far less clear. Here we investigate a possibility whether ATM serves as a shuttle to deliver p400 to break sites.



Our data indicate that p400 co-immunoprecipitates with ATM independently of DNA damage state and that the N-terminal domain of p400 is vital for this interaction. Heterologous expression studies using Sf9 cells revealed that the ATM-p400 complex can be reconstituted without other mammalian bridging proteins. Overexpression of ATM-interacting p400 regions in U2OS cells induced dominant negative effects including the inhibition of both DNA damage repair and cell proliferation. Consistent with the dominant negative effect, the stable expression of an N-terminal p400 fragment showed a decrease in the association of p400 with ATM, but did not alter the association of p400 with TRRAP.



Taken together, our findings suggest that a protein-protein interaction between ATM and p400 ATPase occurs independently of DNA damage and contributes to efficient DNA damage response and repair.
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
Rebecca J
RJ
Smith
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
Matthew S
MS
Savoian
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
Lauren E
LE
Weber
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand. j.park@massey.ac.nz.
Jeong Hyeon
JH
Park
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism*; D002460:Cell Line; D004249:DNA Damage; D004265:DNA Helicases / Q000378:metabolism*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism*; D057809:HEK293 Cells; D051548:Histone Acetyltransferases / Q000378:metabolism; D006801:Humans; D007313:Insecta; D000074443:Lysine Acetyltransferase 5; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D060066:Protein Interaction Maps; D061987:Sf9 Cells
D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C113829:transformation-transcription domain-associated protein; D051548:Histone Acetyltransferases; C098489:KAT5 protein, human; D000074443:Lysine Acetyltransferase 5; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D004265:DNA Helicases; C498558:EP400 protein, human
ATM; Chromatin remodelling; DNA damage response; DNA repair; Phosphatidylinositol 3-kinase; p400