The protein is named for the disorder Ataxia telangiectasia caused by mutations of ATM. The protein encoded by this gene belongs to the PI3/PI4-kinase family. ATM is swiftly activated following the induction of DSBs in the DNA, and subsequently phosphorylates several key proteins that initiate activation of the DNA damage checkpoint, leading to cell cycle arrest, DNA repair or apoptosis. Thus, it functions as a regulator of a wide variety of downstream proteins, including tumor suppressor proteins p53 and BRCA1, checkpoint kinase CHK2, checkpoint proteins RAD17 and RAD9, and DNA repair protein NBS1. These phosphorylations, and often additional post-translational modifications carried out by ATM-activated enzymes, can affect the activity, stability, subcellular location and interactions with other proteins of these ATM targets, thereby modulating the corresponding pathways and processes. This protein and the closely related kinase ATR are thought to be master controllers of cell cycle checkpoint signaling pathways that are required for cell response to DNA damage and for genome stability.
