Table 4 The ATM Protein (reviewed in [110])

• 3056 amino acids

• Serine/Threonine protein kinase

• Member of the family of PI3 Kinase-like Kinases (PIKKs)

• Located primarily in the nucleus; smaller amounts in the cytoplasm and associated with mitochondria and peroxisomes [178]

• Activated primarily by DSBs and oxidative stress, but also agents affecting chromatin organization, hypoxia, hypotonic stress and hyperthermia

• Phosphorylates and regulates a variety of protein substrates involved in

  o The DNA damage response (NHEJ and HRR) to DSBs

  o Various other genotoxic stress responses

  o DNA repair processes

  o Cell cycle checkpoints

  o Other cell stress responses

  o Apoptosis