Purified anti-ATM Phospho (Ser1981)

Ataxia telangiectasia mutated kinase (ATM) is a serine/threonine kinase that regulates cell cycle checkpoints and DNA repair. ATM is held inactive in unirradiated cells as a dimer or higher-order multimer. Cellular irradiation induces rapid intermolecular autophosphorylation of serine 1981 that causes dimer dissociation and initiates cellular ATM kinase activity. ATM kinase regulates a number of proteins involved in cell cycle checkpoint control, apoptosis, and DNA repair, including tumor suppressor proteins p53 and BRCA1, checkpoint kinase CHK2, checkpoint proteins RAD17 and RAD9, and DNA repair protein NBS1. Mutations in the corresponding ATM gene result in ataxia telangiectasia (AT), an autosomal recessive disease characterized by uncoordinated muscle movement and neurodegeneration. Cells from AT patients display defective DNA damage-induced checkpoint activation, sensitivity to radiation, and a higher frequency of chromosome breakage.