ATM

Newly discovered cellular process helps cells respond to DNA damage caused by radiation and environmental toxins: "A report on this discovery, published in the current issue of the journal Nature, describes this critical early step in a cell's response to DNA damage. This step, a chemical modification of an enzyme called ATM, allows the enzyme to initiate a series of events that ultimately halt the growth of a damaged cell and help the cell survive.

ATM is activated by a signal from damaged DNA only seconds after the damage occurs. The activated ATM, in turn, activates other proteins by attaching a molecule called “phosphate” to them in a process called phosphorylation. This sets off a cascade of biochemical reactions that amplifies the initial ATM response.

Among the proteins phosphorylated by ATM are Brca1 and p53. It was already known that these proteins play important roles in preventing cancer, and that mutated forms of Brca1 and p53 are responsible for inherited cancers, such as familial breast cancer."