Fragments of ATM which have dominant-negative or complementing activity.

Morgan SE, Lovly C, Pandita TK, Shiloh Y, Kastan MB
Mol Cell Biol. 1997 17 (4): 2020-9

PMID: 9121450 · PMCID: PMC232049 · DOI:10.1128/mcb.17.4.2020

The ATM protein has been implicated in pathways controlling cell cycle checkpoints, radiosensitivity, genetic instability, and aging. Expression of ATM fragments containing a leucine zipper motif in a human tumor cell line abrogated the S-phase checkpoint after ionizing irradiation and enhanced radiosensitivity and chromosomal breakage. These fragments did not abrogate irradiation-induced G1 or G2 checkpoints, suggesting that cell cycle checkpoint defects alone cannot account for chromosomal instability in ataxia telangiectasia (AT) cells. Expression of the carboxy-terminal portion of ATM, which contains the PI-3 kinase domain, complemented radiosensitivity and the S-phase checkpoint and reduced chromosomal breakage after irradiation in AT cells. These observations suggest that ATM function is dependent on interactions with itself or other proteins through the leucine zipper region and that the PI-3 kinase domain contains much of the significant activity of ATM.

MeSH Terms (24)

Ataxia Telangiectasia Ataxia Telangiectasia Mutated Proteins Base Sequence Cell Cycle Cell Cycle Proteins Cell Survival Chromosome Aberrations DNA DNA, Complementary DNA-Binding Proteins DNA Damage DNA Primers Genes, p53 Genetic Complementation Test Humans Leucine Zippers Peptide Fragments Phenotype Phosphatidylinositol 3-Kinases Phosphotransferases (Alcohol Group Acceptor) Protein-Serine-Threonine Kinases Proteins Radiation Tolerance Tumor Suppressor Proteins

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