
Ataxia telangiectasia mutant protein activates c-Abl tyrosine kinase in response to ionizing radiation.
Ataxia telangiectasia (AT) is a rare human autosomal recessive disorder with pleiotropic phenotypes, including neuronal degeneration, immune dysfunction, premature ageing and increased cancer risk. The gene mutated in AT, ATM, encodes a putative lipid or protein kinase. Most of the human AT patient phenotypes are recapitulated in Atm-deficient mice. Cells derived from Atm-/- mice, like those from AT patients, exhibit abnormal response to ionizing radiation. One of the known responses to ionizing radiation is the activation of a nuclear tyrosine kinase encoded by the c-abl proto-oncogene. Ionizing radiation does not activate c-Abl in cells from AT patients or in thymocytes or fibroblasts from the Atm-deficient mice. Ectopic expression of a functional ATM kinase domain corrects this defect, as it phosphorylates the c-Abl tyrosine kinase in vitro at Ser 465, leading to the activation of c-Abl. A mutant c-Abl with Ser 465 changed to Ala 465 is not activated by ionizing radiation or ATM kinase in vivo. These findings identify the c-Abl tyrosine kinase as a downstream target of phosphorylation and activation by the ATM kinase in the cellular response to ionizing radiation.
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Related Subject Headings
- Tumor Suppressor Proteins
- Transfection
- RNA Polymerase II
- Proto-Oncogene Proteins c-abl
- Proto-Oncogene Mas
- Proteins
- Protein Serine-Threonine Kinases
- Mice
- Humans
- General Science & Technology
Citation

Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Tumor Suppressor Proteins
- Transfection
- RNA Polymerase II
- Proto-Oncogene Proteins c-abl
- Proto-Oncogene Mas
- Proteins
- Protein Serine-Threonine Kinases
- Mice
- Humans
- General Science & Technology