Functional interaction between DNA-PK and c-Abl in response to DNA damage.
How DNA damage is converted into intracellular signals that can control cell behaviour is unknown. The c-Abl protein tyrosine kinase is activated by ionizing radiation and certain other DNA-damaging agents, whereas the DNA-dependent protein kinase (DNA-PK), consisting of a serine/threonine kinase and Ku DNA-binding subunits, requires DNA double-strand breaks or other DNA lesions for activation. Here we demonstrate that c-Abl interacts constitutively with DNA-PK. Ionizing radiation stimulates binding of c-Abl to DNA-PK and induces an association of c-Abl with Ku antigen. We show that DNA-PK phosphorylates and activates c-Abl in vitro. Cells deficient in DNA-PK are defective in c-Abl activation induced by ionizing radiation. In a potential feedback mechanism, c-Abl phosphorylates DNA-PK, but not Ku, in vitro. Phosphorylation of DNA-PK by c-Abl inhibits the ability of DNA-PK to form a complex with DNA. We also show that treatment of cells with ionizing radiation results in phosphorylation of DNA-PK that is dependent on c-Abl. Our results support the hypothesis that there are functional interactions between c-Abl and DNA-PK in the response to DNA damage.
Kharbanda
S
S
Division of Cancer Pharmacology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
Pandey
P
P
Jin
S
S
Inoue
S
S
Bharti
A
A
Yuan
Z M
ZM
Weichselbaum
R
R
Weaver
D
D
Kufe
D
D
D000818:Animals; D034961:Antigens, Nuclear; D002460:Cell Line; D004249:DNA Damage; D004265:DNA Helicases; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins / Q000378:metabolism; D004789:Enzyme Activation; D000072200:Ku Autoantigen; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding / Q000528:radiation effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016315:Proto-Oncogene Proteins c-abl / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism; D018909:src Homology Domains
D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D014443:Tyrosine; D016315:Proto-Oncogene Proteins c-abl; D051747:DNA-Activated Protein Kinase; D017346:Protein Serine-Threonine Kinases; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; C000606510:Xrcc6 protein, mouse; D000072200:Ku Autoantigen