Cyclin-dependent kinases and P53 pathways are activated independently and mediate Bax activation in neurons after DNA damage.
DNA damage has been implicated as one important initiator of cell death in neuropathological conditions such as stroke. Accordingly, it is important to understand the signaling processes that control neuronal death induced by this stimulus. Previous evidence has shown that the death of embryonic cortical neurons treated with the DNA-damaging agent camptothecin is dependent on the tumor suppressor p53 and cyclin-dependent kinase (CDK) activity and that the inhibition of either pathway alone leads to enhanced and prolonged survival. We presently show that p53 and CDKs are activated independently on parallel pathways. An increase in p53 protein levels, nuclear localization, and DNA binding that result from DNA damage are not affected by the inhibition of CDK activity. Conversely, no decrease in retinoblastoma protein (pRb) phosphorylation was observed in p53-deficient neurons that were treated with camptothecin. However, either p53 deficiency or the inhibition of CDK activity alone inhibited Bax translocation, cytochrome c release, and caspase-3-like activation. Taken together, our results indicate that p53 and CDK are activated independently and then act in concert to control Bax-mediated apoptosis.
Morris
E J
EJ
Massachusetts General Hospital Cancer Center, Laboratory of Molecular Oncology, Charlestown, Massachusetts 02129, USA.
Keramaris
E
E
Rideout
H J
HJ
Slack
R S
RS
Dyson
N J
NJ
Stefanis
L
L
Park
D S
DS
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000502:physiology; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002166:Camptothecin / Q000494:pharmacology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003574:Cytochrome c Group / Q000378:metabolism; D004249:DNA Damage / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2; D016160:Retinoblastoma Protein / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000378:metabolism*; D051028:bcl-2-Associated X Protein
C494827:Bax protein, mouse; D003574:Cytochrome c Group; D004791:Enzyme Inhibitors; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D018844:Cyclin-Dependent Kinases; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D002166:Camptothecin