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[p53 activation by PI-3K family kinases after DNA double-strand breaks]
D Pernin1, N Uhrhammer, P Verrelle
1Laboratoire d'oncologie moléculaire, de lutte contre le cancer. Centre Jean-Perrin, 58, rue Montalembert, BP 392, 63011 Clermont-Ferrand Cedex 1.
Abstract:
p53 plays a central role in the cellular response to DNA double-strand breaks (DSBs), and to DNA damage in general. The protein kinases ATM, ATR and DNA-PK detect DSBs and transmit this information to p53 by phosphorylation. This phosphorylation dissociates p53 from its negative regulator, mdm2. p53 then undergoes further modification and activates transcription of the genes responsible for cell cycle arrest. In certain circumstances, p53 also activates transcription of the genes responsible for apoptosis. The dysfunction of this cascade of events is oncogenic, with P53 itself being the most commonly mutated gene in malignant cells, although mutations in both the DNA damage sensors and cell cycle checkpoint and apoptosis effectors are frequent. A more complete understanding of p53 and the proteins it interacts with may allow the development of new cancer treatments.
Insights
The p53 protein is crucial for DNA repair and preventing cancer. Its pathway, involving kinases like ATM and ATR, regulates cell cycle arrest and apoptosis. Understanding this pathway could lead to new cancer therapies.
Area of Science:
- Molecular Biology
- Cell Biology
- Cancer Biology
Background:
- The p53 protein is a critical component in the cellular response to DNA damage, particularly DNA double-strand breaks (DSBs).
- Key protein kinases, including ATM, ATR, and DNA-PK, act as sensors for DSBs and initiate signaling cascades.
- Dysregulation of the p53 pathway is frequently observed in cancer, with mutations in p53 and associated proteins being common.
Purpose of the Study:
- To elucidate the central role of p53 in the DNA damage response pathway.
- To describe the mechanism by which p53 is activated and regulates downstream genes.
- To highlight the implications of p53 pathway dysfunction in oncogenesis and potential therapeutic strategies.
Main Methods:
- The study focuses on the molecular interactions and signaling events within the p53 pathway.
- It involves understanding the phosphorylation of p53 by upstream kinases (ATM, ATR, DNA-PK).
- Analysis of transcriptional activation of genes involved in cell cycle arrest and apoptosis.
Main Results:
- Phosphorylation of p53 by ATM, ATR, and DNA-PK leads to its dissociation from the negative regulator mdm2.
- Activated p53 triggers the transcription of genes essential for cell cycle arrest.
- Under specific conditions, p53 also induces the transcription of pro-apoptotic genes.
Conclusions:
- The p53 pathway is fundamental for maintaining genomic stability and preventing cancer.
- Mutations in p53, DNA damage sensors, or downstream effectors contribute to cancer development.
- A deeper comprehension of the p53 interactome may pave the way for novel cancer treatment modalities.