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The DNA binding regulatory domain of p53: see the C
1Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
Abstract:
The p53 tumor suppressor gene is a critical regulator of normal development involved in cell cycle control pathways, such as growth arrest, differentiation and apoptosis. The DNA binding activity of p53 is central to its function. In addition to the specific DNA binding activity that is confined to the "core" domain of the molecule, the C-terminus seems to play an important role in both controlling the specific as well as exhibiting a non-specific DNA binding activity, which is directly associated with sensing damaged DNA. The C-terminal DNA binding activity appears to be regulated by phosphorylation, glycosylation, splicing and binding of several factors. The C-terminus seems to recognize single and double stranded DNA breaks that occur during DNA replication and recombination, as well as following external DNA stress signals. Unless the cell manages to correct the DNA damage it has the tempting option to progress towards apoptosis. Imagine the C-terminus as a traffic light ensuring the safe "on going" through the cell cycle; in case damaged DNA could not be corrected, p53 dependent apoptosis or terminal differentiation "signs" are turned on!
Insights
The p53 tumor suppressor gene
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- The p53 tumor suppressor gene is crucial for normal development and cell cycle regulation.
- p53's DNA binding activity is essential for its tumor-suppressive functions.
- The C-terminus of p53 plays a key role in DNA binding and sensing DNA damage.
Purpose of the Study:
- To elucidate the role of the p53 C-terminus in DNA binding and damage response.
- To understand how post-translational modifications regulate p53's C-terminal DNA binding.
- To explore the function of p53 C-terminal DNA binding in cell cycle control and apoptosis.
Main Methods:
- Analysis of p53 DNA binding activities (specific and non-specific).
- Investigation of post-translational modifications (phosphorylation, glycosylation) affecting p53 C-terminus.
- Studying the recognition of DNA breaks by the p53 C-terminus.
Main Results:
- The p53 C-terminus exhibits non-specific DNA binding activity, crucial for sensing DNA damage.
- This C-terminal activity is modulated by phosphorylation, glycosylation, splicing, and factor binding.
- The p53 C-terminus recognizes single and double-stranded DNA breaks, integrating damage signals.
Conclusions:
- The p53 C-terminus acts as a critical sensor for DNA damage, regulating cell fate.
- p53-dependent apoptosis or differentiation is initiated when DNA damage cannot be repaired.
- The C-terminus functions as a regulatory hub, controlling the cell cycle in response to DNA integrity.