Decision making of the p53 network: death by integration

Area of Science:

• Molecular Biology
• Systems Biology
• Cell Biology

Background:

• The tumor suppressor protein p53 is a critical regulator of cellular responses to DNA damage.
• p53 orchestrates both pro-survival (cell cycle arrest, DNA repair) and pro-death (apoptosis) pathways.
• Understanding how p53 coordinates these opposing fates is crucial for deciphering cell fate decisions.

Purpose of the Study:

• To investigate the regulatory mechanisms by which the p53 network coordinates cell cycle arrest and apoptosis.
• To elucidate the strategy employed by p53 in making life-or-death decisions following DNA damage.
• To develop a mathematical model integrating key p53 network modules.

Main Methods:

• Development of an integrated mathematical model of the p53 network.
• Modeling encompasses p53 core regulation, p53-induced cell cycle arrest, and p53-dependent apoptosis initiation.
• Analysis of nuclear p53 dynamic profiles to understand differential pathway regulation.

Main Results:

• Different features of the nuclear p53 dynamic profile differentially regulate pro-survival and pro-death modules.
• Pro-survival pathway activation depends on the current or recent DNA damage status.
• Pro-death pathway activation relies on the integration of damage levels over time, acting as an "adaptive timer".

Conclusions:

• The p53 network employs an "adaptive timer" strategy to decide cell fate, where the duration of DNA damage influences the choice between survival and death.
• This adaptive timer strategy, inversely proportional to damage level, allows cells to initiate apoptosis if damage is irreparable within a specific timeframe.
• This regulatory strategy may be conserved across other cellular stress response systems.