The p53 protein is well-known for its tumour suppressor function. The
p53-MDM2 negative feedback loop constitutes the core module of a network of
regulatory interactions activated under cellular stress. In normal cells, the
level of p53 proteins is kept low by MDM2, i.e. MDM2 negatively regulates the
activity of p53. In the case of DNA damage,the p53-mediated pathways are
activated leading to cell cycle arrest and repair of the DNA. If repair is not
possible due to excessive damage, the p53-mediated apoptotic pathway is
activated bringing about cell death. In this paper, we give an overview of our
studies on the p53-MDM2 module and the associated pathways from a systems
biology perspective. We discuss a number of key predictions, related to some
specific aspects of cell cycle arrest and cell death, which could be tested in
experiments