p53, also known as Tumor protein P53, cellular tumor antigen p53, or transformation-related protein 53 (TRP53) is a regulatory protein that is often mutated in human cancers. The p53 proteins are crucial in vertebrates, where they prevent cancer formation. As such, p53 has been described as "the guardian of the genome" because of its role in conserving stability by preventing genome mutation. Hence TP53 is classified as a tumor suppressor gene.
p53 pathway: In a normal cell, p53 is inactivated by its negative regulator, mdm2. Upon DNA damage or other stresses, various pathways will lead to the dissociation of the p53 and mdm2 complex. Once activated, p53 will induce a cell cycle arrest to allow either repair and survival of the cell or apoptosis to discard the damaged cell. How p53 makes this choice is currently unknown.
A micrograph showing cells with abnormal p53 expression (brown) in a brain tumor. p53 immunostain.
A schematic of the known protein domains in p53. (NLS = Nuclear Localization Signal).
Chromosome 17 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 17 spans more than 84 million base pairs and represents between 2.5 and 3% of the total DNA in cells.
Inactivating PH mutation in either the EVER1 or EVER2 genes, which are located adjacent to one another on chromosome 17 causes Epidermodysplasia verruciformis.
