P53

p53 is a protein that in humans is encoded by the TP53 gene. The p53 protein is crucial for preventing cancer, as it is a tumor suppressor. It is important for cells in multicellular organisms to suppress cancer. p53 has been described as "the guardian of the genome" because of its role in conserving stability by preventing genome mutation.

Function

p53 has many mechanisms of anticancer function, and plays a role in apoptosis, genomic stability, and inhibition of angiogenesis. In its anti-cancer role, p53 works through several mechanisms:

• It can activate DNA repair proteins when DNA has sustained damage.
• It can induce growth arrest by holding the cell cycle at the G1/S regulation point on DNA damage recognition.
• It can initiate apoptosis, the programmed cell death, if the DNA damage proves to be irreparable.

Regulation

p53 is a short-lived protein and its activity is also regulated by post-translational modification and by protein-protein interaction. The ubiquitin ligase Mdm2 (also called HDM2 in humans) is a major regulator of p53, by mediating its degradation.

Clinical significance

Mutations in the p53 gene leading to conformational changes in the p53 protein are common in human cancers. In fact, p53 mutations occur in almost every type of cancer, at a frequency of 10% to 100%, depending on the type of cancer.

See also

• TP53
• Tumor suppressor
• Cancer
• Genome
• DNA repair
• Cell cycle
• Apoptosis
• Angiogenesis

References

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