What does the tumor suppressor p53 gene do?

What does the tumor suppressor p53 gene do?

Normal Function The TP53 gene provides instructions for making a protein called tumor protein p53 (or p53). This protein acts as a tumor suppressor, which means that it regulates cell division by keeping cells from growing and dividing (proliferating) too fast or in an uncontrolled way.

How is p53 tumor suppressor regulated?

The activation of p53 by ARF is auto-regulated by a feedback loop. p53 down-regulates the expression of ARF by directly suppressing its promoter69 and by blocking E2F-1 activation, which induces ARF expression. ARF activates p53 by neutralizing Mdm2-mediated ubiquitination and degradation of p53.

Is p53 a tumor suppressor protein?

The p53 gene like the Rb gene, is a tumor suppressor gene, i.e., its activity stops the formation of tumors. If a person inherits only one functional copy of the p53 gene from their parents, they are predisposed to cancer and usually develop several independent tumors in a variety of tissues in early adulthood.

What is the function of p53 and why is it the most common mutation in cancerous tumor cells?

P53 is often mutated in solid tumors, in fact, somatic changes involving the gene encoding for p53 (TP53) have been discovered in more than 50% of human malignancies. P53 is a transcription factor able to regulate several intracellular pathways involved in cell survival, DNA-repair, apoptosis and senescence.

How does p53 regulate the cell cycle?

P53 induces cell cycle arrest In response to various cellular stress, P53 can activate the transcriptional upregulation of CDKN1A, which encodes for cell cycle inhibitor P21 [30]. P53 can also activate other genes like GADD45A, which also contributes to cell cycle arrest [31].

What is the role of the p53 protein in the cell cycle in normal cells?

In normal cells, the p53 protein level is low. DNA damage and other stress signals may trigger the increase of p53 proteins, which have three major functions: growth arrest, DNA repair and apoptosis (cell death). The growth arrest stops the progression of cell cycle, preventing replication of damaged DNA.

What is the role of p53 in the cell cycle?

It controls several genes that play a role in the arrest of the cell cycle, cellular senescence, DNA repair system, and apoptosis. P53 plays a crucial role in supporting DNA repair by arresting the cell cycle to purchase time for the repair system to restore genome stability.

What kind of protein is p53?

p53 is a nuclear transcription factor with a pro-apoptotic function. Since over 50% of human cancers carry loss of function mutations in p53 gene, p53 has been considered to be one of the classical type tumor suppressors. Mutant p53 acts as the dominant-negative inhibitor toward wild-type p53.

Where does p53 stop the cell cycle?

Activated p53 can halt cell division in both the G1 and G2 phases of the cell division cycle. G1 is the preparation phase of the cell before replication of its DNA and G2 prepares the cell for mitosis.

What genes does p53 regulate?

p53 is a transcriptional activator, regulating the expression of Mdm2 (for its own regulation) and the genes involved in growth arrest, DNA repair and apoptosis.

How do Tumour suppressor genes work?

Tumor suppressor genes represent the opposite side of cell growth control, normally acting to inhibit cell proliferation and tumor development. In many tumors, these genes are lost or inactivated, thereby removing negative regulators of cell proliferation and contributing to the abnormal proliferation of tumor cells.