How does p53 induce apoptosis?
P53 induces apoptosis in nontransformed cells mostly by direct transcriptional activation of the pro-apoptotic BH3-only proteins PUMA and (to a lesser extent) NOXA. Combined loss of the p53 effectors of apoptosis (PUMA plus NOXA) and cell cycle arrest/cell senescence (p21) does not cause spontaneous tumour development.
Does the p53 gene start apoptosis?
Tumor protein p53 is a nuclear transcription factor that regulates the expression of a wide variety of genes involved in apoptosis, growth arrest, or senescence in response to genotoxic or cellular stress.
Is p53 pro or anti apoptotic?
Intriguingly, p53 was recently demonstrated to positively regulate expression of genes whose products are directly involved in both systems and owing to this, p53 clearly acts in an anti-apoptotic manner.
Does p53 activate Bcl 2?
p53 may also directly impact Bcl-2 activity as part of a transcription-independent program of cell death. In this process, cytoplasmic p53 binds to proapoptotic Bcl-2-family proteins, leading to permeabilization of mitochondria and apoptosis.
How is p53 mutated?
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 and several data confirmed that p53 mutations represent an early event in cancerogenesis.
What can induce apoptosis?
In cell lines intrinsic apoptosis can be induced by stimuli including removing growth factor supplements from cell media, exposure to UV light or by exerting other stressful conditions on the cell as shown on the left of Figure 1.
How p53 helps in cell cycle progression and apoptosis?
Cell-cycle arrest and apoptosis are the most prominent outcomes of p53 activation. Many studies showed that p53 cell-cycle and apoptosis functions are important for preventing tumor development. p53 also regulates many cellular processes including metabolism, antioxidant response, and DNA repair.
What genes promote apoptosis?
P53 gene. The tumor suppressor gene p53 is a gene with a key role in apoptosis. The protein it codes for belongs to a family of proteins that has three members: P53, P63 and P73.
What is p53 independent apoptosis?
The p53 gene encodes a transcription factor that can regulate cell proliferation and survival by modulating transcription of downstream target genes, inducing either G1 arrest or apoptosis (1, 10–13). p53 is activated to promote G1 arrest or apoptosis by several stimuli, the most well characterized being DNA damage.
Can apoptosis occur without p53?
p53-independent apoptosis may be able to compensate in the absence of p53 function to eliminate aneuploid cells, while p53-dependent apoptosis may play a more critical role in eliminating cells with genetic damage that is not associated with aneuploidy.
What will happen if p53 mutates?
This altered p53 protein cannot regulate cell growth and division and is unable to trigger apoptosis in cells with mutated or damaged DNA. As a result, DNA damage can accumulate in cells. If such cells continue to divide in an uncontrolled way, they can lead to the formation of bladder cancer.