How does p53 regulate 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.
What is p53 and what role does it play in cancer?
p53, also known as TP53 or tumor protein (EC :2.7. 1.37) is a gene that codes for a protein that regulates the cell cycle and hence functions as a tumor suppression. It is very important for cells in multicellular organisms to suppress cancer.
Is p53 necessary for apoptosis?
One of the most important p53 functions is its ability to activate apoptosis, and disruption of this process can promote tumor progression and chemoresistance.
What is regulated by p53?
The tumour suppressor p53 has a central role in the response to cellular stress. Activated p53 transcriptionally regulates hundreds of genes that are involved in multiple biological processes, including in DNA damage repair, cell cycle arrest, apoptosis and senescence.
What is p53 dependent apoptosis?
The p53 tumor suppressor limits cellular proliferation by inducing cell cycle arrest and apoptosis in response to cellular stresses such as DNA damage, hypoxia, and oncogene activation. Many apoptosis-related genes that are transcriptionally regulated by p53 have been identified.
How is apoptosis controlled?
The intracellular cell death program is also regulated by extracellular signals, which can either activate apoptosis or inhibit it. These signal molecules mainly act by regulating the levels or activity of members of the Bcl-2 and IAP families.
What is p53 and why does a loss of function mutation at p53 leads to cancer or uncontrolled cell growth?
In most cases, the p53 gene is mutated, giving rise to a stable mutant protein whose accumulation is regarded as a hallmark of cancer cells. Mutant p53 proteins not only lose their tumor suppressive activities but often gain additional oncogenic functions that endow cells with growth and survival advantages.
Does p53 bind to a promoter?
p53 overrides epigenetic regulatory landscapes to bind a common set of enhancers in a variety of cellular contexts. The overall output of the p53 transcriptional program is strongly qualified by cellular context via enhancer licensing, core promoter responsiveness, and chromatin architecture.
Is p53 a positive regulator?
It has been reported recently that the wild-type p53 gene product can positively regulate the expression of a test gene adjacent to the enhancer-promoter elements of the murine muscle-specific creatine kinase (MCK) gene.
What is TP53-inducible glycolysis and apoptosis regulator?
The TP53-inducible glycolysis and apoptosis regulator (TIGAR) also known as fructose-2,6-bisphosphatase TIGAR is an enzyme that in humans is encoded by the C12orf5 gene. TIGAR is a recently discovered enzyme that primarily functions as a regulator of glucose breakdown in human cells.
Is there a p53-inducible gene?
The p53 tumor-suppressor protein prevents cancer development through various mechanisms, including the induction of cell-cycle arrest, apoptosis, and the maintenance of genome stability. We have identified a p53-inducible gene named TIGAR (TP53-induced glycolysis and apoptosis regulator).
What is the p53 tumor-suppressor protein?
The p53 tumor-suppressor protein prevents cancer development through various mechanisms, including the induction of cell-cycle arrest, apoptosis, and the maintenance of genome stability. We have identified a p53-inducible gene named TIGAR ( T P53- i nduced g lycolysis and a poptosis regulator).
What is the role of p53 in cell cycle?
Under high levels of cellular stress, p53 initiates apoptosis instead. In non-resting cells, the cell cycle consists of G0 -> G1 -> S -> G2 -> M phases, and is tightly regulated at checkpoints between the phases.