Is p53 a caspase?
The p53 tumor suppressor gene is critically involved in cell cycle regulation, DNA repair, and programmed cell death. Several lines of evidence suggest that p53 death signals lead to caspase activation; however, the mechanism of caspase activation by p53 still is unclear.
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.
What are the mechanisms and functions of apoptosis?
apoptosis, also called programmed cell death, in biology, a mechanism that allows cells to self-destruct when stimulated by the appropriate trigger. Apoptosis can be triggered by mild cellular injury and by various factors internal or external to the cell; the damaged cells are then disposed of in an orderly fashion.
What is p53-dependent pathway?
p53-regulated genes encoding mitochondrial proteins The Bax gene promoter contains a p53-binding site and was shown to be p53 responsive. 23. The proapoptotic Bax protein is known to accumulate in mitochondria in response to death signals. Noxa mRNA is induced by ionizing radiation in a p53-dependent manner.
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.
