16 Questions
What is the main function of p53?
Activating and repressing target genes implicated in cell cycle control
How does p53 respond to DNA damage?
Activates DNA repair proteins
What is the significance of p53 mutations in human cancers?
They are found in up to 50% of human cancers
Which signaling pathways convey signals modifying activities of p53?
Multiple signaling pathways
What is the role of p53 in preventing abnormal cell selection?
Ensuring genetic identity of cells
How does p53 contribute to cancer prevention?
Inducing apoptosis if DNA damage proves to be irreparable
Which protein has long been known to be a cellular sensor for DNA damage?
p53
What is the main reason p53 has been dubbed the guardian of the genome?
Its ability to induce cell cycle arrest
Which genes were discovered almost 20 years after the discovery of p53?
p63 and p73
What is the relationship between p63, p73, and p53 in terms of their homology?
p63 and p73 are more homologous to each other than to p53
What is the function of MDM-2 in response to an increase in p53 activity?
It acts as an E-3 ubiquitin ligase that adds ubiquitin to p53, resulting in its degradation
What is the role of MDM-X in response to MDM-2 oligomerization?
It stabilizes MDM-2 and inhibits its degradation
What cellular stress signals appear to activate p53?
$Ƴ$-irradiation and genotoxic drugs
What is the role of CHK2 in response to single or double stranded breaks in DNA?
It delays or reduces p53 activation
What is the function of ATM in response to UV irradiation?
It delays or reduces p53 activation
Which proteins are products of a p53-activated gene?
MDM-2 and MDM-X
Study Notes
p53 Function and Regulation
- The main function of p53 is to respond to DNA damage and prevent abnormal cell selection and cancer.
- p53 responds to DNA damage by converging signals from multiple signaling pathways, including ATM and CHK2.
- Signaling pathways that convey signals modifying p53 activities include ATM, CHK2, and MDM-2.
p53 Mutations and Cancer
- p53 mutations are significant in human cancers, as they can lead to uncontrolled cell growth and tumorigenesis.
- p53 mutations are often found in more than 50% of human cancers.
p53 as the Guardian of the Genome
- p53 is dubbed the guardian of the genome due to its crucial role in maintaining genomic stability and preventing cancer.
- p53 responds to DNA damage by inducing cell cycle arrest, apoptosis, or DNA repair.
p53 Family and Homologs
- p63 and p73 are homologs of p53, sharing similar structures and functions.
- p63 and p73 are also tumor suppressors, but with some distinct functions compared to p53.
p53 Regulation and Interaction
- MDM-2 regulates p53 activity by binding and inhibiting its transcriptional activity.
- MDM-X regulates MDM-2 oligomerization and p53 activity.
- p53 is activated in response to various cellular stress signals, including DNA damage, hypoxia, and oncogene activation.
p53-Mediated Signaling and Cancer Prevention
- p53 contributes to cancer prevention by inducing cell cycle arrest, apoptosis, or DNA repair in response to DNA damage.
- The CHK2 protein is activated in response to single or double-stranded breaks in DNA, and phosphorylates p53 to activate its function.
- ATM is activated in response to UV irradiation and phosphorylates p53 to activate its function.
- The products of p53-activated genes, such as p21 and BAX, also contribute to cancer prevention.
Test your knowledge about the p53 tumor suppressor protein and its encoding gene TP53. Learn about its role as a transcription factor and its significance in tumor development.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
