The protein that inhibits p53 is MDM2 (also known as HDM2).
MDM2 acts as a ubiquitin ligase, marking p53 for degradation by the proteasome. This process helps regulate the levels of p53 in the cell, ensuring that it is only active when necessary.
MDM2 directly binds to the N-terminal transactivation domain of p53, blocking its ability to activate target genes. This interaction is crucial for maintaining cellular homeostasis, preventing the uncontrolled activation of p53, and protecting against unwanted apoptosis.
The MDM2-p53 interaction is a complex and tightly regulated process. Several other proteins can influence this interaction, including:
- p14ARF: This protein binds to MDM2, preventing it from interacting with p53 and thereby promoting p53 activation.
- p19ARF: Similar to p14ARF, p19ARF inhibits MDM2's ability to bind and degrade p53.
The interplay between p53 and MDM2 is crucial for maintaining cellular health and preventing uncontrolled cell growth. Disruptions in this interaction can lead to various diseases, including cancer.
