| p53
in apoptosis |
|
|
|
|
|
|
|
| Following
DNA damage, e.g. by radiation, p53 levels rise, and |
||||||
| proliferating
cells arrest in G1. This allows time for DNA repair |
||||||
| prior
to the next round of replication. This arrest is mediated by |
||||||
| stimulation
of expression of p21CIP1, the cyclin kinase inhibitor. |
||||||
| Very
high p53 levels, or susceptible cell types, e.g. lymphocytes, |
||||||
| are
triggered to undergo apoptosis. Bcl-2 acts between p53 and the |
||||||
| caspase: |
||||||