FIG. 9.

Diagram illustrating proposed VRK1 action on p53. Two types of cycles can regulate p53 functions. One of the cycles is operational under normal proliferation conditions (blue box), where the damage is occasional and minimal and not enough to trigger a full p53 stress response. VRK1 somehow regulates proliferation and might be involved in p53 basal stabilization during normal proliferation. In response to severe or catastrophic damage (red box), like that induced by radiation, chemotherapy, or severe failure of DNA replication, p53 is fully activated and triggers a complete p53 response. Well-known kinases, such as ATM and ATR, are implicated in this p53 activation.