It can activate DNA repair proteins when DNA has sustained damage. Thus, it may be an important factor in aging.[30]
It can arrest growth by holding the cell cycle at the G1/S regulation point on DNA damage recognition (if it holds the cell here for long enough, the DNA repair proteins will have time to fix the damage and the cell will be allowed to continue the cell cycle).
It can initiate apoptosis (i.e., programmed cell death) if DNA damage proves to be irreparable.