Senescence And Apoptosis

Growth Arrest Cellular Senescence Apoptosis

Fig.15.3 A model for p53 transcriptional activation. (A) DNA damage signaling causes Mdm2-p53 disassociation and post-translational events leading to p53 activation. (B) The cell chooses a particular cell fate through known and unknown mechanisms. (C) If the DNA repair is not complete or is not repairable, the cell may choose G1 arrest, apoptosis, or cellular senescence as a fate. (D) On the other hand, if DNA repair is complete the cell may choose to re-enter the cell cycle through recruitment of Sir2a and/or PID/HDAC1 to deacetylate p53 and shut down p53-dependent transcription. (E) p53 is then regulated at low levels by Mdm2 until the next DNA damage event.

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