This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'What is the half-life of p53 protein in normal cells? \nSelect and explain. \nA. 20 minutes, B. 60 minutes, C. 12 hours, D. 1 day', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In non stressed, healthy cells, p53 has a sho half-life (20 minutes), because of its association with MDM2, a protein that targets it for destruction. When the cell is stressed, for example by an assault on its DNA, p53 undergoes post-transcriptional modifications that release it from MDM2 and increase its half-life. Unshackled from MDM2, p53 also becomes activated as a transcription factor. Ref: Robbins 8th edition Chapter 7.', 'role': 'assistant'}]