Final answer:
p53 acts as a tumor suppressor by detecting and responding to DNA damage in cells. It can halt the cell cycle for DNA repair or induce apoptosis if damage is irreparable. p53's role is critical in preventing the division of cells with potential cancer-causing mutations.
Step-by-step explanation:
The protein p53 has a crucial role in controlling the cell cycle and maintaining the integrity of the genome within a cell. Its primary function is to act as a tumor suppressor, which means it works to prevent the propagation of damaged DNA that can lead to cancer. One of the ways p53 does this is by detecting DNA damage in cells. When damage is detected, p53 halts the cell cycle, either to allow time for DNA repair or, if the damage is irreparable, to initiate apoptosis (also known as programmed cell death).
If a cell encounters an anomaly, such as being improperly stimulated by a hormone, p53 can prevent unregulated cell division by either allowing the cell to repair itself or inducing apoptosis, thereby preventing the potential formation of cancerous cells. Furthermore, p53 works at the G1 checkpoint of the cell cycle, where p21 is activated to inhibit other proteins that normally advance the cell cycle, further ensuring that cells with damaged DNA do not continue to divide. In contrast, cells with a mutated p53 gene can behave as though there is no DNA damage present, allowing division to proceed and potentially leading to the spread of the mutation and cancer development.