In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Q: Co-activators of this protein include BRCA1. Discovered in 1979 by Crawford et al, mutations in this protein often lead to a high susceptibility of Li-Fraumeni Syndrome. After getting a ubiquitin attached to it, this protein is degraded unless USP7 interacts with it; that ubiquitin is placed on it by MDM2, which regulates this protein. This protein can be inactivated by E6, a mechanism that HPV uses. It is activated in response to stresses such as (*) UV rays, osmotic shock and deregulated oncogene expression. It stimulates another protein that binds to CDK2. Its functions include activating DNA repair proteins when DNA becomes damaged and initiating apoptosis of cells with damaged DNA. For 10 points, name this protein whose role as a cancer inhibitor leads it to be called the ""guardian angel"" of the cell and which is named for its molecular weight in kilodaltons.
A:
Science