Numb is a factor of cell fate determinant, which, by asymmetrically partitioning at mitosis, controls cell fate choices by antagonising the activity of the plasma membrance receptor of the Notch family. Numb has recently been shown to help activate the tumor suppressor protein p53. Loss of numb would result, therefore, in both the activation of the potential oncogene notch and the diminution of tumor suppression by p53. Here, we review the structure and function of Numb, Numb-related molecules and the relationship between Numb and tumor.
