The human homologue of Drosophila numb (mammalian numb, mNumb, 603 aa) is a membrane-associated protein that predominantly segregates to only one of the daughter cells of a dividing neural precursor and has an important role in neural development, by a signalling pathway that antagonizes the Notch pathway. There are multiple splicing isoforms. Numb also blocks the ubiquitination and degradation of p53, and Numb-defective breast tumours have a poor prognosis. The cytoplasmic ligands of Numb are the PDZ domain-containing ring finger proteins 1 and 2 (632 aa), E3 ligases involved in ubiquitination.
Subjects: Medicine and Health.