NUMB and brain neoplasm: Basal cell fate determinants Numb, Prospero (Pros), Brain tumor (Brat), and their adaptor proteins Partner of Numb (Pon) and Miranda (Mira) are critical for neuronal differentiation upon asymmetric segregation into the differentiating daughter cell (Gonzalez, 2007; Doe, 2008; Knoblich, 2010).