Notch signaling within and between cells is involved in many processes, including cell fate specification. In the retina, high levels of Notch during retinal progenitor cell (RPC) division promote RPC renewal, whereas low levels promote postmitotic neuron differentiation. Ha et al. found that retinal pigment epithelium (RPE), a neighboring tissue to the neural retina, influences asymmetric division by localizing Notch components to the apical side of the adjacent dividing RPC. This positioning required an E3 ubiquitin protein ligase, Mib1, which boosts levels of Notch in one sister cell, but not the other. Hence, a neighboring tissue influenced cell-fate specification through Notch signaling, which could also happen in other neural tissues.
Cell Rep. 10.1016/j.celrep.2017.03.040 (2017).