Figure 9.

A model depicting the roles of Notch signaling pathways in governing the transition from proliferation to differentiation in epidermal progenitors. Upon ligand engagement, Notch is activated, releasing NICD. NICD plays two roles in driving the transition from basal to spinous cells. NICD interacts with RBP-J to drive expression of Hes1, a canonical target gene. This leads to the downstream induction of spinous layer genes encoding differentiation-specific proteins. NICD represses basal genes including integrins, allowing basal cells to detach from the BL during stratification by a mechanism independent of Hes1.