Figure 4.

Mechanisms of Notch signaling regulation. (A) Following Notch activation, bi-directional Notch signaling can be initiated in both source and target cells. Cleavage of the intracellular domain of both Notch receptor and ligand can occur. These cleaved proteins translocate into the nucleus of their respective cells to function as transcription factors. (B) Notch activation in target cells can result in expression of Notch ligand. Such cells can subsequently function as source cells to activate Notch signaling in neighboring cells. This phenomenon is termed lateral induction. (C) Canonical Notch signaling can be blocked through cis-inhibition. This occurs when interaction of Notch receptor and ligand on the same target cell impedes the traditional trans-interaction of the ligand-expressing source cell with the target cell’s Notch receptor. CBF1: C-promoter binding factor 1 (also termed RBPjκ).