FIGURE 5.

Diagram of Notch-dependent lateral inhibition of a cell fate decision. A: a small cluster of cells (peach) begins to differentiate in response to a local cue, such as a growth factor. B: expression of Notch and a Notch ligand [e.g., Delta-like 4 (Dll4) for an endothelial tip/stalk cell decision] increase until one cell, shown in green, reaches a threshold that can trigger Notch signaling in the adjacent, signal receiving cell (arrows). C: if Notch signaling is blocked, all peach-colored cells will acquire the default differentiation state (green). D: intact Notch signaling helps execute the proper cell fate decision in which a single green cell acquires one cell fate while the surrounding cells are prevented from acquiring the same fate through lateral inhibition. The change in color from peach to red indicates that Notch signaling can also promote further differentiation in the laterally inhibited cells.