Figure 3.

Variants of the Notch-Wnt crosstalk. (a) Co-operative and synergistic regulation of gene transcription when both pathways are active. (b) Sequential signaling is initiated when one active pathway promotes transcription of the ligand of the other pathway (top: active Notch signaling promotes expression of Wnt ligands; below: active Wnt signaling promotes expression of Notch ligands). (c) Examples of direct molecular crosstalk (top: both pathways are activated, but β-catenin is inhibited by NICD (inhibitory crosstalk); below: the Notch pathway is activated and co-activates intracellularly the Wnt cascade (activating crosstalk).