Figure 1.

Nuclear β‐catenin is the hallmark of canonical Wnt signaling. Diagram depicting two cells and an outline of the canonical Wnt signal transduction pathway. (a) In a cell that is not responding to extracellular Wnt signaling any cytoplasmic β‐catenin protein is proteolytically degraded. (b) In response to extracellular Wnt signaling, any cytoplasmic β‐catenin protein is stabilized and enters the nucleus to regulate Wnt target gene expression in a complex with DNA‐binding transcription factors. For a more detailed recent review of Wnt signaling mechanisms, consult Hoppler and Nakamura (2014)