YAP/TAZ incorporation in the β-catenin destruction complex orchestrates the Wnt response

Area of Science:

• Cell Biology
• Molecular Biology
• Developmental Biology

Background:

• The Hippo pathway transducers YAP/TAZ have complex roles in Wnt signaling.
• Mechanisms linking YAP/TAZ and Wnt signaling are not fully understood.

Purpose of the Study:

• To elucidate the molecular mechanisms by which YAP/TAZ interact with and regulate Wnt signaling.
• To investigate the role of YAP/TAZ in the β-catenin destruction complex.

Main Methods:

• Biochemical assays to assess protein interactions.
• Functional studies in cell lines.
• Genetic analyses in relevant models.
• Ex vivo crypt regeneration assays.

Main Results:

• YAP and TAZ are integral components of the β-catenin destruction complex, acting as a cytoplasmic sink.
• In Wnt-ON cells, YAP/TAZ are released from the complex, enabling nuclear accumulation and Wnt/YAP/TAZ signaling.
• YAP/TAZ are essential for APC deficiency-induced intestinal crypt overgrowth and ex vivo crypt regeneration.
• In Wnt-OFF cells, YAP/TAZ facilitate β-TrCP recruitment and β-catenin inactivation.
• Loss of YAP/TAZ sustains the β-catenin-dependent maintenance of undifferentiated embryonic stem cells.

Conclusions:

• YAP/TAZ function as key regulators within the β-catenin destruction complex, bridging Hippo and Wnt pathways.
• This interaction framework is critical for controlling organ size, regeneration processes, and tumor suppression.
• The dynamic interplay between YAP/TAZ and the destruction complex offers new insights into developmental and disease mechanisms.