Jerky/Earthbound facilitates cell-specific Wnt/Wingless signalling by modulating β-catenin-TCF activity

Area of Science:

• Cell Biology
• Developmental Biology
• Molecular Biology

Background:

• Wnt/Wingless signaling is vital for development but its hyperactivation causes colorectal cancer.
• Cell-specific responses to Wnt signaling are not fully understood.
• Understanding how cell context influences Wnt signaling outcomes is crucial.

Purpose of the Study:

• To identify novel components that modulate Wingless signaling.
• To investigate the role of Earthbound 1 (Ebd1) in Wnt pathway regulation.
• To explore the functional relationship between Ebd1 and human Jerky protein.

Main Methods:

• Conducted a Drosophila genetic screen to identify Wingless signaling enhancers.
• Utilized protein interaction studies to examine Ebd1/Jerky and Wnt pathway components.
• Performed functional assays in colon carcinoma cells to assess Jerky's role in Wnt signaling.

Main Results:

• Identified Earthbound 1 (Ebd1), a novel protein with Centromere Binding Protein B (CENPB)-type DNA binding domains.
• Ebd1 is expressed in specific cell types and regulates a subset of Wingless-dependent processes.
• Human Jerky protein functionally replaces Ebd1 and interacts with β-catenin/Armadillo and T-cell factor (TCF).
• Jerky promotes Wnt signaling in colon cancer cells by enhancing β-catenin/TCF association and chromatin recruitment.

Conclusions:

• Tissue-restricted transcriptional co-activators, like Ebd1 and Jerky, fine-tune cell-specific Wnt/Wingless signaling.
• These co-activators modulate β-catenin-TCF activity, influencing developmental processes and disease.
• Findings provide insights into the molecular mechanisms underlying cell-specific Wnt pathway regulation.