Question

Cell Signaling Pathways A Case Study Approach L. Emtage, L Bradbury, N. Coleman, D. Davenport. A Dunning and Grew Assignment. The Wnt/f-catenin pathway B-catenin B-catenin TO Note: GSK3, APC and Axin together are called the B-catenin Destruction Complex DSH is the abbreviation for Dishevelled. The human genome encodes many Fzd receptors, several Dsh proteins, one GSK3, and one ß-catenin. Questions 1. What are the components of the receptor complex? What is the ligand? 2. What is the molecular function of B-catenin itself? 3. Where is B-catenin found within the cell? Does its subcellular location ever change? 4. What are the molecular functions of GSK3, APC, and Axin? 5. Describe the ultimate outcome of Wnt pathway activation 6. Give two examples of negative regulation found here. Contrast their molecular mechanisms 7. Describe the effect of loss-of-function mutations in Frizzled, DSH, GSK3, and B- catenin separately on the transcription of target genes. You can assume that mutations in any part of the B-catenin Destruction Complex will cause the loss of function of the entire complex. 8. What role would Notum play in this pathway? 9. What modifications are made to the Wnt ligand prior to secretion from the cell and what interaction, once secreted, is it important for?

Answer 1

Ans. 1) receptor complex consist of three parts viz first one is ligand binding domain or signal binding domain second is transmembrane receptor and third one is activator domain which actually activate the intracellular signal molecules. And ligand act as a signaling molecule bind to another one.is the ion or molecule.

Ans.2) beta catenin is a multifunctional protein that binds to the e cadherin and connects actin filament to the alpha cadherin and form cytoskeleton.also it stabilize the nucleus in wnt pathway where it associate with the coactivator of T cell.

3) It is found in the cell cytoplasm.