Grant: CIHR Fellowship

The Wnt signaling pathway is composed of a complex network of proteins including Wnt proteins, DKK and Frizzle-like domains. Wnts are characterized by a conserved pattern of 23 cysteines that are post-translationally palmitoylated. Wnt3A plays a central role in the embryonic development, cell migration, cell polarity, cell proliferation and cell fate specification along with its key role in various forms of cancer. The Wnt-signaling pathway involves several interaction profiles of Wnt with Frizzled (FZD) receptors causing the activation of Disheveled family proteins and ultimately affects the amount of beta-catenin release to nucleus. This signaling cascade has implications on many biological processes. In the proposed research program, I will investigate the structure-function relationship of the C-terminal domain of Wnt3A with its various interaction partners. From a functional perspective, it is the most important component in the Wnt-signaling pathway. We have already designed eukaryotic expression systems for high-quality preparations of Wnt3A and designed Wnt3A-FZD7 fusion protein systems. I aim to investigate their biophysical properties by employing analytical ultracentrifugation and light scattering methods. I further intent to determine the high-resolution structure using protein X-ray crystallography and solution NMR-techniques. This novel structural information at atomic level will provide new molecular details about the structure-function relationships of the Wnt-FZD interaction. In addition it will also help us to understand how this complex affects the Wnt-signaling pathway, a key signal transduction pathway in numerous biological processes.