Designing and developing tools to probe, monitor, and modulate the Wnt signaling pathway

Abstract

A combined theoretical and computational model was proposed to elucidate the fundamental mechanism of the Wnt/beta-catenin signaling pathway. Analysis suggested that the partial inhibition of both beta-catenin phosphorylation and ubiquitination results in an increase in cytosolic concentration of beta-catenin. The inhibition of these post-translational modification steps stems from the partial disassembly of a fraction of the intracellular destruction complexes, and this disassembly is correlated with these destruction complexes relocating to the plasma membrane upon Wnt stimulation. The understanding of the Wnt/beta-catenin pathway was leveraged to design a synthetic dimeric activator of the canonical Wnt signaling pathway, with levels of activation comparable to that of wild-type Wnt-3a. Next, a toolbox of novel optogenetic photoswitches, with tunable dissociation dynamics, was designed by engineering the canonical Wnt protein, LRP6. Finally, transcription-activation based switches were proposed to determine different cell specifications in order to ensure high quality of cardiomyocyte production from human pluripotent stem cells (hPSCs). Taken together, the work discussed in this thesis can serve as a platform for future investigations into several developmental pathways.