Fig. 3

Schematic of the Wnt, MAPK, and PI3K-AKT-mTOR signaling pathways. The Wnt pathway is activated when Wnt proteins bind to Frizzled-LRP receptor complex composed of Frizzled and LRP resulting in translocation of β-catenin to the nucleus, ultimately targeting cell differentiation. The MAPK and PI3K-AKT pathways are initiated by the binding of various small proteins (growth factors, cytokines and insulin) to their respective receptor tyrosine kinase (RTK). The MAPK cascade results in translocation of the Erk1/2 complex to the nucleus and targets cell proliferation pathways, whereas the PI3K-AKT pathway results in mTOR activation and the regulation of protein synthesis. Green arrows indicate positive regulators, whereas red arrows indicate negative regulators