GSK3 Inhibits Macropinocytosis and Lysosomal Activity through the Wnt Destruction Complex Machinery

Albrecht et al. show that macropinocytosis is triggered by GSK3 inhibition or mutation of the tumor suppressor Axin1. Wnt-regulated macropinocytosis leads to acidification and activation of catabolism in lysosomes, increasing the utilization of extracellular macromolecules to fuel cell growth. These findings have implications for novel therapies in cancer.