Dyngo-4a inhibits dynamin-dependent endocytosis of transferrin in multiple cell types with IC₅₀ of 5.7 μM, and reduces synaptic vesicle endocytosis and activity-dependent bulk endocytosis in cultured neurons and synaptosomes. In motor nerve terminals and cultured hippocampal neurons, Dyngo-4a blocks Alexa Fluor 488-BoNT/A-Hc internalization. In Drosophila S2R+ cells, Dyngo-4a causes a decrease in the level of Armadillo/β-catenin.