In vitro activity: Dynasore acts as a potent inhibitor of endocytic pathways known to depend on dynamin by rapidly blocking coated vesicle formation within seconds of dynasore addition. Two types of coated pit intermediates accumulate during dynasore treatment, U-shaped, half formed pits and O-shaped, fully formed pits, captured while pinching off. Dynasore at concentration of 80 μM, also inhibits the enzymatic activity of the mitochondrial dynamin Drp1. Dynasore strongly blocks the uptake, trafficking, and intracellular accumulation of transferrin in HeLa cells with IC50 of ~15 μM. Dynasore also prevents the endocytosis of low-density lipoprotein and cholera toxin. Dynasore (80 μM) strongly interferes with the spread of freshly plated cells, and inhibits BSC1 cells migration by about 50%. Dynasore completely and reversibly blocks endocytosis in cultured hippocampal neurons after sustained or brief action potentials stimuli with full inhibition at 80 μM and a half-maximal inhibition at ~30 μM. In the presence of Dynasore, low-frequency stimulation leads to sustained accumulation of synaptopHluorin and other vesicular proteins on the surface membrane at a rate predicted from net exocytosis, as well as a reduction in the density of synaptic vesicles and the presence of endocytic structures only at synapses. Dynasore can block human epithelial cell HEK 293 infection of human papillomavirus type 16 and bovine papillomavirus type 1 pseudovirions with equal IC50 of ~80 μM, which is partly reversible.

Cell Assay: Dynasore is a potent GTPases inhibitor and functions on the sites of dynamin1, dynamin2 or Drp1. When tested with HL-1 cells, treated cells with dynasore blocked the endocytic process via inhibiting the activity of dynamin. Using genetically encoded pH-sensitive fluorescent probe synaptopHluorin to study the role of dynasore in the synapses expressing spH, and the results showed that dyansore treatment resulted in the normal stimulus-triggered increase in fluorescence intensity via reducing the GTPase activity of dynamin which in turn blocked the synaptic endocytosis. Dynasore worked as inhibitor of dynamin GTPase activity which blocks dynamin-dependent endocytosis not only in cells, but also including neurons.

Dev Cell. 2006 Jun;10(6):839-50; Dev Cell. 2006 Jun;10(6):839-50.