Dynasore

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%. ^[1]

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. ^[2]

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. ^[3]

• GTPase activity assay

  GTPase activity is measured by using a radioactive charcoal-based assay. Proteins dynamin, human Drp1 at the indicated concentrations are incubated in 10 mM Tris (pH 7.2), 2 mM MgCl₂, and 20 μM GTPγP³² (2000 dpm/pmol) alone or, when appropriate, with lipid nanotubes for the indicated times and temperatures; the final NaCl concentration is 150 mM NaCl for the high-salt condition and between 10 and 20 mM for the low-salt conditions depending on the protein concentration in the stock solution. GTP hydrolysis is ended by transferring 10 μL aliquots of the reaction into a 500 μL slurry containing acid-washed charcoal, followed by a 10 min centrifugation (20000 × g, 4 ℃) and final counting of the liberated P³²O₄ contained in 250 μL supernatant.

• Animal Models

  Female Sprague–Dawley rats

• Dosages

  1, 10, or 30 mg/kg

• Administration

  i.p.