Dynasore

Dynasore is a noncompetitive inhibitor of GTPases with the IC50 value of 15 μM[1] [2].
GTPases (singular GTPase) are hydrolase enzymes that play an important role in GTP binding and hydrolyzing. GTPases involve in many processes, like, transduction signal, protein biosynthesis, translocation proteins through membranes, and transporting vesicles within the cell. It has been reported that dynasore could inhibit the GTPase activity of dynamin1, dynamin2 and Drp1 [3] [4].
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 [1].  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[4]. Dynasore worked as inhibitor of dynamin GTPase activity which blocks dynamin-dependent endocytosis not only in cells, but also including neurons [3].
References:
[1].Zheng, J., et al., Chymase mediates injury and mitochondrial damage in cardiomyocytes during acute ischemia/reperfusion in the dog. PLoS One, 2014. 9(4): p. e94732.
[2].McCluskey, A., et al., Building a better dynasore: the dyngo compounds potently inhibit dynamin and endocytosis. Traffic, 2013. 14(12): p. 1272-89.
[3].Kirchhausen, T., E. Macia, and H.E. Pelish, Use of dynasore, the small molecule inhibitor of dynamin, in the regulation of endocytosis. Methods Enzymol, 2008. 438: p. 77-93.
[4].Newton, A.J., T. Kirchhausen, and V.N. Murthy, Inhibition of dynamin completely blocks compensatory synaptic vesicle endocytosis. Proc Natl Acad Sci U S A, 2006. 103(47): p. 17955-60.