ELR510444 causes loss of cellular microtubules. A, A-10 cells were treated with vehicle (DMSO), 12.5 nM CA-4, or 50 nM ELR510444 for 18 h. Microtubules were visualized by indirect immunofluorescence for β-tubulin. The loss of cellular microtubules can be seen in CA-4- and ELR510444-treated cells. B, the percent microtubule depolymerization observed at each concentration of ELR510444 was estimated visually, the effects of a range of concentrations were plotted, and the EC50 value of 21 nM was calculated from linear regression analysis.