Drugs that affect microtubule dynamics are among the most effective anticancer agents in routine clinical use. The standard assay for antimicrotubule agents observes the ability of a particular substance to affect in vitro microtubule assembly. We have modified these procedures so that they can be performed in 96-well plates using a standard fluorescence plate reader. Two different protocols are provided in this chapter. One of these protocols is for ligands that inhibit microtubule polymerization, such as colchicine and related molecules. The second is for ligands that promote in vitro microtubule assembly, such as Taxol.
