Paclitaxel-dependent mutant Tax 11-6 has a mutation in alpha-tubulin that disrupts microtubule assembly, prevents cytokinesis, and leads to cells that are large and multinucleated. Live cell imaging showed that the disrupted cytoskeleton arose from an increased frequency of microtubule detachment from centrosomes and spindle poles. The presence of paclitaxel prevented microtubule detachment and allowed proliferation as normal diploid cells. For details, see the article by Ganguly and colleagues on page 2914.