English: Microtubule destabilizing effect of IC261 in mitotic cells. CV-1 cells expressing EYFP-tubulin were cultured in a flow-through chamber and observed by time-resolved fluorescence microscopy. At time point “0 min” cells were treated with DMSO (0.125%), 50 µM IC261 and/or 10 µM taxol. Here exemplary cells are shown for indicated time points. Treatment with 50 µM IC261 induced the complete depolymerization of microtubules within a few minutes (3–5 min). When cells were treated with 10 µM taxol during time period “−10 min” to “0 min” prior to treatment with taxol+IC261 at time point “0 min” the MT depolymerizing effect of IC261 could be blocked. When cells were first treated for 10 min with IC261 resulting in a complete dissolution of the spindle apparatus, and subsequently treated with taxol+IC261 tubulin could re-polymerize at the spindle poles and in other MT nucleation centers within the cell.