FIGURE 4.

Microtubule detachment from centrosomes. A, HAβ3-3 cells were transfected with GFP-MAP4, and live cell images of fluorescent microtubules were recorded every 5 s. The asterisks indicate the position of the centrosome. The arrowheads mark the position of the minus-end of a microtubule that was seen detaching from the centrosome. Scale bar = 10 μm. B, quantification of the frequency of microtubule detachment per cell per min in WT cells and in paclitaxel-dependent cells (Tax 11-6 and HAβ3-3) transfected with the empty vector (open bars) or with a vector producing shRNA to MCAK and then selected in hygromycin to enrich for cells harboring plasmid DNA (filled bars). ***, p < 0.0001. There was no statistically significant difference in detachment rates between WT and mutant cell lines following depletion of MCAK (filled bars).