Microtubules and cortical components are required for polarization. (A) Both nocodazole and C3 prevented the morphological changes associated with mitotic exit. Anillin localized to the cortex after mitotic exit in nocodazole but was not polarized. C3 blocked all evidence of polarization and also recruitment of Anillin to the cortex. (B) Monopolar HeLa cells were pretreated with latrunculin B or (−)-blebbistatin before purvalanol A addition. Boxed regions are magnified below. Some F-actin remained after latrunculin B treatment. Each local cluster of F-actin was associated with cytokinesis proteins but global polarization was blocked. Blebbistatin blocked global polarization but not recruitments of cytokinesis proteins to the cortex or microtubule tips. Bars, 5 μm.