Mitotic rounding of epithelial cells is accompanied by an increase in cortical myosin. (A) Representative image of MDCK cells expressing GFP–myosin IIA in interphase and following entry in mitosis (Video 7). (B) Quantification of the ratio of cortical versus cytosolic GFP–myosin IIA in MDCK cells in interphase and following entry in mitosis (n = 30). Data were pooled from three independent experiments. ****, P < 0.0001; paired t test. (C) Representative image (z-projection) of immunostaining of MDCK cells for phospho-S19 myosin IIA, together with DAPI, showing an increase in myosin IIA phosphorylation upon mitotic entry. All scale bars, 10 μm. t, time.