MKlp2 promotes and maintains efficient ingression of the cleavage furrow.

<p>(<b>A</b>) Synchronized HeLa cells transfected with the indicated siRNAs were subjected to time-lapse live-cell imaging. Arrows indicate the ingressed cleavage furrow. (<b>B</b>) The cytokinesis progression of cells (<i>n</i>>40) that were selected at random and the time they spent in ingression before regression is plotted (top graph). All HeLa cells depleted of MKlp1 or MKlp2 formed a cleavage furrow and ingressed followed by furrow regression and cytokinesis failure, while none of the control cells showed furrow regression after ingression. The average duration of the furrow in ingression is based on three independent experiments (total <i>n</i>>100 per condition, +/− standard deviation) (bottom graph). To determine the statistical significance of the duration of the furrow in ingression Student’s <i>t</i>-test was performed. <i>P</i> values are indicated. (<b>C</b>) Immunoblot analysis of total cell lysates from panel <b>A</b>. C: control, M1: MKlp1, M2: MKlp2. Relative band intensities to control siRNA are shown in the bottom of each panel. (<b>D</b>) Immunofluorescence analysis using asynchronously grown HeLa cells was performed at 30 h after transfection with the indicated siRNAs. Cells in anaphase are shown. Images were acquired using 3D-SIM. Insets represent the boxed areas. White bars represent 5 µm.