Recruiting Aurora B to the cell cortex and the growing furrow by MKlp2 is required for stable polarization and furrow formation during monopolar cytokinesis.

<p>(<b>A–C</b>) Immunofluorescence analysis of Dox-inducible HeLa cells undergoing monopolar cytokinesis. Flag-MKlp2 expression was induced with Dox for 20 h after the transfection of MKlp2 siRNA. After Dox-treatment, cells were treated with monastrol for 6 h and then treated with Purv A or DMSO for 20 min before fixation in ice-cold methanol. (<b>A, B</b>) Flag-MKlp2(1-890) localized to the cell cortex and at the growing furrow together with Aurora B (A, panels b-d) and INCENP (<b>B</b>, panels a, b), but Flag-MKlp2(1-842) only localized to the ends of monopolar spindles together with Aurora B (<b>A</b>, panels f-h) and INCENP (<b>B</b>, panels c, d). (<b>C</b>) In contrast to Aurora B and INCENP in panels <b>A</b> and <b>B</b>, centralspindlin and PRC1 were efficiently localized to the ends of monopolar spindles in cells expressing Flag-MKlp2(1-890) and MKlp2(1-842). This finding indicates that Flag-MKlp2(1-842) is selectively defective in targeting Aurora B and INCENP (thus, most likely the CPC) from the monopolar spindles to the cell cortex. (<b>D</b>) The average percentages based on three independent experiments of non-polarized, polarized (determined by the direction of Flag-MKlp2 and the monopolar spindles towards the cell cortex) or furrowed cells (determined by the presence of Flag-MKlp2 and myosin-II in the furrow) expressing Flag-MKlp2 (<i>n</i>>100 per condition, +/− standard deviation) are shown.