Aurora B controls the size and stability of the central spindle through regulation of Kif2A. (A) Immunostaining of MTs (green) and Kif2A (red) in control or Kif2A-depleted cells treated with or without 5 µM ZM447439 for 15 min. (B) Line profiles of the anti-Kif2A immunostaining intensity along the central spindle in control and ZM447439-treated cells. The mean ± SE of ≥12 cells from three independent experiments is shown. (C) Normalized fluorescence intensity of Kif2A immunostaining on the central spindle. Cells were either treated with 2.5 µM ZM447439 (ZM) for 3 or 10 min during anaphase or cultured without the drug for 30 min (DMSO) before fixation. The mean ± SE of ≥11 samples from two independent experiments is shown. *, P < 10−4, t test. (D) Length of the central spindle after treating cells with 5 µM ZM447439 for 15 min. The mean ± SE of three independent experiments is shown (≥45 cells were analyzed for each treatment). *, P < 0.001, t test. (E) EGFP–α-tubulin–expressing cells depleted of INCENP or codepleted of INCENP and Kif2A. In the absence of INCENP alone, the central spindle (red arrows) oscillated, and the cell later regressed. (F–H) Frequency of central spindle destabilization, furrow regression, or uneven chromosome distribution in control, Kif2A-depleted, INCENP-depleted, or Kif2A/INCENP-codepleted cells. For each sample, ≥47 cells from four independent experiments were analyzed. a.u., arbitrary unit. Bars, 5 µm.
