Kif2A is required for icMT sizing and organization. (A) Cells expressing RacGAP1-GFP were treated with DMSO (control) or 4 µM taxol for 5–10 min before image acquisition. (B) Frequency of stem body misalignment in DMSO- or taxol-treated cells. The mean ± SE of three independent experiments is shown (≥34 cells were analyzed for each treatment). *, P < 0.01, t test. (C) RacGAP1-GFP dynamics in control (luciferase RNAi) or Kif2A-depleted cells. (middle) Kif2A depletion resulted in stem body misalignment (red arrow) and broadening of the stem body cluster at early telophase (18 min). (bottom) Global misalignment of stem bodies resulted in formation of the perpendicularly tilted division plane. Some of the misaligned stem bodies were separated from the others during telophase (yellow arrowheads). Broken lines indicate cell boundaries. Note that the cell itself did not rotate during division plane rotation. (D) Frequency of stem body misalignment in control or kinesin-depleted cells. The mean ± SE of four (luciferase RNAi) or three (others) independent experiments is shown (≥26 cells were analyzed for each treatment). *, P < 0.01, t test; **, P < 10−4. (E) Immunostaining of MTs and RacGAP1 in control or Kif2A-depleted cells. A buckled MT bundle associated with a misaligned stem body (pink arrow) is highlighted with white arrowheads. (F) Ratio of MT bundle length to chromosome-to-chromosome distance in control or Kif2A-depleted cells. For Kif2A RNAi samples, the MT bundles associated with aligned or misaligned stem bodies were separately analyzed. The mean ratio (±SE) of ≥15 pairs of MT bundles in at least six cells from two independent experiments is shown. *, P < 10−7, t test. Bars, 5 µm.
