Figure 6. MARK2i promotes equatorial... | Rockefeller University Press

Figure 6.

$MARK2i promotes equatorial movement of the mitotic spindle. (a) Experimental regime. HeLa cells were exposed to MG132 (10 µM) 1 h before imaging. Either DMSO (control) or 5 µM MARK2 inhibitor (MARK2i) as indicated were added during imaging. (b) Representative brightfield images displaying cell cortex (gray) and maximum projection live-cell images of a HeLa cell expressing H2B-GFP (green) and mCherry-Tubulin (magenta). Equatorial-centered and off-centered spindles are marked (E-C) and (E-OC), respectively. Cells were imaged over 1 h with images taken every 3 min. (c) Violin plots show fractions of longitudinal (∆lg), equatorial (∆eq), and axial (∆ax) spindle displacement. Corresponding colored dots represent measurements from all time points of the same cell. The white marker within the box refers to the median, the shaded area refers to the estimated kernel probability density and the box indicates the interquartile range of the data. (d) Cartoon shows a 3D spindle (gray) with the corresponding rotation angles α (spindle tumbling), β (spindle rolling), and γ (spindle rotation) along its principal spindle axes x,y,z, respectively. (e) Violin plots show 3D angle distribution for α spindle tumbling, β rolling, and γ rotation. Corresponding colored dots represent measurements from all time points of the same cell. The white marker within the box refers to the median, the shaded area refers to the estimated kernel probability density, and the box indicates the interquartile range of the data. Statistical significance was determined by Mann–Whitney U test (in c and e) after a pre-analysis of the underlying distribution with a Shapiro–Wilk test. N = 11 control and N = 12 MARK2i cells across three separate experiments. Scale bars: 5 µm.$

MARK2i promotes equatorial movement of the mitotic spindle. (a) Experimental regime. HeLa cells were exposed to MG132 (10 µM) 1 h before imaging. Either DMSO (control) or 5 µM MARK2 inhibitor (MARK2i) as indicated were added during imaging. (b) Representative brightfield images displaying cell cortex (gray) and maximum projection live-cell images of a HeLa cell expressing H2B-GFP (green) and mCherry-Tubulin (magenta). Equatorial-centered and off-centered spindles are marked (E-C) and (E-OC), respectively. Cells were imaged over 1 h with images taken every 3 min. (c) Violin plots show fractions of longitudinal (∆lg), equatorial (∆eq), and axial (∆ax) spindle displacement. Corresponding colored dots represent measurements from all time points of the same cell. The white marker within the box refers to the median, the shaded area refers to the estimated kernel probability density and the box indicates the interquartile range of the data. (d) Cartoon shows a 3D spindle (gray) with the corresponding rotation angles α (spindle tumbling), β (spindle rolling), and γ (spindle rotation) along its principal spindle axes x,y,z, respectively. (e) Violin plots show 3D angle distribution for α spindle tumbling, β rolling, and γ rotation. Corresponding colored dots represent measurements from all time points of the same cell. The white marker within the box refers to the median, the shaded area refers to the estimated kernel probability density, and the box indicates the interquartile range of the data. Statistical significance was determined by Mann–Whitney U test (in c and e) after a pre-analysis of the underlying distribution with a Shapiro–Wilk test. N = 11 control and N = 12 MARK2i cells across three separate experiments. Scale bars: 5 µm.