Fig. 5

Changes in volume are sufficient to induce changes in tubulin polymer levels. a Representative time-lapse confocal images (x-y maximum projection, lower panel: pseudo-color, spectra LUT) of HeLa cells stably expressing H2B-mRFP (not imaged) and mEGFP-α-tubulin showing changes in spindle mEGFP-α-tubulin intensity and spindle volume upon hypo- or hyper-osmotic shock relative to a control. Scale bar represents 10 μm. b Quantification of changes in spindle mEGFP-α-tubulin intensity induced by osmotic shock. Mean intensity of spindle mEGFP-α-tubulin intensity was measured by rendering mitotic spindles in three dimensions (3D) using Imaris software before and after control (blue, 12 cells), hypo (red, 14 cells) or hyper (green, 10 cells) osmotic shock treatment (two independent experiments). Lower panel: comparison between –0.5 min and 2 min relative to osmotic shock treatment. Repeated measures two-way ANOVA, Dunnett's multiple comparisons test, ****P = 0.0001. c Quantification of changes in spindle volume induced by osmotic shock. Spindle volume was measured by rendering mEGFP-α-tubulin signal in 3D in Imaris before and after control (blue, 12 cells), hypo (red, 14) or hyper (green, 10 cells) osmotic shock treatment (two independent experiments). Lower panel: comparison between –0.5 min and 2 min relative to osmotic shock treatment. Repeated measures two-way ANOVA, Dunnett's multiple comparisons test, ****P = 0.0001