GSK-3 inhibitors increase inter-kinetochore distance. Drug-treated DLD-1 cells were fixed and stained to detect centromeres (ACA, red), kinetochores (Bub1 or BubR1, green), microtubules (green or blue) and the chromosomes (red) as indicated. (A, B) Projections of deconvolved image stacks showing reduced levels of Bub1 and BubR1 is at metaphase-kinetochores is reduced in GSK-3 inhibitor treated cells. Scale bars: 5 μm. (C) Projections of deconvolved image stacks showing the asymmetric labelling of Bub1 on the kinetochore of mono-orientated chromosomes. (D) Bar graph quantifying inter-kinetochore distance at metaphase chromosomes. Values represent the mean and s.e.m. derived from at least 20 kinetochores in at least 3 cells. (E, F) Bar graphs quantifying the levels of Bub1 and BubR1 at aligned chromosomes. Values represent the mean and s.e.m. derived from at least 64 kinetochores in at least 3 cells. The cells shown in (A) were treated with 30 μM SB-415286 and in (B) with 10 μM CHIR99021.