Shortening of the inner KT/centromere after MT severing. (A) Maximum intensity projections of a merotelic KT in PtK1 cells expressing GFP-CenpA (green) and injected with α-tubulin–X-rhodamine (magenta). Time 0 indicates the frame before ablation. The white lightning sign indicates the ablation site. Images were acquired with a time resolution Δt = 2.4 s. Close-up views show lagging KTs (1.85×). (B) Time projection of the area containing the merotelic KT from the cell in A. The boxed region indicates the time interval shown in A. (C) Relaxation kinetics of the merotelic KT from A and B. The red dashed line indicates the severing time. (D) Maximum intensity projections of a merotelic KT in fission yeast cell expressing Cnp1-GFP, shown in green, and α-tubulin–mCherry, shown in magenta. The white lightning sign indicates the ablation site. The time 0 is the frame before ablation. The spindle breakage occurred immediately after ablation. Images were acquired with a time resolution Δt = 3.2 s. Close-up views show lagging KTs (1.5× magnification). (E) Time projection of an area containing the merotelic KT from the cell in D. The boxed region indicates the time interval shown in D. (F) Relaxation kinetics of the merotelic KT from D and E. The red dashed line indicates the severing time.