Bim1 phosphorylation affects spindle dynamics and midzone disassembly in vivo. (A) Averaged kinetics of anaphase spindle elongation in WT, BIM1^6A, BIM1^6D, and bim1Δ cells followed by live cell microscopy of strains expressing GFP-TUB1. (middle and bottom) Quantification of maximum anaphase spindle length and metaphase spindle length in the different bim1 mutants. Error bars denote standard error of the mean. **, P = 0.0011. (B) Live cell microscopy of BIM1–3× GFP and BIM1^6A–3× GFP during spindle disassembly in strains expressing mCherry-TUB1. The middle panels show kymographs (space–time plots) of midzone disassembly in the WT and in the BIM1^6A background. The bottom panels show individual frames from the corresponding videos for a WT spindle (Video 6) and for the 6A mutant (Video 7). Arrows show separation of the Bim1 signal on the spindle. Bars, 3 µm.