Ipl1 and Mcm21 mediate spindle disassembly by regulating She1 activity. (A) Protein extracts isolated from asynchronous populations of the indicated strains were separated by SDS-PAGE supplemented with 20 µM Phos-tag acrylamide. Detection of Pgk1 was used as a loading control. WB, Western blotting. (B) Frequency in which spindles disassembled after initiation of cytokinetic ring contraction in the indicated strains (n = 3 experiments each analyzing 20 disassembly events for each strain; mean ± SD). (A and B) WT, wild type. (C) Protein lysate from cells expressing She1-13Myc and Mcm21-GFP was passed over a column conjugated either to anti-Myc antibody (+Ab) or nothing (−Ab). Mcm21-GFP copurified with She1-13Myc only when anti-Myc antibody was conjugated to the column. IP, immunoprecipitation. (D) She1-3GFP localization in wild-type and mcm21Δ cells expressing the spindle marker mCherry-Tub1 during late anaphase (n = 80 for both strains). (E) Ipl1-3GFP localization in wild-type and mcm21Δ cells during late anaphase (n = 40 for both strains). Bars, 5 µm.