PARI and Aurora B function in the same pathway to inhibit abscission. (A) Cells treated with ICRF-193 progressing from anaphase to midbody formation (GFP-alpha-tubulin) and its disassembly. The Aurora B inhibitor hesperadin was added 120 min after the start of acquisition when most cells on average had formed the midbody. Asterisk specifies midbody disassembly. Scale bar: 5 um. (B) Quantification of the midbody lifetime (time from midbody formation to severing). (C–E) Immunofluorescence images showing Aurora B phosphorylated on T232 (pT232-AurB, magenta), GFP-α-tubulin (green), and H2B-mCherry (gray) (in C); DAPI (cyan), α-tubulin (green), and Topo IIα (red) (in D); and DAPI, α-tubulin (green), and MRE11 (red) in E. Quantifications (right) show the levels of the indicated proteins at the midbody. In plots in B–E, each circle represents one cell, pooled from two or three independent experiments; triangles indicate the mean value of each experiment; bars indicate the median ± IQR. The Mann–Whitney test was used for statistical analysis; P-values are indicated. P > 0.05 = ns. Scale bars: 5 µm in A and C; 10 µm in D and E.