APC/C-Cdh1-mediated securin degradation is required for sister-chromatid separation during mitotic slippage. (A) Cells of strains SCU2755 (PDS1-HA3), SCU408 (bub2Δ PDS1-HA3) and SCU2834 (bub2Δ cdh1Δ PDS1-HA3) were released from α-factor into the nocodazole-containing medium (time 0), as described in Figure 1. HA-tagged securin (Pds1-HA3) was detected by western blotting analysis using an anti-HA antibody. CDK and glucose-6-phosphate dehydrogenase (G6PDH) were used as the loading controls. (B, C) Cells of strain SCU396 (bub2Δ CEN-GFP) with plasmids pSCU1212 (pGAL1-pds1-db) or pSCU1214 (pGAL1-pds1-dkb) were released from α-factor into nocodazole-containing SGalR medium (time 0), as described in Figure 1. Representative cells at the 6 h time point are shown. The data for bub2Δ cells are taken from Figure 1.