Figure 7.

Lack of septin SUMOylation interferes with late steps of cytokinesis. (a) Representative images from time-lapse microscopy analysis of HeLa cells expressing WT or non-SUMOylatable SEPT7. Images correspond to different cell division events including cell rounding, cleavage furrow ingression, intercellular bridge formation, and either bridge abscission (top) or bridge regression and formation of a binucleated cell (bottom). Bars, 10 µm. (b) Time-lapse microscopy analysis of HeLa cells transfected with control plasmid (pCDNA.3; CTRL) or expression vectors for SEPT7 WT, KRc, or KRc^SUMO1 variants. 24 h after transfection, time-lapse sequences of cells were recorded every 20 min for 48 h. At least 50 transfected cells were analyzed for each condition in each experiment. Means ± standard errors from three independent experiments are indicated. *, P < 0.05 compared with control condition (two-tailed two-sample equal-variance Student’s t test). ^aPercentage of cells for which cell division results in the formation of binucleated cells. ^bTime between cell rounding and furrow ingression. ^cTime between cell rounding and intercellular bridge abscission. ^dTime between two cell-rounding events. n.a., not applicable.