FIGURE 5:

Importance of the Hof1–Cyk3 interaction for cleavage-furrow ingression and the formation of normal septa. (A) Slow constriction of the CAR in the absence of the Hof1–Cyk3 interaction. Constriction of the Myo1–GFP ring was observed by time-lapse microscopy in wild-type (MWY1327), cyk3^PAPA (MWY1315), and hof1^WA (MWY1317) strains. All strains were grown to exponential phase and examined in SC medium at 24°C. Times are indicated in minutes; the onset of constriction is set at 0. Mean ± SD constriction times for 10 cells of each genotype were 6.6 ± 0.8 min (wild type), 13.4 ± 2.7 min (cyk3^PAPA), and 11.4 ± 2.4 min (hof1^WA). Scale bar, 2 µm. (B, C) Abnormal septal structures in the absence of the Hof1–Cyk3 interaction. Strains (B) MWY732 (cyk3^PAPA) and (C) MWY864 (hof1∆ [pHOF1^WA]) were grown to exponential phase at 24°C in SC (MWY732) or SC–Leu (MWY864) medium and examined by electron microscopy. Representative images are shown (see text). Scale bars, 0.2 µm.