Figure 3.

The actin cytoskeleton becomes depolarized in ras2Δ cells at 35°C. (A) RAS2⁺ (ABY1205) and ras2Δ (ABY1209) cells growing in YPD were shifted to 35°C for 30 min, fixed, and stained for actin. ras2Δ mutants became depolarized after a 30-min shift, whereas wild-type cells remained polarized. The arrow indicates a cell that was scored as polarized, although qualitatively the cell is not completely polarized. (B) RAS2⁺ (▪, ABY1205) and ras2Δ (●, ABY 1209) cells were shifted to 35°C, fixed at 0, 3, 7, 15, and 30 min, and stained for actin. One hundred small and medium budded cells were scored for actin polarization. A cell was scored polarized if >50% of total actin patch fluorescence was concentrated in the bud.