Actin localization. Shown are representative YF cells at different stages of the cell cycle of diploid strains expressing wild-type CDC42 (wt) or CDC42 mutant alleles (N26I, A30T, I46M, D65N, S71P, N92D, E100G, or L160P) or carrying a bni1 mutation (RH2488). Strains were grown to the logarithmic growth phase in nutrient-rich medium, fixed, and stained with the actin fluorescent stain rhodamine-phalloidin before observation using either fluorescence microscopy or DIC microscopy. Bar, 5 μm.