Cdc42 is inactivated at late anaphase to preserve normal cell size. (A) Cartoon of actin filament and actin patch localization throughout the budding yeast cell cycle. (B) Representative time-lapse images showing the localization of actin patches by monitoring Abp1-3xmCherry during mitosis in a wild-type cell. Numbers indicate time in minutes from the initial polarization of actin patches. Cells were synchronized in G1 with α factor and released. Scale bar, 5 µm. (C) Timing of anaphase onset, actin patch redistribution, and spindle breakdown (n = 70 cells from three experiments). (D) Representative time-lapse images showing localization of a GTP-Cdc42 biosensor (Gic2-PBD-RFP) during mitosis in a wild-type cell. Numbers indicate time in minutes from the initial polarization of GTP-Cdc42 in G1. Cells were synchronized in G1 with α factor and then released. Scale bar, 5 µm. (E) Timing of anaphase onset, Cdc42 redistribution, and spindle breakdown (n = 100 cells from three experiments). (F) Gic2-PBD-RFP fluorescence intensity (n = 30 cells from three experiments for each time point indicated). Average intensity from each cell compartment was normalized over the total intensity in the cell, and the average ratio from 30 cells is plotted for each time point. Error bars represent SEM. (G) Cell volume of buds and mothers (n = 30 cells from three experiments for each time point indicated; average ± SEM). (H) Growth rate before and after Cdc42 redistribution (n = 100 cells from three experiments; average ± SEM). Asterisks indicate statistically significant differences (****, P < 0.0001, paired t test). ns, not statistically significant.