High-Cdk1 quiescence entry is determined by the stress status of the cell during starvation. (A) Schematic of nocodazole cell cycle synchronization before starvation onset. (B–E) Average time series for low-Cdk1 (blue) and high-Cdk1 (red) Q-cells with the same cell cycle progression around starvation onset after nocodazole arrest-release. Average time series for Cdc10 (B) and the nuclear intensity of Xbp1 (C), Gln3 (D), and Sfp1 (E) in nocodazole arrest-released cells with same cell cycle progression at starvation onset (n = 3; 96 cells). (F) Schematic of stress induction before starvation onset. (G) Nuclear intensity of stress factors as population average upon glucose depletion before starvation (504 cells). (H) Schematic of glucose depletion–induced stress response network. (I) Nuclear intensity of stress factors as population average upon nitrogen depletion before starvation (222 cells). (J) Schematic of nitrogen depletion–induced stress response network. (K) Percentage of high-Cdk1 Q-cells upon 20-h starvation in 6C1 cells with the following treatments before starvation: unsynchronized and unstressed control (Ctrl); nocodazole-synchronized (Noc.); 2-h glucose depletion; 2-h nitrogen depletion (n = 7 per treatment). (L and M) Quantification of the final nuclear intensity of stress markers after 20-h starvation in low-Cdk1 (blue) and high-Cdk1 (red) Q-cells pretreated with glucose (L) or nitrogen (M) depletion for 2 h before starvation (n = 7; >233 cells). Solid lines with shaded area = average ± 95% confidence intervals. Red arrowheads = onset of starvation. Red star = P < 0.05, K-S test. Bar plots = mean ± SD. Box plots display data from biological replicates: central mark, median; box bottom and top limit, 25th and 75th percentiles; whiskers, most extreme nonoutlier values.