a, Single-cell traces of CDK2 and ERK activities. Mitogens were withdrawn 0–2 h after mitosis. b, Box plot of mean ERK activity during the G2 or G0/G1 phases based on CDK2 classification. The higher ERK activity in CDK2delay cells during G0/G1 compared to CDK2low cells suggests that ERK activity in G0/G1 regulates the delayed entry into the cell cycle. Yellow lines indicate the median, boxes denote the 25th and 75th percentiles, lines denote the total range for each population (n = 2,896 cells). c, Examples of ERK single-cell traces classified by CDK2 paths in daughter cells. d, Bar graph of differences in integrated ERK activity during the G0/G1 phases based on CDK2 classification. Corresponding fold changes in cyclin D1 were calculated based on Extended Data Fig. 2e. Data are mean ± s.d. (n = 3 biological replicates). e, Analysis of the fraction of daughter pairs from the same and different mothers that have the same CDK2 path. Data are mean ± s.d. (n = 24 wells (each well; n > 100 cells)). f, g, Odds ratio analysis showing how well the percentile of ERK activity in G2 for varying mitogen availability (f) and temporal proximity to mitosis (g) predicts cell-cycle entry in daughter cells. Strong prediction values are shown in blue, and random chance is marked as a purple dashed line. Data are mean ± s.d. (n = 3 (f) and n = 2 (g) biological replicates).