The PI-3 kinase pathway plays a cell type–specific role in CME. (A) Representative kymographs of hESCs, NPCs, and fibroblasts treated with DMSO or 1 µM LY for 20 min. CLTA-TagRFP-T (magenta) and DNM2-EGFP (green). Bar, 5 µm. (B) Density of stalled events in LY-treated cells relative to respective DMSO-treated cells (mean ± SEM). ***, P < 0.0001, one-way ANOVA and Dunnett’s test versus control (five independent experiments, three to four cells analyzed per experiment, 60–800 structures analyzed). (C) Productivity of endocytic events in LY-treated cells relative to respective control cells (mean ± SEM). ***, P < 0.001, one-way ANOVA and Dunnett’s test versus control (five independent experiments, three to four cells analyzed per experiment, 60–800 structures analyzed). (D) Lifetimes for clathrin and dynamin in hESCs, NPCs, and fibroblasts treated with DMSO or 1 µM LY. Box plots show median lifetimes between the 25th to 75th percentiles. The full range covering the minimum to maximum data points is shown (mean ± SEM). ***, P < 0.001, one-way ANOVA and Dunnett’s test versus control (five independent experiments, three to four cells analyzed per experiment, 60–800 structures analyzed).