PtdIns(3)P synthesis at tPCs is driven by the class III PtdIns 3-kinase, Vps34. (a) RAW cells expressing 2-FYVE-GFP (green) were treated with 1 µM DMSO (vehicle), 100 µM LY294002, 1 µM ZSTK474, or 1 µM Vps34-IN1. After these treatments, cells were allowed to engulf filamentous bacteria for 30 min, followed by fixation and staining for F-actin jackets. (b) RAW cells expressing 2-FYVE-GFP underwent phagocytosis for 20 min, followed by treatment with 1 µM Vps34-IN1 and then fixed after 25 min of treatment. Cells were stained as in panel b. (c) Cells from experiments in panels b and c were scored for the presence of PtdIns(3)P, detected via 2-FYVE accumulation at tPCs. Data shown are means ± SEMs from three independent experiments (n = 35 for each). P < 0.05. Bars, 5 µm. (d) RAW cells expressing 2-FYVE-GFP (green) were treated with 10 nM apilimod for 1 h before the phagocytosis. Representative phenotype from 90 cells analyzed in three independent experiments.