PtdIns(3)P lipids are found in multiple organelle membranes. (A–D) The GFP-2×FYVE probe was used as a marker for the localization of cellular PtdIns(3)P lipids. Representative images show GFP-2×FYVE localization to PtdIns(3)P-containing membranes of synaptic vesicles labeled by synaptophysin-dsRed (A), lysosomes labeled by LAMP1-GFP (B), early endosomes labeled by Rab5-RFP (C), and mitochondria labeled by mito-dsRed (D). Insets show high magnification views of the boxed regions. Arrowheads indicate areas of colocalization. Data shown are for one experiment out of three repeats.