Erbb2 signaling is essential for Cdh2-EGFP localization on the basal side of cardiomyocytes. (A–A′′ and B–B′′) Spinning disk confocal images of TgBAC(cdh2:cdh2-EGFP) hearts. Localization of Cdh2-EGFP in 96 hpf control (wild-type), Erbb2 inhibitor-treated, and erbb2 mutant hearts is shown in the single 2D planes (A–A′′) and 3D reconstructed images (B–B′′). Illustrations of Cdh2-EGFP distribution are shown on the right. (C–C′′) Red, blue, and yellow rectangles shown in the zoomed images are from B–B′′. (D and E) tFT intensity ratio of Cdh2 molecules measured in the regions indicated by the white arrows (E–E′). (F) Schematic diagram depicting Cdh2 localization only at the cell–cell junctions in Erbb2 inhibitor-treated or erbb2 mutant larvae at 96 hpf. (G) Cross-sectional area of Cdh2-EGFP punctae at 96 hpf in DMSO control and Erbb2 inhibitor-treated larvae. (H) Illustration comparing Cdh2 organization in wild-type, stopped, and Erbb2 inhibitor-treated/mutant hearts. (Scale bar: 10 μm in A–A′′, B–B′′, and C–C′′; 5 μm in E and E′.)