Apical stress fibers insert at the apical junctions of epithelial cells. (A) Immunofluorescence showing alternating arrangement of synaptopodin and myosin IIB forming sarcomere-like repeats. Scale bar is 2 μm. (B) Immunofluorescence showing apical stress fibers inserted at cell–cell adhesions to connect multiple cells. Insets show colocalization of synaptopodin and α-actinin-4 on apical stress fibers. Scale bar is 5 μm. Inset scale bar is 1 μm. (C) Thin-section transmission electron microscopy showing actin bundle connected to the apical junction on one end and a sarcomere-like structure on the opposite end. Scale bar is 200 nm.