Synaptopodin apical stress fibers are contractile structures distinct from basal stress fibers. (A) Frames taken from a time-lapse of synaptopodin and ZO-1 showing apical and basal stress fibers on different focal planes. Apical and basal stress fibers are inserted at apical and basal ZO-1 junctions, respectively. Scale bars are 2 μm. (B) Frames taken from a time-lapse of synaptopodin and ZO-1. Arrowheads point to sites of stress fiber attachment at the apical junction. Contraction events are circled. Dotted lines represent lengths of linear junction. Scale bar is 5 μm. (C) Frames taken from a time-lapse of synaptopodin and ZO-1. Arrowheads point to sites of stress fiber attachment at the apical junction. Contraction events are circled. Arrows point to direction of movement of the attached junction. Scale bar is 1 μm. (D) Frames taken from time-lapse of synaptopodin and ZO-1. Outline of a cell at time zero is drawn in all panels. Arrowheads point to stress fiber attachment sites at the apical junction. Contraction of apical stress fiber is circled. Scale bar is 10 μm.