WAVE complex at junctions. (A and B) Coimmunostaining for Abi1 and E-cadherin in wild-type (A) and αEcat KO (B) Caco2 cells. IF signals in the boxed regions, which are enlarged at the right, were scanned along the line (not depicted) drawn between the white arrowheads. Asterisk in the image indicates a position roughly corresponding to the peak labeled with the same symbol on the scan, throughout the figures. J, the position of cell junction. In B, IF signals were also scanned along the line marked a and b. Larger arrows point to Abi-positive protrusions; small arrow, a protrusion having E-cadherin, which is outlined with a broken line at the rightmost image. Green arrowheads point to a closed junction. (C) IF signals for Abi1 that overlap or do not overlap those for E-cadherin were measured using interior cells, and the ratio of the nonoverlapping to the total signals was plotted. For measurement, a few points in each of the bicellular junctions were randomly selected, using four wild-type and three αE-cat KO cells. ****, P < 0.0001 (t test, one-sided). (D) Coimmunostaining for Abi1 and actin in wild-type or αEcat KO Caco2 cells. IF signals were scanned as explained in A. Marginal and submarginal cells are shown. J, the position of cell junction. (E) Effect of siRNA-mediated Nap1 depletion on actin assembly. The boxed areas are enlarged, being placed under each panel. Arrows indicate protrusions. Marginal and submarginal cells are shown. Magnification is shown in the partly enlarged images. Scale bars, 10 µm.