Apical junction contains a latrunculin-resistant stable pool of actin that serves as sites of Arp2/3-dependent actin incorporation. (a) Projection of the first 10 deconvolved optical z slices spanning 2 µm from the apical region of latrunculin-treated cells. (b) Projection of the next 30 deconvolved optical z slices spanning the next 6 µm of the basal regions of latrunculin-treated cells. (c and d) Single deconvolved optical z slices showing incorporation of fluorescently labeled actin (red) at latrunculin-stable actin puncta (phalloidin; green) in permeabilized cells (yellow arrowheads). (e) Arp3 (red) is colocalized (yellow arrowheads) with latrunculin-stable actin puncta (phalloidin; green). Projection of five deconvolved optical z slices spanning 1 µm from the apical region of cells. (a–e) Bars, 2 µm. (f) Projection of the first five deconvolved optical z slices spanning 1 µm from the apical region of cells after 30 min of latrunculin B (LatB) washout. (g) Projection of the first five deconvolved optical z slices spanning 1 µm from the apical region of cells 30 min after latrunculin washout in the presence of Arp2/3 inhibitors CK-548 and CK-636. (h) Projection of the first five deconvolved optical z slices spanning 1 µm from the apical region of cells 30 min after latrunculin washout in the presence of formin inhibitor SMIFH2. (a–c and f–h) Yellow arrowheads point to areas where β-catenin and actin (phalloidin) are colocalized. White arrowheads point to areas where actin is missing from β-catenin puncta. (f–h) Bars, 10 µm.