Actomyosin structures at the apical junction. (A) Comparison of actomyosin meshwork and cables with apical stress fiber and contractomere. Apical stress fibers can selectively link neighboring junctions as well as junctions from opposite sides of a cell. Contractomere is a unique actomyosin structure that contains non-filamentous myosin II. (B) Comparison between actomyosin meshwork and apical stress fiber is shown at the top panels. Apical stress fibers inserted at cell–cell adhesion can propagate force across many cells in an epithelial monolayer, the bottom panel. (C) Shortening and lengthening the junction by “walking” the contractomere. Motility of contractomere contributes to junction constriction during cell extrusion and pure-string wound closure. Prevailing model of junction remodeling requires disassembly of junction actomyosin cortex and endocytosis of existing junction. (D) Contractomere generates intrinsic force whereas apical stress fiber or actomyosin meshwork generates extrinsic force with respect to the junction. Contractomere is powered by myosin II and actin polymerization locally at the junction while apical stress fiber is powered by myosin II at a distance away from the junction. (E) Key to cartoon.