Structural and functional associations of apical junctions with cytoskeleton.

Actin dynamics play multiple roles in promoting cell movement, changing cell shapes, and establishing intercellular adhesion. Cell contact events are involved in tissue morphogenesis, immune responses, and cancer cell invasion. In epithelial cells, cell-cell contacts mature to form apical junctions with which the actin cytoskeleton physically associates. Living cell imaging shows, however, that the apical junctional complex is less dynamically regulated than the actin cytoskeleton, indicating that their interaction does not remain stable. Given that several cell adhesion modules are clustered at apical junctions, the sum of weak or transient interactions may create linkages that can be strong yet easily remodeled. Here we describe how subcellular protein interactions are coordinated to induce changes in actin organization and dynamics, in response to the status of apical junctions.