Actin Cytoskeleton Remodeling Accompanied by Redistribution of Adhesion Proteins Drives Migration of Cells in Different EMT States

Abstract

Epithelial–mesenchymal transition (EMT) is a process during which epithelial cells lose epithelial characteristics and gain mesenchymal features. Here, we used several cell models to study migratory activity and redistribution of cell–cell adhesion proteins in cells in different EMT states: EGF-induced EMT of epithelial IAR-20 cells; IAR-6-1 cells with a hybrid epithelial–mesenchymal phenotype; and their more mesenchymal derivatives, IAR-6-1-DNE cells lacking adherens junctions. In migrating cells, the cell–cell adhesion protein α-catenin accumulated at the leading edges along with ArpC2/p34 and α-actinin. Suppression of α-catenin shifted cell morphology from fibroblast-like to discoid and attenuated cell migration. Expression of exogenous α-catenin in MDA-MB-468 cells devoid of α-catenin drastically increased their migratory capabilities. The Y654 phosphorylated form of β-catenin was detected at integrin adhesion complexes (IACs). Co-immunoprecipitation studies indicated that α-catenin and pY654-β-catenin were associated with IAC proteins: vinculin, zyxin, and α-actinin. Taken together, these data suggest that in cells undergoing EMT, catenins not participating in assembly of adherens junctions may affect cell migration.