Figure 1.

EMT and Epithelial Plasticity. During EMT, epithelial cells lose their apico-basal polarity. Tight junctions which typically maintain apico-basal polarity dissolve allowing the mixing of apical and basolateral membrane proteins. Adherens and gap junctions are disassembled and cell surface proteins such as E-cadherin and epithelial-specific integrins (green) are replaced by N-cadherin and integrins specific to extracellular components (blue). The actin cytoskeleton is remodeled into stress fibers which accumulate at areas of cell protrusions. The epithelial intermediate filaments, cytokeratins, are replaced by vimentin. Meanwhile, the underlying basement membrane is degraded and the cell invades and moves into the surrounding stroma, devoid of cell-cell contacts.