Fig. 1: Cells at different phases of the EMT spectrum display varying combinations and degrees of cellular features associated with epithelial or mesenchymal states.

Epithelial cells form connections with one another through different types of junctions, including adherens junctions, desmosomes, gap junctions, and tight junctions. The proper organization these cell-cell adhesion in epithelial cells is guided by apical-basal polarity. The epithelial cells are connected to the underlying basement membrane via hemidesmosomes, which contains integrin that facilitates binding to the basement membrane and is also linked to cytokeratins within the cell. Mesenchymal cells lack functional epithelial junctions and exhibit back-front polarity in their actin stress fibers. Vimentin-based intermediate filaments are present in mesenchymal cells, and they use integrin-containing focal adhesions to attach to the extracellular matrix. Some of the transcription factors and regulators known to regulate the different phases of the epithelial-to-mesenchymal transition are shown below the spectrum (epithelial regulators – purple, and mesenchymal regulators, orange).