Figure 1.

The descriptive diagram model of composition and interactions between proteins that are part of the cell union complex. (A) The Occlusion Junctions seal the spaces between epithelial cells, and it is of paramount importance in sealing the epithelial tissues to water molecules and ions, making the passive diffusion of ions impossible; here Occludins and Claudins act. (B) The Adherens Junctions connect the bundles of Actin Filaments of one cell with the bundles of another cell where the primary function is to promote adhesion between neighboring cells being crucial in tissue architecture; here Cadherins, α-Catenins, β-Catenins, p120-Catenin, and Vinculins acts. The regulation of the cell–cell adhesion complex is mediated by E-Cadherin and can favor the transformation of epithelial cells into mesenchymal cells after triggering EMT inducers in the various pathways involved; among those involved, the SNAIL protein helps to promote this process by blocking the E-Cadherin. (C) Desmosomes connect the Intermediate Filaments of one cell with those of the other cell, with the main aim of promoting intercellular adhesion, not interfering with other junctions; here Desmogleins, Desmocolins, Plakoglobin, Desmoplakin, and the Intermediate Filaments are involved. (D) The Gap Junctions allow the passage of water-soluble molecules from one cell to another; it is formed by six subunits of Connexins forming a hexagonal complex. (E) Hemidesmosomes anchor the cell’s Intermediate Filaments to the Extracellular Matrix—Cell/Matrix adhesion anchors the Actin Filaments of the cell to the Extracellular Matrix, connecting the Intermediate Filaments of the Cytoskeleton with the Extracellular Matrix; here α-Integrins and β-Integrins are involved.