Structure and Functional Role of Endothelial Cell-to-Cell Junctions
Endothelial cell junctions are complex structures formed by transmembrane adhesive molecules linked to a network of cytoplasmic/cytoskeletal proteins. These structures have some features and components in common with epithelial cells but also some which are specific for the endothelium. During angiogenesis, endothelial cells need first to dissociate from neighbouring cells and invade the underlying tissues. Indirect evidence suggests that vascular growth factor(s), besides inducing endothelial cell proliferation, could also change endothelial junction organization and strength. After the first sprouting the new vascular structures get organized in a more complex network. At this stage, molecules at junctions are required for endothelial cell-to-cell anchorage and for vascular remodelling. These structures are important not only for maintaining adhesion between endothelial cells and, as a consequence, for the control of vascular permeability, but also for intracellular signal transduction. The exact pathways of signalling through cell-to-cell contacts are still obscure but seem to require the release of intracellular molecules from the junctional complex and their translocation to the cytoplasm and/or the nucleus.
KeywordsTight Junction Intercellular Junction Vascular Endothelial Cell Growth Factor Cytoplasmic Component Adenomatous Polyposis Coli Protein
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