TISSUE ARCHITECTURE - THE ULTIMATE REGULATOR OF EPITHELIAL FUNCTION

The architecture of a tissue is defined by the nature and the integrit y of its cellular and extracellular compartments, and is based on prop er adhesive cell-cell and cell-extracellular matrix interactions. Cadh erins and integrins are major adhesion-mediators that assemble epithel ial cells together laterally and attach them basally to a subepithelia l basement membrane, respectively. Because cell adhesion complexes are linked to the cytoskeleton and to the cellular sir:nalling pathways, they represent checkpoints for regulation of cell shape and gene expre ssion and thus are instructive for cell behaviour and function. This o rganization allows a reciprocal flow of mechanical and biochemical inf ormation between the cell and its microenvironment, and necessitates t hat cells actively maintain a state of homeostasis within a given tiss ue context. The loss of the ability of tumour cells to establish corre ct adhesive interactions with their microenvironment results in disrup tion of tissue architecture with often fatal consequences for the host organism. This review discusses the role of cell adhesion in the main tenance of tissue structure and analyses how tissue structure regulate s epithelial function.