Figure 2.

Junction biogenesis in vitro and associated cytoskeletal arrangements. Following cell contact in vitro, initial cadherin engagement triggers reorganization of the cytoskeleton, coordinated with downstream assembly of tight junctions and desmosomes. In polarized simple epithelial cells, the maturation of junctional contacts is accompanied by the formation of a circumferential zone of parallel microfilament bundles near the apical region of the cell, below the tight junction barrier. Desmosomes are subjacent to this complex and also appear as disclike structures that extend along the entire lateral border, where they anchor IF to the plasma membrane. MTs also anchor at AJs and DSMs.