Mechanical stretch impairs alveolar epithelial integrity. The alveolar epithelial tight junction is consists of several constituents of connected proteins. Occludin is a transmembrane protein known to be associated with F-actin, either directly or indirectly modulating the tight junction structure. Mechanical stretch of alveolar epithelial cells can result in loss of tight junction structure and cell–cell attachment associated with decrease in the expression or increase in degradation of occludin and actin perturbations. The actin cytoskeleton remodeling plays an important role in fibrosis formation in the lung. ATI = alveolar type I; ATII = alveolar type II.