Multiscale dynamics of tight junction remodeling

Epithelial cells form tissues that generate biological barriers in the body. Tight junctions (TJs) are responsible for maintaining a selectively permeable seal between epithelial cells, but little is known about how TJs dynamically remodel in response to physiological forces that challenge epithelial barrier function, such as cell shape changes (e.g. during cell division) or tissue stretching (e.g. during developmental morphogenesis). In this Review, we first introduce a framework to think about TJ remodeling across multiple scales: from molecular dynamics, to strand dynamics, to cell- and tissue-scale dynamics. We then relate knowledge gained from global perturbations of TJs to emerging information about local TJ remodeling events, where transient localized Rho activation and actomyosin-mediated contraction promote TJ remodeling to repair local leaks in barrier function. We conclude by identifying emerging areas in the field and propose ideas for future studies that address unanswered questions about the mechanisms that drive TJ remodeling.