Title:
Remodeling of Adherens Junction for Epithelial Morphogenesis

Masatoshi Takeichi
Director,
RIKEN Center for Developmental Biology

Abstract:
Epithelial tissues are the major components of many organs, in which cells are tightly connected together through cell-cell junctions, displaying an apparently static structure. In fact, epithelial cells exhibit dynamic behavior, such as rearrangement and shape changes, particularly during embryonic development and also tissue regeneration or repair in adult organs. And this property of epithelial cells is crucial for remodeling tissue architecture, a process required for animal body formation. Evidence is accumulating that epithelial cell behavior is controlled through the modulation of cell junctions to a large extent. A major structure responsible for cell junction formation is the adherens junction (AJ). The AJ is made up of cadherin adhesion receptors and associated cytoplasmic proteins, including actomyosin filaments and microtubules. The linkage between adhesion receptors and cytoskeletal elements makes the AJs plastic, allowing the junctions to contract or extend, or to stabilize or destabilize. Responding to these changes in AJs, epithelial tissues undergo various forms of reshaping such as apical constriction, folding and migration, which in turn results in global changes in tissue morphology. In this seminar, I will discuss the molecular mechanisms by which the AJs are modulated, and how AJ modulation leads to epithelial cell rearrangement, focusing on neural plate bending processes.

References:
Taguchi, K., T. Ishiuchi, and M. Takeichi. (2011) Mechanosensitive EPLIN-dependent remodeling of adherens junctions regulates epithelial reshaping. The Journal of cell biology . 194:643-656.

Nishimura, T., Honda, H. & Takeichi, M. (2012) Planar cell polarity links axes of spatial dynamics in neural-tube closure. Cell 149 , 1084-1097.