Adherens junctions balance stability and motility: from cell morphogenesis to neural tissue patterning.

Abstract

Adherens junctions are cellular contact sites that organize epithelial tissues and play well-characterized roles in the coordination of cell collectives. Intercellular contacts are mediated by cadherin- or nectin-based adhesion and intracellularly linked to the actin cytoskeleton via the molecular scaffolds catenin and afadin. In this review, we discuss the mechanisms and roles of these molecular scaffolds for cellular morphogenesis and collective cell behaviour with a focus on neural tissue patterning. We discuss the molecular mechanisms in the conceptual framework of two often opposing, but complementary demands on adherens junctions in developing neural tissues: stability through 'supracellular' cytoskeletal linkage across cells versus local, dynamically adhesive cellular interactions in morphogenesis. Molecular scaffolds mediate localization, mechanosensitive adhesion and the regulation of cytoskeleton tension in both mechanistic contexts. These complementary mechanisms allow for collective behaviour that has predominantly been characterized for the patterning of tissues consisting of cell bodies, but was recently shown to also underlie the patterning of an epithelial-like tissue made entirely of neuronal growth cones. Molecular scaffolding of adherens junctions thereby contributes to patterning mechanisms that may apply to diverse tissue types.