Magic touch: how does cell-cell adhesion trigger actin assembly?

The formation of cadherin-mediated cell-cell junctions is accompanied by a profound remodeling of the actin cytoskeleton. The Arp2/3 complex and its activator cortactin drive the assembly of branching actin-filament arrays, and formin-1 promotes the nucleation of non-branching actin filaments. Recruitment of these actin nucleators to nascent adhesions, formation of the links between them and the cytoplasmic cadherin domain, and triggering of their actin-polymerizing functions are vital steps in the development of cell-cell junctions. In this article, I discuss recent results showing that proteins involved in the regulation of actin polymerization have crucial roles in the development and maintenance of the cadherin junctions.