Close encounters of the RNAi kind: the silencing life of the adherens junctions.

The adherens junction has been historically considered an essential structural component of epithelial tissues. Although primarily discussed as targets of signaling pathways responsible for cell fate and tissue remodeling, they have also emerged as critical signaling regulators in developmental processes or in disease progression. The recent discovery of a functional localized RNA interference (RNAi) machinery at epithelial adherens junctions revealed a new layer of signaling regulation that is directly associated with the structure itself. This and other findings also indicate that our view of the subcellular localization of RNAi requires revisiting. A number of questions emerge regarding the physiological role and the modes of regulation of the junctional RNAi machinery, pointing towards new directions of investigation.