Adherens junction domains are split by asymmetric division of embryonic neural stem cells

Investigating the mechanisms controlling the asymmetric division of neocortical progenitors that generate neurones in the mammalian brain is crucial for understanding the abnormalities of cortical development. Partitioning of fate determinants is a key instructive step and components of the apical junctional complex (adherens junctions), including the polarity proteins PAR3 and aPKC as well as adhesion molecules such as N-cadherin, have been proposed to be candidate determinants. In this study, however, we found no correlation between the partitioning of N-cadherin and fate determination. Rather, we show that adherens junctions comprise three membrane domains, and that during asymmetrical division these are split such that both daughters retain the adhesive proteins that control cell position, but only one daughter inherits the polarity proteins along with the apical membrane. This provides a molecular explanation as to how both daughters remain anchored to the ventricular surface after mitosis, while adopting different fates.