Dbnl and β-catenin promote pro-N-cadherin processing to maintain apico-basal polarity

• Adherens junctions (AJs) concentrate at the sup-apical region of neural stem cells and they are critical to maintain apico-basal polarity as these cells differentiate. Herrera et al, have recently shown that Dbnl and β-catenin cooperate to promote pro-N-cadherin processing, facilitating AJs assemble during neural tube development.

The neural tube forms when neural stem cells (NSCs) arrange into a pseudostratified, single-cell layered epithelium, with a marked apico-basal polarity, and in which adherens junctions (AJs) concentrate in the sub-apical domain. We previously reported that sustained β-catenin expression promotes the formation of enlarged apical complexes (ACs), enhancing apico-basal polarity, although the mechanism through which this occurs remained unclear. Here we show that β-catenin interacts with phosphorylated pro-N-cadherin early in its transit through the Golgi apparatus, promoting propeptide excision and the final maturation of N-cadherin. We describe a new β-catenin-dependent interaction of N-cadherin with Debrin-like (Dbnl), an actin binding protein that is involved in anterograde Golgi trafficking of proteins. Notably, Dbnl knockdown led to pro-N-cadherin accumulation and limited AJ formation. In brief, we demonstrate that Dbnl and β-catenin assist in the maturation of Pro-N-cadherin, which is critical for AJ formation and for the recruitment AC components like aPKC, and consequently, for the maintenance of apico-basal polarity.

Reference:

Herrera, A., Menendez, A., Torroba, B., Ochoa, A., and Pons, S. (2021). Dbnl and β-catenin promote pro-N-cadherin processing to maintain apico-basal polarity. The Journal of cell biology 220. 10.1083/jcb.202007055.

DOI:https://doi.org/10.1083/jcb.202007055

Schematic representation of the process by which β-catenin and Dbnl cooperate to promote N-cadherin maturation in the neural precursors from chicken neural tube. ER, endoplasmic reticulum; TGN, trans golgi network.