The apical membrane of apical progenitors (APs) in the developing mammalian cortex is involved in cell-cell and cell-extracellular matrix (ECM) adhesion events that maintain the integrity of the developing neuroepithelium. Apical adhesion is important for several aspects of neural development but its regulation is poorly understood. Here (), Alice Davy and colleagues investigate the function of ephrin B1, a cell-surface protein that activates cellular signalling on binding ephrin receptors (via reverse signalling), in the morphogenesis of the developing mouse cortex. The researchers report that some Efnb1-deficient embryos display exencephaly and exhibit morphological alterations of the neuroepithelium that suggest defects in neural tube closure. Ephrin B1 is required in APs to maintain apical adhesion, they report, and ephrin B1 reverse signalling controls integrin-based cell-ECM apical adhesion through inhibition of ADP-ribosylation factor 6. These results suggest that ephrin B1 maintains the apical adhesion of APs during cortical development, a function that is essential for neural tube morphogenesis.
