Luminal signaling: it's what's on the inside that counts.

ABSTRACT

During organogenesis, FGFs are diffusible communication signals that allow cells to coordinate morphogenesis and establish tissue architecture. Recently in Nature, Durdu et al. (2014) show that epithelial cell clusters secrete FGFs into a microlumen, restricting FGF localization so that participating cells coordinate differentiation and collective migration via luminal signaling.