In the non-CF lung, Spns2 is expressed in tunica media (thin arrows) of vascular structures, in muscularis mucosae (asterisks) of distal bronchiole (Figure 6A), and, to a lesser extent, in the cytoplasm of ciliated respiratory cells (thick arrows) (Figure 6A1, magnification of the inset in 6A). Here, SPNS2 is linked to cystic fibrosis.