Non-morphogenic effect of Sonic Hedgehog on gastric H,K-ATPase activity.

In the stomach, Sonic Hedgehog (Shh) is highly expressed in gastric parietal cells, and acts as a morphogen in early development of the organ. Here, we found that the cleaved N-terminal fragment of Shh (Shh-N) was abundantly expressed in hog gastric vesicles derived from the apical membrane of parietal cells. Interestingly, Shh-N recombinant significantly decreased K-dependent ATP-hydrolyzing activity, which is sensitive to an inhibitor of H,K-ATPase (SCH28080), in hog gastric tubulovesicles and membrane fractions of the H,K-ATPase-expressing cells. In the living cells, Shh-N recombinant inhibited the SCH28080-sensitive Rb-uptake. Together, Shh-N may directly bind to extracellular side of H,K-ATPase, and negatively regulates the pump activity. This is the first report to explore non-morphogenic property of Shh on ion transporters.