Prostasin is a membrane-anchored serine protease, expressed in the epithelium of multiple organs and known to regulate the epithelial sodium channel. In several studies it has been linked to pre-eclampsia.

In mice, prostasin deficiency leads to placental malfunction and embryonal lethality from day 13.5 onwards. To understand the consequences of deleting prostasin in the placenta, we quantitatively compared placenta lysates of wildtypeand prostasin deficient mice by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in conjunction with stable isotope labeling. Furthermore we were interested in prostain’s substrates and performed “terminal amine isotopic labeling of substrates” (TAILS), an N-terminomic technique for the identification and quantification of native and proteolytically generated protein N-termini.

Prostasin deficiency leads to alterations in the abundance of proteins involved in angiogenesis, placental development and several members of the carcinoembryonic antigen family. TAILS revealed that Prostasin affects a multitude of proteolytic processing sites. To underline these findings validations by immunohistochemistry and western blot analysis will be performed.