Lenz-Majewski mutations in <i>PTDSS1</i> affect phosphatidylinositol 4-phosphate metabolism at ER-PM and ER-Golgi junctions

Abstract

Significance Phosphatidylserine (PS) is synthesized in the endoplasmic reticulum by PS synthase enzymes, but most of the PS is found in the inner leaflet of the plasma membrane. The importance of the present findings is that they uncover a critical connection between PI4P turnover and PS transport and demonstrate that uncontrolled PS synthesis as seen in Lenz-Majewski syndrome patients has deleterious consequences to cells affecting other lipids and not just PS.