Fundamental malaria parasite function discovered

A team of researchers led at the University of Notre Dame has made a fundamental discovery in understanding how malaria parasites target proteins to the surface of red blood cells. Malaria is caused by a parasite that infects red cells in the blood. Once inside the cell, the parasite exports proteins beyond its own plasma membrane border into the blood cell. In all cells, proteins are made in a specialized cell compartment called the endoplasmic reticulum (ER). Researchers discovered that for host-targeted malaria proteins the very first step is binding to the lipid phosphatidylinositol 3-phosphate (PI(3)P) in the ER. This was surprising for two reasons. Previous studies suggested an enzyme that released the proteins into the ER was also the export mechanism. However, the PI(3)P lipid is the gate keeper to control export. Further, in human cells, the lipid PI(3)P is not usually found within the ER membrane but rather is exposed to the cellular cytoplasm.