Molecule allows Malaria Parasite to Commander RBCs.

Two groups of HHMI scientists have identified a critical enzyme that allows the malaria-causing parasite, Plasmodium falciparum to take over and thrive in human RBCs.

Enzyme plasmepsin V is a Gate-Keeper inside the malaria parasite that allows the parasite to export its own proteins into a human RBCs.

Once PMV opens the gate into RBCs, the parasite moves hundreds of the proteins into cells, which remodels it and eventually, annihilates it.

PMV scans the proteins inside the parasite for a molecular barcode called the PEXEL motif. When PMV detects that signal, it trims off the protein's end and then feeds the processed protein into a molecular machine called a Translocon, which pushes the protein into the RBCs. After parasite protein entered into human RBCs, they begin destroying oxygen-carrying hemoglobin and disfigure the cell surface so that the blood cells stick to blood vessels rather than circulating freely.

# This allows the parasite to use the RBCs as a shield to hide from the host immune system. All the mischief causes the fatigue, fever, neurological symptoms characteristic of this sometimes fatal form of malaria.

Marletta's lab at the University of California, Berkeley showed that proteins with a PEXEL motif were cleaved by an unknown factor housed inside a network of tubules inside the parasite called the Endoplasmic reticulum.

Researchers also knew that protease inhibitor drugs used to treat human immunodeficiency virus were moderately effective against malaria. those drugs block a class of protein cutting enzymes called aspartyl protease. Based on these hints., "Cowman" compiled a list of candidate Pf aspartyl proteases. PMV was essential for malarial parasites' survival.

Trick parasite by engineering protein that displays a "Faux-PEXEL" barcode, but protein somehow knew it was clipped by PMV and not by an imposter, that protein was not exported.

This indicates that PMV clips a protein it immediately hands the protein off to a set of dedicated ushers who guide it through the translocon into RBCs.