Structural basis of erythrocyte invasion by Plasmodium falciparum

Malaria remains one of the most devastating infectious diseases of humanity, affecting over 220 million people and causing an estimated 405,000 deaths in 2018, primarily in low-income African countries. The causative agent responsible for the majority of malaria-associated deaths is Plasmodium falciparum, a unicellular eukaryotic parasite belonging to the Apicomplexa phylum. The symptoms of malaria occur when the parasite replicates within the blood of an infected individual. Invasion of erythrocytes by the merozoite form of the parasite is essential for its replication and for the development of the disease. These parasite stages are therefore the focus of pro-active efforts to find novel approaches to pre-empt the rise of resistance against currently used treatments. Preventing invasion is a promising strategy to stop malaria.

The MJ is an indispensable protein complex formed at the interface of parasite and erythrocyte plasma membranes. Specifically, this project investigate the molecular assembly of the rhoptry neck protein (RON) complex, a central but elusive component of the MJ. This parasite-derived complex is inserted into the host cell plasma membrane, where it interacts with the host cytoskeleton. It also binds to parasite surface proteins, which link it, through motor proteins, to the parasite inner membrane complex. Relative movement of these components drives parasite invasion. Surprisingly little is known about the assembly of the RON complex or its function during the invasion process. The goal of this fellowship is to elucidate the structure and molecular architecture of the RON complex to provide a better understanding of the erythrocyte invasion by P. falciparum. To achieve this, the power of CRISPR gene editing technology and cryo-electron microscopy will be combined which will allow the study of native RON complex extracted from merozoites.

This research will:•Genetically engineer P. falciparum using a combination of the Cre-recombinase and CRISPR/Cas9 systems, allowing tagging components of the RON complex.•Extract and purify the native RON complex directly from P. falciparum merozoites.•Study the composition of the complex using modern mass spectrometry and bioinformatics. •Investigate the structure and molecular architecture of the RON complex by state-of-the-art single particle cryo-electron microscopy. •In parallel, and as contingency, express individual recombinant components of the RON complex in HEK293 cells, and study their structures and interactions using X-ray crystallography and a range of complimentary biophysical techniques. This combination of studies will allows to elucidate, for the first time, the structure and architecture of the RON complex. Understanding the molecular working mechanism will provide unprecedented molecular insight into erythrocyte invasion by P. falciparum and is thus of high significance for the development of novel therapeutic approaches against malaria.

Project details

Basic Science

Jan 2022 — Dec 2023

$130,408

United Kingdom