Combining structural biology and genetics to understand the function of a multi-gene family expanded in neglected human malaria parasites

The Tryptophan Rich Antigens (TRAgs) are found in all Plasmodium species, but are significantly expanded in the Plasmodium subgenus, implying that they have a critical function in these parasite species, including both P. vivax, the cause of most malaria in Latin America, and P. knowlesi, a zoonotic parasite that causes thousands of cases of malaria each year in Southeast Asia. The function of TRAgs has never been explored in detail. Recently experiments have solved the structure of the conserved trypotphan/threonine rich C-terminal domain which defines the TRAg family. This revealed homology to the lipid-binding BAR domain, and we have confirmed that multiple P. vivax and P. knowlesi TRAg domains are able to directly interact with lipids. This presents for the first time a unifying hypothesis for TRAg domain function, that they interact with lipids to modulate cell membranes, and may play roles in host-parasite interactions both during and after the invasion of human erythrocytes. Biochemical and structural biology tools will be used to explore the extent of and structural basis for TRAg-lipid specificity. Antibody generation and epitope tagging will be combined to establish the location of multiple TRAgs using advanced microscopy. Finally, CRISPR/Cas9 editing will be used to carry out standard, conditional and combinatorial knockout approaches to delete individual/combinations of TRAgs and explore the impact on growth and invasion. This will be the first systematic study of TRAgs in the Plasmodium subgenus and will provide critical information about the blood-stage biology of these neglected human malaria parasites.

Project details

Basic Science

Mar 2024 — Feb 2027

$1.12M

United Kingdom

Plasmodium knowlesi