Protein O-Fucosyltransferase 2 Is Not Essential for Plasmodium berghei Development.

Silvia Sanz,Bernadette Hritzo,Abhai Tripathi,Luis Izquierdo,Thomas S Churcher,Timothy Hamerly,Garima Verma,Rhoel R Dinglasan,Eleonora Aquilini,João A Rodrigues,Marta Machado,Rebecca E Tweedell

doi:10.3389/fcimb.2019.00238

Abstract

Thrombospondin type I repeat (TSR) domains are commonly O-fucosylated by protein O-fucosyltransferase 2 (PoFUT2), and this modification is required for optimal folding and secretion of TSR-containing proteins. The human malaria parasite Plasmodium falciparum expresses proteins containing TSR domains, such as the thrombospondin-related anonymous protein (TRAP) and circumsporozoite surface protein (CSP), which are O-fucosylated. TRAP and CSP are present on the surface of sporozoites and play essential roles in mosquito and human host invasion processes during the transmission stages. Here, we have generated PoFUT2 null-mutant P. falciparum and Plasmodium berghei (rodent) malaria parasites and, by phenotyping them throughout their complete life cycle, we show that PoFUT2 disruption does not affect the growth through the mosquito stages for both species. However, contrary to what has been described previously by others, P. berghei PoFUT2 null mutant sporozoites showed no deleterious motility phenotypes and successfully established blood stage infection in mice. This unexpected result indicates that the importance of O-fucosylation of TSR domains may differ between human and RODENT malaria parasites; complicating our understanding of glycosylation modifications in malaria biology.

Highlights

Malaria is one of the most important human parasitic diseases, causing ∼219 million new cases and more than 400,000 deaths every year (WHO, 2018)
To study the function of protein O-fucosyltransferase 2 (PoFUT2) in Plasmodium parasites, we knocked out this gene in the human malaria parasite P. falciparum
P. falciparum PoFUT2 (Pf PoFUT2) was disrupted by double crossover recombination using a targeting construct that replaced the gene with a hu-dhfr selection cassette in the P. falciparum NF54 line, the same parasite line used by Lopaticki et al (Lopaticki et al, 2017)

Summary

Introduction

Malaria is one of the most important human parasitic diseases, causing ∼219 million new cases and more than 400,000 deaths every year (WHO, 2018). It is caused by a protozoan apicomplexan parasite of the genus Plasmodium, with Plasmodium falciparum regarded as the deadliest species. Plasmodium parasites are transmitted by female Anopheles mosquitoes. After the bite of an infected mosquito, motile sporozoites are injected into the human dermis; from there, they travel through blood vessels to the liver and infect hepatocytes. A week later, the infected hepatocyte ruptures and releases merozoites that reach the blood circulation and invade erythrocytes initiating cyclical asexual reproduction. A small percentage of blood stage parasites become sexually committed cells

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