Plasmodium falciparum Rab1A Localizes to Rhoptries in Schizonts.

David Morse,Gordon Langsley,Ming Kalanon,Wesley Webster,Geoffrey I Mcfadden

doi:10.1371/journal.pone.0158174

Abstract

Over-expression of a GFP-PfRab1A fusion protein in Plasmodium falciparum schizonts produces a punctate pattern of fluorescence typical of rhoptries, secretory organelles involved in host cell invasion. The GFP-positive bodies were purified by a combination of differential and density gradient centrifugation and their protein content determined by MS/MS sequencing. Consistent with the GFP rhoptry-like pattern of transgenic parasites, four of the 19 proteins identified have been previously described to be rhoptry-associated and another four are ER or ER-associated proteins. Confirmation that GFP-PfRab1A decorates rhoptries was obtained by its co-localization with Rap1 and Ron4 in late phase schizonts. We conclude that PfRab1A potentially regulates vesicular traffic from the endoplasmic reticulum to the rhoptries in Apicomplexa parasites.

Highlights

The apicomplexan parasite Plasmodium falciparum is a causal agent of human malaria
Called the apical complex, a group of three morphologically distinct compartments called the rhoptries [4], micronemes [5], and dense granules [6] are responsible for invasion of blood cells and have a defined choreography of action during the process of host cell invasion [7]
To assess the possible role of PfRab1A, we have examined the distribution of a GFP-PfRab1A fusion protein in red blood cell stages of P. falciparum

Summary

Introduction

The apicomplexan parasite Plasmodium falciparum is a causal agent of human malaria. This protist is an important health concern, as according to the 2015 World Health Organization report, it is responsible for roughly 438,000 fatalities yearly worldwide. The function of PfRab1A has not been extensively studied [13], but in the related apicomplexan Toxoplasma gondii, Nterminal myc-tagged TgRab1A has a punctate appearance and a partial co-localization with markers for an micronemal/endosomal-like compartment, thought to be an intermediate between the Golgi and the apical secretory organelles [22]. To assess the possible role of PfRab1A, we have examined the distribution of a GFP-PfRab1A fusion protein in red blood cell stages of P. falciparum.

Results

Conclusion