A Comprehensive Subcellular Atlas of the Toxoplasma Proteome via hyperLOPIT Provides Spatial Context for Protein Functions

Konstantin Barylyuk,Ludek Koreny,Huiling Ke,Simon Butterworth,Oliver M Crook,Imen Lassadi,Vipul Gupta,Eelco Tromer,Tobias Mourier,Tim J Stevens,Lisa M Breckels,Arnab Pain,Kathryn S Lilley,Ross F Waller

doi:10.1016/j.chom.2020.09.011

Abstract

SummaryApicomplexan parasites cause major human disease and food insecurity. They owe their considerable success to highly specialized cell compartments and structures. These adaptations drive their recognition, nondestructive penetration, and elaborate reengineering of the host’s cells to promote their growth, dissemination, and the countering of host defenses. The evolution of unique apicomplexan cellular compartments is concomitant with vast proteomic novelty. Consequently, half of apicomplexan proteins are unique and uncharacterized. Here, we determine the steady-state subcellular location of thousands of proteins simultaneously within the globally prevalent apicomplexan parasite Toxoplasma gondii. This provides unprecedented comprehensive molecular definition of these unicellular eukaryotes and their specialized compartments, and these data reveal the spatial organizations of protein expression and function, adaptation to hosts, and the underlying evolutionary trajectories of these pathogens.

Highlights

Apicomplexa is a phylum of highly adapted unicellular eukaryotes specialized for intracellular parasitism in animals (Votypka et al, 2017)
Even the locations of proteins of predicted function based on conserved sequences in other organisms are largely untested in apicomplexans. We address this critical deficiency in apicomplexan biology, and the wider need to understand the compositional architecture of these parasites and its dynamics, by applying the spatial proteomic method hyperplexed localization of organelle proteins by isotope tagging (Christoforou et al, 2016; Mulvey et al, 2017) to capture the steady-state location of thousands of proteins in the apicomplexan T. gondii
Whole-Cell Biochemical Fractionation of Toxoplasma gondii Extracellular Tachyzoites To determine if the steady-state subcellular locations of thousands of proteins could be simultaneously captured in apicomplexans, we adapted the hyperLOPIT method for whole-cell spatial proteomics to Toxoplasma gondii extracellular tachyzoites, the parasite form that is primed for host-cell invasion

Summary

Introduction

Apicomplexa is a phylum of highly adapted unicellular eukaryotes specialized for intracellular parasitism in animals (Votypka et al, 2017). Many apicomplexans cause devastating diseases in humans and livestock. Malaria, caused by Plasmodium spp., results in over 400,000 deaths and 200 million clinical cases annually, with 3.2 billion people at risk (World Health Organization, 2018). Cryptosporidiosis (Cryptosporidium spp.) is the second leading cause of fatal infant diarrhea affecting 800,000 annually (Kotloff et al, 2013; Striepen, 2013). The economic damage of disease in livestock caused by apicomplexans is estimated in billions of US dollars annually (Rashid et al, 2019). Together these pathogens have a major effect on global health and prosperity, disproportionately affecting developing world regions

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Discussion

Conclusion