The Plasmodium falciparum rhoptry protein RhopH3 plays essential roles in host cell invasion and nutrient uptake

Merozoites of the protozoan parasite responsible for the most virulent form of malaria, Plasmodium falciparum, invade erythrocytes. Invasion involves discharge of rhoptries, specialized secretory organelles. Once intracellular, parasites induce increased nutrient uptake by generating new permeability pathways (NPP) including a Plasmodium surface anion channel (PSAC). RhopH1/Clag3, one member of the three-protein RhopH complex, is important for PSAC/NPP activity. However, the roles of the other members of the RhopH complex in PSAC/NPP establishment are unknown and it is unclear whether any of the RhopH proteins play a role in invasion. Here we demonstrate that RhopH3, the smallest component of the complex, is essential for parasite survival. Conditional truncation of RhopH3 substantially reduces invasive capacity. Those mutant parasites that do invade are defective in nutrient import and die. Our results identify a dual role for RhopH3 that links erythrocyte invasion to formation of the PSAC/NPP essential for parasite survival within host erythrocytes.

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Plasmodium falciparum parasites deploy RhopH2 into the host erythrocyte to obtain nutrients, grow and replicate

eLife ◽

10.7554/elife.23217 ◽

2017 ◽

Vol 6 ◽

Cited By ~ 49

Author(s):

Natalie A Counihan ◽

Scott A Chisholm ◽

Hayley E Bullen ◽

Anubhav Srivastava ◽

Paul R Sanders ◽

...

Keyword(s):

Plasmodium Falciparum ◽

De Novo ◽

Parasite Growth ◽

Toxic Waste ◽

De Novo Synthesis ◽

Parasite Survival ◽

Cell Remodeling ◽

Causative Agents ◽

New Permeability Pathways ◽

Rhoptry Protein

Plasmodium falciparum parasites, the causative agents of malaria, modify their host erythrocyte to render them permeable to supplementary nutrient uptake from the plasma and for removal of toxic waste. Here we investigate the contribution of the rhoptry protein RhopH2, in the formation of new permeability pathways (NPPs) in Plasmodium-infected erythrocytes. We show RhopH2 interacts with RhopH1, RhopH3, the erythrocyte cytoskeleton and exported proteins involved in host cell remodeling. Knockdown of RhopH2 expression in cycle one leads to a depletion of essential vitamins and cofactors and decreased de novo synthesis of pyrimidines in cycle two. There is also a significant impact on parasite growth, replication and transition into cycle three. The uptake of solutes that use NPPs to enter erythrocytes is also reduced upon RhopH2 knockdown. These findings provide direct genetic support for the contribution of the RhopH complex in NPP activity and highlight the importance of NPPs to parasite survival.

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Author response: The Plasmodium falciparum rhoptry protein RhopH3 plays essential roles in host cell invasion and nutrient uptake

10.7554/elife.23239.017 ◽

2017 ◽

Author(s):

Emma S Sherling ◽

Ellen Knuepfer ◽

Joseph A Brzostowski ◽

Louis H Miller ◽

Michael J Blackman ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Host Cell ◽

Nutrient Uptake ◽

Cell Invasion ◽

Author Response ◽

Host Cell Invasion ◽

Rhoptry Protein

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Bioinformatic Identification of Peptidomimetic-Based Inhibitors against Plasmodium falciparum Antigen AMA1

Malaria Research and Treatment ◽

10.1155/2014/642391 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Asrar Alam

Keyword(s):

Plasmodium Falciparum ◽

Structural Similarity ◽

Apical Membrane Antigen 1 ◽

Lead Compounds ◽

Hydrophobic Groove ◽

Erythrocyte Invasion ◽

Binding Residues ◽

Domain I ◽

Rhoptry Protein ◽

Rhoptry Neck Protein

Plasmodium falciparum apical membrane antigen 1 (PfAMA1) is a valuable vaccine candidate and exported on the merozoite surface at the time of erythrocyte invasion. PfAMA1 interacts with rhoptry neck protein PfRON2, a component of the rhoptry protein complex, which forms the tight junction at the time of invasion. Phage display studies have identified a 15-residue (F1) and a 20-residue (R1) peptide that bind to PfAMA1 and block the invasion of erythrocytes. Cocrystal structures of central region of PfAMA1 containing disulfide-linked clusters (domains I and II) with R1 peptide and a peptide derived from PfRON2 showed strong structural similarity in binding. The peptides bound to a hydrophobic groove surrounded by domain I and II loops. In this study, peptidomimetics based on the crucial PfAMA1-binding residues of PfRON2 peptide have been identified. Top 5 peptidomimetics when checked for their docking on the region of PfAMA1 encompassing the hydrophobic groove were found to dock on the groove. Drug-like molecules having structural similarity to the top 5 peptidomimetics were identified based on their binding ability to PfAMA1 hydrophobic groove in blind docking. These inhibitors provide potential lead compounds, which could be used in the development of antimalarials targeting PfAMA1.

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Decision letter: The Plasmodium falciparum rhoptry protein RhopH3 plays essential roles in host cell invasion and nutrient uptake

10.7554/elife.23239.016 ◽

2017 ◽

Keyword(s):

Plasmodium Falciparum ◽

Host Cell ◽

Nutrient Uptake ◽

Cell Invasion ◽

Host Cell Invasion ◽

Rhoptry Protein

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Identification of a Novel RAMA/RON3 Rhoptry Protein Complex in Plasmodium falciparum Merozoites

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2020.605367 ◽

2021 ◽

Vol 10 ◽

Author(s):

Daisuke Ito ◽

Jun-Hu Chen ◽

Eizo Takashima ◽

Tomoyuki Hasegawa ◽

Hitoshi Otsuki ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Monoclonal Antibodies ◽

Molecular Mass ◽

Protein Complex ◽

Protein Complexes ◽

Parasite Development ◽

Erythrocyte Invasion ◽

Liquid Chromatography Tandem Mass ◽

Associated Proteins ◽

Rhoptry Protein

Malaria causes a half a million deaths annually. The parasite intraerythrocytic lifecycle in the human bloodstream is the major cause of morbidity and mortality. Apical organelles of merozoite stage parasites are involved in the invasion of erythrocytes. A limited number of apical organellar proteins have been identified and characterized for their roles during erythrocyte invasion or subsequent intraerythrocytic parasite development. To expand the repertoire of identified apical organellar proteins we generated a panel of monoclonal antibodies against Plasmodium falciparum schizont-rich parasites and screened the antibodies using immunofluorescence assays. Out of 164 hybridoma lines, 12 clones produced monoclonal antibodies yielding punctate immunofluorescence staining patterns in individual merozoites in late schizonts, suggesting recognition of merozoite apical organelles. Five of the monoclonal antibodies were used to immuno-affinity purify their target antigens and these antigens were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Two known apical organelle protein complexes were identified, the high-molecular mass rhoptry protein complex (PfRhopH1/Clags, PfRhopH2, and PfRhopH3) and the low-molecular mass rhoptry protein complex (rhoptry-associated proteins complex, PfRAP1, and PfRAP2). A novel complex was additionally identified by immunoprecipitation, composed of rhoptry-associated membrane antigen (PfRAMA) and rhoptry neck protein 3 (PfRON3) of P. falciparum. We further identified a region spanning amino acids Q221-E481 within the PfRAMA that may associate with PfRON3 in immature schizonts. Further investigation will be required as to whether PfRAMA and PfRON3 interact directly or indirectly.

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Faculty Opinions recommendation of Evidence for the involvement of Plasmodium falciparum proteins in the formation of new permeability pathways in the erythrocyte membrane.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1009278.373831 ◽

2006 ◽

Author(s):

Roberto Docampo

Keyword(s):

Plasmodium Falciparum ◽

Erythrocyte Membrane ◽

New Permeability Pathways

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Metalloaminopeptidases of the Protozoan Parasite Plasmodium falciparum as Targets for the Discovery of Novel Antimalarial Drugs

Journal of Medicinal Chemistry ◽

10.1021/acs.jmedchem.0c01721 ◽

2021 ◽

Vol 64 (4) ◽

pp. 1763-1785

Author(s):

Belinda Mills ◽

R. Elwyn Isaac ◽

Richard Foster

Keyword(s):

Plasmodium Falciparum ◽

Protozoan Parasite ◽

Antimalarial Drugs ◽

Parasite Plasmodium ◽

Parasite Plasmodium Falciparum

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Toxoplasma LIPIN is essential in channeling host lipid fluxes through membrane biogenesis and lipid storage

Nature Communications ◽

10.1038/s41467-021-22956-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Sheena Dass ◽

Serena Shunmugam ◽

Laurence Berry ◽

Christophe-Sebastien Arnold ◽

Nicholas J. Katris ◽

...

Keyword(s):

Fatty Acids ◽

Phosphatidic Acid ◽

De Novo ◽

Lipid Synthesis ◽

Parasite Development ◽

Membrane Biogenesis ◽

Membrane Phospholipids ◽

Phosphatidic Acid Phosphatase ◽

Intracellular Parasites ◽

Parasite Survival

AbstractApicomplexa are obligate intracellular parasites responsible for major human diseases. Their intracellular survival relies on intense lipid synthesis, which fuels membrane biogenesis. Parasite lipids are generated as an essential combination of fatty acids scavenged from the host and de novo synthesized within the parasite apicoplast. The molecular and metabolic mechanisms allowing regulation and channeling of these fatty acid fluxes for intracellular parasite survival are currently unknown. Here, we identify an essential phosphatidic acid phosphatase in Toxoplasma gondii, TgLIPIN, as the central metabolic nexus responsible for controlled lipid synthesis sustaining parasite development. Lipidomics reveal that TgLIPIN controls the synthesis of diacylglycerol and levels of phosphatidic acid that regulates the fine balance of lipids between storage and membrane biogenesis. Using fluxomic approaches, we uncover the first parasite host-scavenged lipidome and show that TgLIPIN prevents parasite death by ‘lipotoxicity’ through effective channeling of host-scavenged fatty acids to storage triacylglycerols and membrane phospholipids.

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