1
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Leveraging a Fluorescent Fatty Acid Probe to Discover Cell-Permeable Inhibitors of Plasmodium falciparum Glycerolipid Biosynthesis. Microbiol Spectr 2022; 10:e0245622. [PMID: 36314974 PMCID: PMC9769509 DOI: 10.1128/spectrum.02456-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A sensitive and quantitative fluorescence-based approach is presented for characterizing fatty acid acquisition and lipid biosynthesis by asexually replicating, intraerythrocytic Plasmodium falciparum. We show that a BODIPY-containing, green-fluorescent fatty acid analog is efficiently and rapidly incorporated into parasite neutral lipids and phospholipids. Prelabeling with a red-fluorescent ceramide analog permits normalization and enables reliable quantitation of glycerolipid labeling. Inhibition of lipid labeling by competition with natural fatty acids and by acyl-coenzyme A synthetase and diacylglycerol acyltransferase inhibitors demonstrates that the fluorescent fatty acid probe is acquired, activated, and transferred to lipids through physiologically-relevant pathways. To assess its utility in discovering small molecules that block parasite lipid biosynthesis, the lipid labeling assay was used to screen a panel of mammalian lipase inhibitors and a selection of compounds from the "Malaria Box" anti-malarial collection. Several compounds were identified that inhibited the incorporation of the fluorescent fatty acid probe into lipids in cultured parasites at low micromolar concentrations. Two contrasting profiles of suppression of neutral lipid and phospholipid synthesis were observed, which implies the inhibition of distinct pathways. IMPORTANCE The human malaria parasite Plasmodium falciparum relies on fatty acid scavenging to supply this essential precursor of lipid synthesis during its asexual replication cycle in human erythrocytes. This dependence on host fatty acids represents a potential vulnerability that can be exploited to develop new anti-malarial therapies. The quantitative experimental approach described here provides a platform for simultaneously interrogating multiple facets of lipid metabolism- fatty acid uptake, fatty acyl-CoA synthesis, and neutral lipid and phospholipid biosynthesis- and of identifying cell-permeable inhibitors that are active in situ.
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2
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Quadt KA, Smyrnakou X, Frischknecht F, Böse G, Ganter M. Plasmodium falciparum parasites exit the infected erythrocyte after haemolysis with saponin and streptolysin O. Parasitol Res 2020; 119:4297-4302. [PMID: 33089360 DOI: 10.1007/s00436-020-06932-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 10/11/2020] [Indexed: 11/28/2022]
Abstract
Malaria is caused by unicellular parasites of the genus Plasmodium, which reside in erythrocytes during the clinically relevant stage of infection. To separate parasite from host cell material, haemolytic agents such as saponin are widely used. Previous electron microscopy studies on saponin-treated parasites reported both, parasites enclosed by the erythrocyte membrane and liberated from the host cell. These ambiguous reports prompted us to investigate haemolysis by live-cell time-lapse microscopy. Using either saponin or streptolysin O to lyse Plasmodium falciparum-infected erythrocytes, we found that ring-stage parasites efficiently exit the erythrocyte upon haemolysis. For late-stage parasites, we found that only approximately half were freed, supporting the previous electron microscopy studies. Immunofluorescence imaging indicated that freed parasites were surrounded by the parasitophorous vacuolar membrane. These results may be of interest for future work using haemolytic agents to enrich for parasite material.
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Affiliation(s)
- Katharina A Quadt
- Zendia GmbH, Rummler 5, 48324, Sendenhorst, Germany.,Parasitology, Centre for Infectious Diseases, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Xanthoula Smyrnakou
- Zendia GmbH, Rummler 5, 48324, Sendenhorst, Germany.,Parasitology, Centre for Infectious Diseases, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Centre for Infectious Diseases, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany.,German Centre for Infection Research, Heidelberg Division, Heidelberg, Germany
| | - Guido Böse
- Zendia GmbH, Rummler 5, 48324, Sendenhorst, Germany.
| | - Markus Ganter
- Zendia GmbH, Rummler 5, 48324, Sendenhorst, Germany. .,Parasitology, Centre for Infectious Diseases, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany.
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3
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Nessel T, Beck JM, Rayatpisheh S, Jami-Alahmadi Y, Wohlschlegel JA, Goldberg DE, Beck JR. EXP1 is required for organisation of EXP2 in the intraerythrocytic malaria parasite vacuole. Cell Microbiol 2020; 22:e13168. [PMID: 31990132 DOI: 10.1111/cmi.13168] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/04/2019] [Accepted: 01/07/2020] [Indexed: 12/17/2022]
Abstract
Intraerythrocytic malaria parasites reside within a parasitophorous vacuole membrane (PVM) that closely overlays the parasite plasma membrane. Although the PVM is the site of several transport activities essential to parasite survival, the basis for organisation of this membrane system is unknown. Here, we performed proximity labeling at the PVM with BioID2, which highlighted a group of single-pass integral membrane proteins that constitute a major component of the PVM proteome but whose function remains unclear. We investigated EXP1, the longest known member of this group, by adapting a CRISPR/Cpf1 genome editing system to install the TetR-DOZI-aptamers system for conditional translational control. Importantly, although EXP1 was required for intraerythrocytic development, a previously reported in vitro glutathione S-transferase activity could not account for this essential EXP1 function in vivo. EXP1 knockdown was accompanied by profound changes in vacuole ultrastructure, including apparent increased separation of the PVM from the parasite plasma membrane and formation of abnormal membrane structures. Furthermore, although activity of the Plasmodium translocon of exported proteins was not impacted by depletion of EXP1, the distribution of the translocon pore-forming protein EXP2 but not the HSP101 unfoldase was substantially altered. Collectively, our results reveal a novel PVM defect that indicates a critical role for EXP1 in maintaining proper organisation of EXP2 within the PVM.
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Affiliation(s)
- Timothy Nessel
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa
| | - John M Beck
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa
| | - Shima Rayatpisheh
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, California
| | - Yasaman Jami-Alahmadi
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, California
| | - James A Wohlschlegel
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, California
| | - Daniel E Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University, St. Louis, Missouri
| | - Josh R Beck
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa.,Departments of Medicine and Molecular Microbiology, Washington University, St. Louis, Missouri
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4
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The parasitophorous vacuole of the blood-stage malaria parasite. Nat Rev Microbiol 2020; 18:379-391. [PMID: 31980807 DOI: 10.1038/s41579-019-0321-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2019] [Indexed: 12/31/2022]
Abstract
The pathology of malaria is caused by infection of red blood cells with unicellular Plasmodium parasites. During blood-stage development, the parasite replicates within a membrane-bound parasitophorous vacuole. A central nexus for host-parasite interactions, this unique parasite shelter functions in nutrient acquisition, subcompartmentalization and the export of virulence factors, making its functional molecules attractive targets for the development of novel intervention strategies to combat the devastating impact of malaria. In this Review, we explore the origin, development, molecular composition and functions of the parasitophorous vacuole of Plasmodium blood stages. We also discuss the relevance of the malaria parasite's intravacuolar lifestyle for successful erythrocyte infection and provide perspectives for future research directions in parasitophorous vacuole biology.
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5
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Linzke M, Yan SLR, Tárnok A, Ulrich H, Groves MR, Wrenger C. Live and Let Dye: Visualizing the Cellular Compartments of the Malaria Parasite Plasmodium falciparum. Cytometry A 2019; 97:694-705. [PMID: 31738009 DOI: 10.1002/cyto.a.23927] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 10/03/2019] [Accepted: 10/24/2019] [Indexed: 12/15/2022]
Abstract
Malaria remains one of the deadliest diseases worldwide and it is caused by the protozoan parasite Plasmodium spp. Parasite visualization is an important tool for the correct detection of malarial cases but also to understand its biology. Advances in visualization techniques promote new insights into the complex life cycle and biology of Plasmodium parasites. Live cell imaging by fluorescence microscopy or flow cytometry are the foundation of the visualization technique for malaria research. In this review, we present an overview of possibilities in live cell imaging of the malaria parasite. We discuss some of the state-of-the-art techniques to visualize organelles and processes of the parasite and discuss limitation and advantages of each technique. © 2019 International Society for Advancement of Cytometry.
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Affiliation(s)
- Marleen Linzke
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
| | - Sun Liu Rei Yan
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
| | - Attila Tárnok
- Institute for Medical Informatics, Statistics and Epidemiology, Medical Faculty, University Leipzig, D-04107, Härtelstraße 16-18, Leipzig, Germany
| | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, São Paulo, São Paulo, 05508-900, Brazil
| | - Matthew R Groves
- Structural Biology Unit, Department of Pharmacy, Faculty of Science and Engineering, University of Groningen, 9713AV, Antonius Deusinglaan 1, AV Groningen, The Netherlands
| | - Carsten Wrenger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
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6
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Liu B, Blanch AJ, Namvar A, Carmo O, Tiash S, Andrew D, Hanssen E, Rajagopal V, Dixon MW, Tilley L. Multimodal analysis of
Plasmodium knowlesi
‐infected erythrocytes reveals large invaginations, swelling of the host cell, and rheological defects. Cell Microbiol 2019; 21:e13005. [PMID: 30634201 PMCID: PMC6593759 DOI: 10.1111/cmi.13005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 12/14/2018] [Accepted: 01/08/2019] [Indexed: 02/06/2023]
Abstract
The simian parasite Plasmodium knowlesi causes severe and fatal malaria infections in humans, but the process of host cell remodelling that underpins the pathology of this zoonotic parasite is only poorly understood. We have used serial block‐face scanning electron microscopy to explore the topography of P. knowlesi‐infected red blood cells (RBCs) at different stages of asexual development. The parasite elaborates large flattened cisternae (Sinton Mulligan's clefts) and tubular vesicles in the host cell cytoplasm, as well as parasitophorous vacuole membrane bulges and blebs, and caveolar structures at the RBC membrane. Large invaginations of host RBC cytoplasm are formed early in development, both from classical cytostomal structures and from larger stabilised pores. Although degradation of haemoglobin is observed in multiple disconnected digestive vacuoles, the persistence of large invaginations during development suggests inefficient consumption of the host cell cytoplasm. The parasite eventually occupies ~40% of the host RBC volume, inducing a 20% increase in volume of the host RBC and an 11% decrease in the surface area to volume ratio, which collectively decreases the ability of the P. knowlesi‐infected RBCs to enter small capillaries of a human erythrocyte microchannel analyser. Ektacytometry reveals a markedly decreased deformability, whereas correlative light microscopy/scanning electron microscopy and python‐based skeleton analysis (Skan) reveal modifications to the surface of infected RBCs that underpin these physical changes. We show that P. knowlesi‐infected RBCs are refractory to treatment with sorbitol lysis but are hypersensitive to hypotonic lysis. The observed physical changes in the host RBCs may underpin the pathology observed in patients infected with P. knowlesi.
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Affiliation(s)
- Boyin Liu
- Department of Biochemistry and Molecular Biology Bio21 Molecular Science and Biotechnology Institute Melbourne Victoria Australia
| | - Adam J. Blanch
- Department of Biochemistry and Molecular Biology Bio21 Molecular Science and Biotechnology Institute Melbourne Victoria Australia
| | - Arman Namvar
- Department of Biomedical Engineering The University of Melbourne Melbourne Victoria Australia
| | - Olivia Carmo
- Department of Biochemistry and Molecular Biology Bio21 Molecular Science and Biotechnology Institute Melbourne Victoria Australia
| | - Snigdha Tiash
- Department of Biochemistry and Molecular Biology Bio21 Molecular Science and Biotechnology Institute Melbourne Victoria Australia
| | - Dean Andrew
- Department of Biochemistry and Molecular Biology Bio21 Molecular Science and Biotechnology Institute Melbourne Victoria Australia
| | - Eric Hanssen
- Department of Biochemistry and Molecular Biology Bio21 Molecular Science and Biotechnology Institute Melbourne Victoria Australia
- Advanced Microscopy Facility Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne Melbourne Victoria Australia
| | - Vijay Rajagopal
- Department of Biomedical Engineering The University of Melbourne Melbourne Victoria Australia
| | - Matthew W.A. Dixon
- Department of Biochemistry and Molecular Biology Bio21 Molecular Science and Biotechnology Institute Melbourne Victoria Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology Bio21 Molecular Science and Biotechnology Institute Melbourne Victoria Australia
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7
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Sherling ES, van Ooij C. Host cell remodeling by pathogens: the exomembrane system in Plasmodium-infected erythrocytes. FEMS Microbiol Rev 2017; 40:701-21. [PMID: 27587718 PMCID: PMC5007283 DOI: 10.1093/femsre/fuw016] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2016] [Indexed: 12/22/2022] Open
Abstract
Malaria is caused by infection of erythrocytes by parasites of the genus Plasmodium. To survive inside erythrocytes, these parasites induce sweeping changes within the host cell, one of the most dramatic of which is the formation of multiple membranous compartments, collectively referred to as the exomembrane system. As an uninfected mammalian erythrocyte is devoid of internal membranes, the parasite must be the force and the source behind the formation of these compartments. Even though the first evidence of the presence these of internal compartments was obtained over a century ago, their functions remain mostly unclear, and in some cases completely unknown, and the mechanisms underlying their formation are still mysterious. In this review, we provide an overview of the different parts of the exomembrane system, describing the parasitophorous vacuole, the tubovesicular network, Maurer's clefts, the caveola-vesicle complex, J dots and other mobile compartments, and the small vesicles that have been observed in Plasmodium-infected cells. Finally, we combine the data into a simplified view of the exomembrane system and its relation to the alterations of the host erythrocyte. Plasmodium parasites remodel the host erythrocyte in various ways, including the formation of several membranous compartments, together referred to as the exomembrane system, within the erythrocyte cytosol that together are key to the sweeping changes in the host cell.
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Affiliation(s)
- Emma S Sherling
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Christiaan van Ooij
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK
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8
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Nyboer B, Heiss K, Mueller AK, Ingmundson A. The Plasmodium liver-stage parasitophorous vacuole: A front-line of communication between parasite and host. Int J Med Microbiol 2017; 308:107-117. [PMID: 28964681 DOI: 10.1016/j.ijmm.2017.09.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/19/2017] [Accepted: 09/11/2017] [Indexed: 12/13/2022] Open
Abstract
The intracellular development and differentiation of the Plasmodium parasite in the host liver is a prerequisite for the actual onset of malaria disease pathology. Since liver-stage infection is clinically silent and can be completely eliminated by sterilizing immune responses, it is a promising target for urgently needed innovative antimalarial drugs and/or vaccines. Discovered more than 65 years ago, these stages remain poorly understood regarding their molecular repertoire and interaction with their host cells in comparison to the pathogenic erythrocytic stages. The differentiating and replicative intrahepatic parasite resides in a membranous compartment called the parasitophorous vacuole, separating it from the host-cell cytoplasm. Here we outline seminal work that contributed to our present understanding of the fundamental dynamic cellular processes of the intrahepatic malarial parasite with both specific host-cell factors and compartments.
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Affiliation(s)
- Britta Nyboer
- Centre for Infectious Diseases, Parasitology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Kirsten Heiss
- Centre for Infectious Diseases, Parasitology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; Centre for Infection Research (DZIF), D 69120 Heidelberg, Germany
| | - Ann-Kristin Mueller
- Centre for Infectious Diseases, Parasitology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; Centre for Infection Research (DZIF), D 69120 Heidelberg, Germany,.
| | - Alyssa Ingmundson
- Department of Molecular Parasitology, Institute of Biology, Humboldt University Berlin, Philippstrasse 13, 10115 Berlin, Germany.
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9
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The Plasmodium berghei translocon of exported proteins reveals spatiotemporal dynamics of tubular extensions. Sci Rep 2015. [PMID: 26219962 PMCID: PMC4518229 DOI: 10.1038/srep12532] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The erythrocyte is an extraordinary host cell for intracellular pathogens and requires extensive remodelling to become permissive for infection. Malaria parasites modify their host red blood cells through protein export to acquire nutrients and evade immune responses. Endogenous fluorescent tagging of three signature proteins of the Plasmodium berghei translocon of exported proteins (PTEX), heat shock protein 101, exported protein 2 (EXP2), and PTEX88, revealed motile, tubular extensions of the parasitophorous vacuole that protrude from the parasite far into the red blood cell. EXP2 displays a more prominent presence at the periphery of the parasite, consistent with its proposed role in pore formation. The tubular compartment is most prominent during trophozoite growth. Distinct spatiotemporal expression of individual PTEX components during sporogony and liver-stage development indicates additional functions and tight regulation of the PTEX translocon during parasite life cycle progression. Together, live cell imaging and correlative light and electron microscopy permitted previously unrecognized spatiotemporal and subcellular resolution of PTEX-containing tubules in murine malaria parasites. These findings further refine current models for Plasmodium-induced erythrocyte makeover.
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10
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Host erythrocyte environment influences the localization of exported protein 2, an essential component of the Plasmodium translocon. EUKARYOTIC CELL 2015; 14:371-84. [PMID: 25662767 DOI: 10.1128/ec.00228-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 01/28/2015] [Indexed: 11/20/2022]
Abstract
Malaria parasites replicating inside red blood cells (RBCs) export a large subset of proteins into the erythrocyte cytoplasm to facilitate parasite growth and survival. PTEX, the parasite-encoded translocon, mediates protein transport across the parasitophorous vacuolar membrane (PVM) in Plasmodium falciparum-infected erythrocytes. Proteins exported into the erythrocyte cytoplasm have been localized to membranous structures, such as Maurer's clefts, small vesicles, and a tubovesicular network. Comparable studies of protein trafficking in Plasmodium vivax-infected reticulocytes are limited. With Plasmodium yoelii-infected reticulocytes, we identified exported protein 2 (Exp2) in a proteomic screen of proteins putatively transported across the PVM. Immunofluorescence studies showed that P. yoelii Exp2 (PyExp2) was primarily localized to the PVM. Unexpectedly, PyExp2 was also associated with distinct, membrane-bound vesicles in the reticulocyte cytoplasm. This is in contrast to P. falciparum in mature RBCs, where P. falciparum Exp2 (PfExp2) is exclusively localized to the PVM. Two P. yoelii-exported proteins, PY04481 (encoded by a pyst-a gene) and PY06203 (PypAg-1), partially colocalized with these PyExp2-positive vesicles. Further analysis revealed that with P. yoelii, Plasmodium berghei, and P. falciparum, cytoplasmic Exp2-positive vesicles were primarily observed in CD71(+) reticulocytes versus mature RBCs. In transgenic P. yoelii 17X parasites, the association of hemagglutinin-tagged PyExp2 with the PVM and cytoplasmic vesicles was retained, but the pyexp2 gene was refractory to deletion. These data suggest that the localization of Exp2 in mouse and human RBCs can be influenced by the host cell environment. Exp2 may function at multiple points in the pathway by which parasites traffic proteins into and through the reticulocyte cytoplasm.
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11
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Abstract
Plasmodium falciparum, the causative agent of malaria, completely remodels the infected human erythrocyte to acquire nutrients and to evade the immune system. For this process, the parasite exports more than 10% of all its proteins into the host cell cytosol, including the major virulence factor PfEMP1 (P. falciparum erythrocyte surface protein 1). This unusual protein trafficking system involves long-known parasite-derived membranous structures in the host cell cytosol, called Maurer's clefts. However, the genesis, role, and function of Maurer's clefts remain elusive. Similarly unclear is how proteins are sorted and how they are transported to and from these structures. Recent years have seen a large increase of knowledge but, as yet, no functional model has been established. In this perspective we review the most important findings and conclude with potential possibilities to shed light into the enigma of Maurer's clefts. Understanding the mechanism and function of these structures, as well as their involvement in protein export in P. falciparum, might lead to innovative control strategies and might give us a handle with which to help to eliminate this deadly parasite.
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12
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van Ooij C, Withers-Martinez C, Ringel A, Cockcroft S, Haldar K, Blackman MJ. Identification of a Plasmodium falciparum phospholipid transfer protein. J Biol Chem 2013; 288:31971-83. [PMID: 24043620 PMCID: PMC3814793 DOI: 10.1074/jbc.m113.474189] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Infection of erythrocytes by the human malaria parasite Plasmodium falciparum results in dramatic modifications to the host cell, including changes to its antigenic and transport properties and the de novo formation of membranous compartments within the erythrocyte cytosol. These parasite-induced structures are implicated in the transport of nutrients, metabolic products, and parasite proteins, as well as in parasite virulence. However, very few of the parasite effector proteins that underlie remodeling of the host erythrocyte are functionally characterized. Using bioinformatic examination and modeling, we have found that the exported P. falciparum protein PFA0210c belongs to the START domain family, members of which mediate transfer of phospholipids, ceramide, or fatty acids between membranes. In vitro phospholipid transfer assays using recombinant PFA0210 confirmed that it can transfer phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine, and sphingomyelin between phospholipid vesicles. Furthermore, assays using HL60 cells containing radiolabeled phospholipids indicated that orthologs of PFA0210c can also transfer phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine. Biochemical and immunochemical analysis showed that PFA0210c associates with membranes in infected erythrocytes at mature stages of intracellular parasite growth. Localization studies in live parasites revealed that the protein is present in the parasitophorous vacuole during growth and is later recruited to organelles in the parasite. Together these data suggest that PFA0210c plays a role in the formation of the membranous structures and nutrient phospholipid transfer in the malaria-parasitized erythrocyte.
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Affiliation(s)
- Christiaan van Ooij
- From the Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
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13
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Remodeling of human red cells infected with Plasmodium falciparum and the impact of PHIST proteins. Blood Cells Mol Dis 2013; 51:195-202. [PMID: 23880461 DOI: 10.1016/j.bcmd.2013.06.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 06/08/2013] [Accepted: 06/10/2013] [Indexed: 01/27/2023]
Abstract
In an infected erythrocyte (iRBC), renovation and decoration are crucial for malarial parasite survival, pathogenesis and reproduction. Host cell remodeling is mediated by an array of diverse parasite-encoded export proteins that traffic within iRBC. These remodeling proteins extensively modify the membrane and cytoskeleton of iRBC and help in formation of parasite-induced novel organelles such as 'Maurer's Cleft (MC), tubulovesicular network (TVN) and parasitophorous vacuole membrane (PVM) inside the iRBC. The genome sequence of Plasmodium falciparum shows expansion of export proteins, which suggests a complex requirement of these export proteins for specific pathogenesis and erythrocyte remodeling. Plasmodium helical intersperse sub-telomeric (PHIST) is a family of seventy-two small export proteins and many of its recently discovered functional characteristics suggest an intriguing putative role in modification of an iRBC. This review highlights the recent advances in parasite genomics, proteomics, and cell biology studies unraveling the host cell modification; providing a speculation on the impact of PHIST proteins in modification of the iRBC.
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14
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Philipp S, Jakoby T, Tholey A, Janssen O, Leippe M, Gelhaus C. Cationic detergents enable the separation of membrane proteins of Plasmodium falciparum-infected erythrocytes by 2D gel electrophoresis. Electrophoresis 2012; 33:1120-8. [DOI: 10.1002/elps.201100520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Stephan Philipp
- Department of Zoophysiology; Zoological Institute; University of Kiel; Kiel; Germany
| | - Thomas Jakoby
- Division for Systematic Proteome Research,; Institute for Experimental Medicine; University of Kiel; Kiel; Germany
| | - Andreas Tholey
- Division for Systematic Proteome Research,; Institute for Experimental Medicine; University of Kiel; Kiel; Germany
| | - Ottmar Janssen
- Molecular Immunology,; Institute for Immunology; University of Kiel; Kiel; Germany
| | - Matthias Leippe
- Department of Zoophysiology; Zoological Institute; University of Kiel; Kiel; Germany
| | - Christoph Gelhaus
- Department of Zoophysiology; Zoological Institute; University of Kiel; Kiel; Germany
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15
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Lalle M, Currà C, Ciccarone F, Pace T, Cecchetti S, Fantozzi L, Ay B, Breton CB, Ponzi M. Dematin, a component of the erythrocyte membrane skeleton, is internalized by the malaria parasite and associates with Plasmodium 14-3-3. J Biol Chem 2010; 286:1227-36. [PMID: 21084299 DOI: 10.1074/jbc.m110.194613] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The malaria parasite invades the terminally differentiated erythrocytes, where it grows and multiplies surrounded by a parasitophorous vacuole. Plasmodium blood stages translocate newly synthesized proteins outside the parasitophorous vacuole and direct them to various erythrocyte compartments, including the cytoskeleton and the plasma membrane. Here, we show that the remodeling of the host cell directed by the parasite also includes the recruitment of dematin, an actin-binding protein of the erythrocyte membrane skeleton and its repositioning to the parasite. Internalized dematin was found associated with Plasmodium 14-3-3, which belongs to a family of conserved multitask molecules. We also show that, in vitro, the dematin-14-3-3 interaction is strictly dependent on phosphorylation of dematin at Ser(124) and Ser(333), belonging to two 14-3-3 putative binding motifs. This study is the first report showing that a component of the erythrocyte spectrin-based membrane skeleton is recruited by the malaria parasite following erythrocyte infection.
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Affiliation(s)
- Marco Lalle
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, 00161 Rome, Italy
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16
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Tilley L, Hanssen E. A 3D view of the host cell compartment in P. falciparum-infected erythrocytes. Transfus Clin Biol 2008; 15:72-81. [PMID: 18501653 DOI: 10.1016/j.tracli.2008.03.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Accepted: 03/27/2008] [Indexed: 10/22/2022]
Abstract
The most deadly of the human malaria parasites, Plasmodium falciparum, invades the erythrocytes of its host and initiates a remarkable series of morphological rearrangements within the host cell cytoplasm. The mature erythrocyte is effectively a floating sack of haemoglobin with no endogenous protein synthesis or protein trafficking machinery. In order to colonise and remodel its extracellular space, the parasite generates a series of novel structures that are involved in the export of virulence factors to the surface of the host cell. These include extensions of the parasite's vacuolar membrane, known as the tubulovesicular network, and structures referred to as Maurer's clefts. Maurer's clefts are convoluted collections of distorted discs that are tethered to the red blood cell membrane by structures with stalk-like profiles. Recently electron tomography has enabled visualisation--in three dimensions and at unprecedented resolution--the complexity of the membrane systems within the infected RBC cytoplasm.
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Affiliation(s)
- L Tilley
- Department of Biochemistry and Centre of Excellence for Coherent X-ray Science, La Trobe University, Melbourne, Victoria 3086, Australia.
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Spycher C, Rug M, Pachlatko E, Hanssen E, Ferguson D, Cowman AF, Tilley L, Beck HP. The Maurer's cleft protein MAHRP1 is essential for trafficking of PfEMP1 to the surface of Plasmodium falciparum-infected erythrocytes. Mol Microbiol 2008; 68:1300-14. [PMID: 18410498 DOI: 10.1111/j.1365-2958.2008.06235.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During the intra-erythrocytic development of Plasmodium falciparum, the parasite modifies the host cell surface by exporting proteins that interact with or insert into the erythrocyte membrane. These proteins include the principal mediator of cytoadherence, P. falciparum erythrocyte membrane protein 1 (PfEMP1). To implement these changes, the parasite establishes a protein-trafficking system beyond its confines. Membrane-bound structures called Maurer's clefts are intermediate trafficking compartments for proteins destined for the host cell membrane. We disrupted the gene for the membrane-associated histidine-rich protein 1 (MAHRP1). MAHRP1 is not essential for parasite viability or Maurer's cleft formation; however, in its absence, these organelles become disorganized in permeabilized cells. Maurer's cleft-resident proteins and transit cargo are exported normally in the absence of MAHRP1; however, the virulence determinant, PfEMP1, accumulates within the parasite, is depleted from the Maurer's clefts and is not presented at the red blood cell surface. Complementation of the mutant parasites with mahrp1 led to the reappearance of PfEMP1 on the infected red blood cell surface, and binding studies show that PfEMP1-mediated binding to CD36 is restored. These data suggest an important role of MAHRP1 in the translocation of PfEMP1 from the parasite to the host cell membrane.
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Affiliation(s)
- Cornelia Spycher
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, Socinstrasse 57, CH 4002 Basel, Switzerland
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18
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Tilley L, Sougrat R, Lithgow T, Hanssen E. The twists and turns of Maurer's cleft trafficking in P. falciparum-infected erythrocytes. Traffic 2007; 9:187-97. [PMID: 18088325 DOI: 10.1111/j.1600-0854.2007.00684.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The malaria parasite, Plasmodium falciparum, invades the red blood cells (RBCs) of its human host and initiates a series of morphological rearrangements within the host cell cytoplasm. The mature RBC has no endogenous trafficking machinery; therefore, the parasite generates novel structures to mediate protein transport. These include compartments called the Maurer's clefts (MC), which play an important role in the trafficking of parasite proteins to the surface of the host cell. Recent electron tomography studies have revealed MC as convoluted flotillas of flattened discs that are tethered to the RBC membrane, prompting speculation that the MC could, in one respect, represent an extracellular equivalent of the Golgi apparatus. Visualization of both resident and cargo proteins has helped decipher the signals and routes for trafficking of parasite proteins to the MC and beyond.
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Affiliation(s)
- Leann Tilley
- Department of Biochemistry, La Trobe University, Melbourne, Victoria 3086, Australia
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19
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Hanssen E, Sougrat R, Frankland S, Deed S, Klonis N, Lippincott-Schwartz J, Tilley L. Electron tomography of the Maurer's cleft organelles of Plasmodium falciparum-infected erythrocytes reveals novel structural features. Mol Microbiol 2007; 67:703-18. [PMID: 18067543 DOI: 10.1111/j.1365-2958.2007.06063.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
During intraerythrocytic development, the human malaria parasite, Plasmodium falciparum, establishes membrane-bound compartments, known as Maurer's clefts, outside the confines of its own plasma membrane. The Maurer's compartments are thought to be a crucial component of the machinery for protein sorting and trafficking; however, their ultrastructure is only partly defined. We have used electron tomography to image Maurer's clefts of 3D7 strain parasites. The compartments are revealed as flattened structures with a translucent lumen and a more electron-dense coat. They display a complex and convoluted morphology, and some regions are modified with surface nodules, each with a circular cross-section of approximately 25 nm. Individual 25 nm vesicle-like structures are also seen in the erythrocyte cytoplasm and associated with the red blood cell membrane. The Maurer's clefts are connected to the red blood cell membrane by regions with extended stalk-like profiles. Immunogold labelling with specific antibodies confirms differential labelling of the Maurer's clefts and the parasitophorous vacuole and erythrocyte membranes. Spot fluorescence photobleaching was used to demonstrate the absence of a lipid continuum between the Maurer's clefts and parasite membranes and the host plasma membrane.
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Affiliation(s)
- Eric Hanssen
- Department of Biochemistry and Centre of Excellence for Coherent X-ray Science, La Troube University, Melbourne, Victoria 3086, Australia
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20
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Spycher C, Rug M, Klonis N, Ferguson DJP, Cowman AF, Beck HP, Tilley L. Genesis of and trafficking to the Maurer's clefts of Plasmodium falciparum-infected erythrocytes. Mol Cell Biol 2006; 26:4074-85. [PMID: 16705161 PMCID: PMC1489082 DOI: 10.1128/mcb.00095-06] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 02/15/2006] [Accepted: 03/04/2006] [Indexed: 11/20/2022] Open
Abstract
Malaria parasites export proteins beyond their own plasma membrane to locations in the red blood cells in which they reside. Maurer's clefts are parasite-derived structures within the host cell cytoplasm that are thought to function as a sorting compartment between the parasite and the erythrocyte membrane. However, the genesis of this compartment and the signals directing proteins to the Maurer's clefts are not known. We have generated Plasmodium falciparum-infected erythrocytes expressing green fluorescent protein (GFP) chimeras of a Maurer's cleft resident protein, the membrane-associated histidine-rich protein 1 (MAHRP1). Chimeras of full-length MAHRP1 or fragments containing part of the N-terminal domain and the transmembrane domain are successfully delivered to Maurer's clefts. Other fragments remain trapped within the parasite. Fluorescence photobleaching and time-lapse imaging techniques indicate that MAHRP1-GFP is initially trafficked to isolated subdomains in the parasitophorous vacuole membrane that appear to represent nascent Maurer's clefts. The data suggest that the Maurer's clefts bud from the parasitophorous vacuole membrane and diffuse within the erythrocyte cytoplasm before taking up residence at the cell periphery.
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Affiliation(s)
- Cornelia Spycher
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, Socinstrasse 57, CH 4002 Basel, Switzerland
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21
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Bracho C, Dunia I, Romano M, Raposo G, De La Rosa M, Benedetti EL, Pérez HA. Caveolins and flotillin-2 are present in the blood stages of Plasmodium vivax. Parasitol Res 2006; 99:153-9. [PMID: 16521037 DOI: 10.1007/s00436-006-0139-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 01/30/2006] [Indexed: 02/01/2023]
Abstract
Blood stages of Plasmodium vivax induce the development of caveolae and caveola-vesicle complexes (CVC) in the membrane of their host erythrocyte. Caveolae are found in almost all types of cells and are involved in endogenous processes as calcium and cholesterol homeostasis, cell signalling, transporting, ligand internalization and transcytosis of serum components. Major structural components of caveolae are the proteins caveolins and flotillins. The functional role of caveolae in the P. vivax-infected erythrocyte is not properly understood. As these organelles have been shown to contain malaria antigens, it has been suggested that they are involved in the transport and release of specific parasite antigens from the infected erythrocyte and in the uptake of plasma proteins. Using specific antibodies to classical caveolae proteins and an immunolocalization approach, we found caveolin-2, caveolin-3, and flotillin-2 in the vesicle profiles and some CVC of P. vivax-infected erythrocytes. Caveolin-1-3 were not found in uninfected erythrocytes. This is the first report of identification and localization of caveolins in the CVC present in erythrocytes infected with P. vivax, thereby providing evidence of the role of this particular organelle in the protein-trafficking pathway that connect parasite-encoded proteins with the erythrocyte cytoplasm and the cell surface throughout the asexual blood cycle of vivax malaria parasite.
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Affiliation(s)
- Carmen Bracho
- Instituto Venezolano de Investigaciones Científicas (IVIC), Centro de Microbiología y Biología Celular, Apdo. 21827, Caracas 1020A, Venezuela.
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22
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Lanzer M, Wickert H, Krohne G, Vincensini L, Braun Breton C. Maurer's clefts: A novel multi-functional organelle in the cytoplasm of Plasmodium falciparum-infected erythrocytes. Int J Parasitol 2006; 36:23-36. [PMID: 16337634 DOI: 10.1016/j.ijpara.2005.10.001] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Revised: 09/23/2005] [Accepted: 10/04/2005] [Indexed: 10/25/2022]
Abstract
Discovered in 1902 by Georg Maurer as a peculiar dotted staining pattern observable by light microscopy in the cytoplasm of erythrocytes infected with the human malarial parasite Plasmodium falciparum, the function of Maurer's clefts have remained obscure for more than a century. The growing interest in protein sorting and trafficking processes in malarial parasites has recently aroused the Maurer's clefts from their deep slumber. Mounting evidence suggests that Maurer's clefts are a secretory organelle, which the parasite establishes within its host erythrocyte, but outside its own confines, to route parasite proteins across the host cell cytoplasm to the erythrocyte surface where they play a role in nutrient uptake and immune evasion processes. Moreover, Maurer's clefts seem to play a role in cell signaling, merozoite egress, phospholipid biosynthesis and, possibly, other biochemical pathways. Here, we review our current knowledge of the ultrastructure of Maurer's clefts, their proteinaceous composition and their function in protein trafficking.
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Affiliation(s)
- Michael Lanzer
- Abteilung Parasitologie, Hygiene-Institut, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany.
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23
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Wickert H, Göttler W, Krohne G, Lanzer M. Maurer's cleft organization in the cytoplasm of plasmodium falciparum-infected erythrocytes: new insights from three-dimensional reconstruction of serial ultrathin sections. Eur J Cell Biol 2005; 83:567-82. [PMID: 15679102 DOI: 10.1078/0171-9335-00432] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Maurer's clefts are single-membrane-limited structures in the cytoplasm of erythrocytes infected with the human malarial parasite Plasmodium falciparum. The currently accepted model suggests that Maurer's clefts act as an intermediate compartment in protein transport processes from the parasite across the cytoplasm of the host cell to the erythrocyte surface, by receiving and delivering protein cargo packed in vesicles. This model is mainly based on two observations. Firstly, single-section electron micrographs have shown, within the cytoplasm of infected erythrocytes, stacks of long slender membranes in close vicinity to round membrane profiles considered to be vesicles. Secondly, proteins that are transported from the parasite to the erythrocyte surface as well as proteins facilitating the budding of vesicles have been found in association with Maurer's clefts. Verification of this model would be greatly assisted by a better understanding of the morphology, dimensions and origin of the Maurer's clefts. Here, we have generated and analyzed three-dimensional reconstructions of serial ultrathin sections covering segments of P. falciparum-infected erythrocytes of more than 1 microm thickness. Our results indicate that Maurer's clefts are heterogeneous in structure and size. We have found Maurer's clefts consisting of a single disk-shaped cisternae localized beneath the plasma membrane. In other examples, Maurer' clefts formed an extended membranous network that bridged most of the distance between the parasite and the plasma membrane of the host erythrocyte. Maurer's cleft membrane networks were composed of both branched membrane tubules and stacked disk-shaped membrane cisternae that eventually formed whorls. Maurer's clefts were visible in other cells as a loose membrane reticulum composed of scattered tubular and disk-shaped membrane profiles. We have not seen clearly discernable isolated vesicles in the analyzed erythrocyte segments suggesting that the current view of how proteins are transported within the Plasmodium-infected erythrocyte may need reconsideration.
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Affiliation(s)
- Hannes Wickert
- Division of Electron Microscopy Biocenter, University of Würzburg, Germany
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24
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Cooke BM, Lingelbach K, Bannister LH, Tilley L. Protein trafficking in Plasmodium falciparum-infected red blood cells. Trends Parasitol 2004; 20:581-9. [PMID: 15522668 DOI: 10.1016/j.pt.2004.09.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Plasmodium falciparum inhabits a niche within the most highly terminally differentiated cell in the human body--the mature red blood cell. Life inside this normally quiescent cell offers the parasite protection from the host's immune system, but provides little in the way of cellular infrastructure. To survive and replicate in the red blood cell, the parasite exports proteins that interact with and dramatically modify the properties of the host red blood cell. As part of this process, the parasite appears to establish a system within the red blood cell cytosol that allows the correct trafficking of parasite proteins to their final cellular destinations. In this review, we examine recent developments in our understanding of the pathways and components involved in the delivery of important parasite-encoded proteins to their final destination in the host red blood cell. These complex processes are not only fundamental to the survival of malaria parasites in vivo, but are also major determinants of the unique pathogenicity of this parasite.
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Affiliation(s)
- Brian M Cooke
- Department of Microbiology, Monash University, Victoria 3800, Australia.
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25
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Przyborski JM, Lanzer M. Protein transport and trafficking inPlasmodium falciparum-infected erythrocytes. Parasitology 2004; 130:373-88. [PMID: 15830811 DOI: 10.1017/s0031182004006729] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The human malarial parasitePlasmodium falciparumextensively modifies its host erythrocyte, and to this end, is faced with an interesting challenge. It must not only sort proteins to common organelles such as endoplasmic reticulum, Golgi and mitochondria, but also target proteins across the ‘extracellular’ cytosol of its host cell. Furthermore, as a member of the phylum Apicomplexa, the parasite has to sort proteins to novel organelles such as the apicoplast, micronemes and rhoptries. In order to overcome these difficulties, the parasite has created a novel secretory system, which has been characterized in ever-increasing detail in the past decade. Along with the ‘hardware’ for a secretory system, the parasite also needs to ‘program’ proteins to enable high fidelity sorting to their correct subcellular location. The nature of these sorting signals has remained until relatively recently, enigmatic. Experimental work has now begun to dissect the sorting signals responsible for correct subcellular targeting of parasite-encoded proteins. In this review we summarize the current understanding of such signals, and comment on their role in protein sorting in this organism, which may become a model for the study of novel protein trafficking mechanisms.
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Affiliation(s)
- J M Przyborski
- Hygiene Institute, Department of Parasitology, University of Heidelberg, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany
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26
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Rug M, Wickham ME, Foley M, Cowman AF, Tilley L. Correct promoter control is needed for trafficking of the ring-infected erythrocyte surface antigen to the host cytosol in transfected malaria parasites. Infect Immun 2004; 72:6095-105. [PMID: 15385514 PMCID: PMC517558 DOI: 10.1128/iai.72.10.6095-6105.2004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2004] [Revised: 05/22/2004] [Accepted: 06/15/2004] [Indexed: 11/20/2022] Open
Abstract
Following invasion of human erythrocytes, the malaria parasite, Plasmodium falciparum, exports proteins beyond the confines of its own plasma membrane to modify the properties of the host red cell membrane. These modifications are critical to the pathogenesis of malaria. Analysis of the P. falciparum genome sequence has identified a large number of molecules with putative atypical signal sequences. The signals remain poorly characterized; however, a number of molecules with these motifs localize to the host erythrocyte. To examine the role of these atypical signal sequences in the export of parasite proteins, we have generated transfected parasites expressing a chimeric protein comprising the N-terminal region of the P. falciparum ring-infected erythrocyte surface antigen (RESA) appended to green fluorescent protein (GFP). This N-terminal region contains a hydrophobic stretch of amino acids that is presumed to act as a noncanonical secretory signal sequence. Modulation of the timing of transgene expression demonstrates that trafficking of malaria proteins into the host erythrocyte is dependent on both the presence of an appropriate transport signal and the timing of expression. Transgene expression under the control of a trophozoite-specific promoter mistargets the chimeric molecule to the parasitophorous vacuole surrounding the parasite. However, expression of RESA-GFP in schizont stages, under the control of the RESA promoter, enables correct trafficking of a population of the chimeric protein to the host erythrocyte.
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Affiliation(s)
- Melanie Rug
- Department of Biochemistry, La Trobe University, Melbourne, Victoria, Australia
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27
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Abstract
During intra-erythrocytic development, the human malarial parasite Plasmodium falciparum extensively remodels its adopted cellular home by exporting proteins beyond the confines of its own plasma membrane, but is, however, faced with a major problem: the lack of an endogenous protein trafficking machinery within the host erythrocyte. Thus, in order to export proteins the parasite has to install its own protein export system within the host erythrocyte. A growing body of evidence suggests that Maurer's clefts, parasite-derived membranous structures in the cytosol of the host cell, are a crucial component of this protein sorting and trafficking machinery. In this review we summarize our current understanding of the ultra-structure of Maurer's clefts and their role in protein transport process.
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Affiliation(s)
- Jude M Przyborski
- Department of Parasitology, Hygiene Institute, University of Heidelberg, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany
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28
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Spielmann T, Fergusen DJP, Beck HP. etramps, a new Plasmodium falciparum gene family coding for developmentally regulated and highly charged membrane proteins located at the parasite-host cell interface. Mol Biol Cell 2003; 14:1529-44. [PMID: 12686607 PMCID: PMC153120 DOI: 10.1091/mbc.e02-04-0240] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
After invasion of erythrocytes, the human malaria parasite Plasmodium falciparum resides within a parasitophorous vacuole and develops from morphologically and metabolically distinct ring to trophozoite stages. During these developmental phases, major structural changes occur within the erythrocyte, but neither the molecular events governing this development nor the molecular composition of the parasitophorous vacuole membrane (PVM) is well known. Herein, we describe a new family of highly cationic proteins from P. falciparum termed early transcribed membrane proteins (ETRAMPs). Thirteen members were identified sharing a conserved structure, of which six were found only during ring stages as judged from Northern and Western analysis. Other members showed different stage-specific expression patterns. Furthermore, ETRAMPs were associated with the membrane fractions in Western blots, and colocalization and selective permeabilization studies demonstrated that ETRAMPs were located in the PVM. This was confirmed by immunoelectron microscopy where the PVM and tubovesicular extensions of the PVM were labeled. Early expressed ETRAMPs clearly defined separate PVM domains compared with the negatively charged integral PVM protein EXP-1, suggesting functionally different domains in the PVM with an oppositely charged surface coat. We also show that the dynamic change of ETRAMP composition in the PVM coincides with the morphological changes during development. The P. falciparum PVM is an important structure for parasite survival, and its analysis might provide better understanding of the requirements of intracellular parasites.
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Affiliation(s)
- Tobias Spielmann
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, Basel CH 4002, Switzerland
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29
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Adisa A, Rug M, Klonis N, Foley M, Cowman AF, Tilley L. The signal sequence of exported protein-1 directs the green fluorescent protein to the parasitophorous vacuole of transfected malaria parasites. J Biol Chem 2003; 278:6532-42. [PMID: 12456681 DOI: 10.1074/jbc.m207039200] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The malaria parasite, Plasmodium falciparum, spends part of its life cycle inside the erythrocytes of its human host. In the mature stages of intraerythrocytic growth, the parasite undertakes extensive remodeling of its adopted cellular home by exporting proteins beyond the confines of its own plasma membrane. To examine the signals involved in export of parasite proteins, we have prepared transfected parasites expressing a chimeric protein comprising the N-terminal region of the Plasmodium falciparum exported protein-1 appended to green fluorescent protein. The majority of the population of the chimeric protein appears to be correctly processed and trafficked to the parasitophorous vacuole, indicating that this is the default destination for protein secretion. Some of the protein is redirected to the parasite food vacuole and further degraded. Photobleaching studies reveal that the parasitophorous vacuole contains subcompartments that are only partially interconnected. Dual labeling with the lipid probe, BODIPY-TR-ceramide, reveals the presence of membrane-bound extensions that can bleb from the parasitophorous vacuole to produce double membrane-bound compartments. We also observed regions and extensions of the parasitophorous vacuole, where there is segregation of the lumenal chimera from the lipid components. These regions may represent sites for the sorting of proteins destined for the trafficking to sites beyond the parasitophorous vacuole membrane.
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Affiliation(s)
- Akinola Adisa
- Department of Biochemistry, La Trobe University, Bundoora, 3086, Victoria, Australia
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30
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Eksi S, Stump A, Fanning SL, Shenouda MI, Fujioka H, Williamson KC. Targeting and sequestration of truncated Pfs230 in an intraerythrocytic compartment during Plasmodium falciparum gametocytogenesis. Mol Microbiol 2002; 44:1507-16. [PMID: 12067340 DOI: 10.1046/j.1365-2958.2002.02986.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
For malaria to be transmitted, the Plasmodium falciparum parasite must invade an erythrocyte and undergo gametocytogenesis. When mature intraerythrocytic gametocytes are taken up in a blood meal by a mosquito they emerge as gametes and, once fertilized, continue to differentiate into infectious sporozoites. One of the major proteins associated with the surface of the parasite during gamete differentiation is Pfs230, a 360 kDa member of a family of P. falciparum proteins that contains a repeated cysteine motif domain. To characterize the role of different regions of Pfs230, the gene was disrupted by targeted integration and clones isolated that expressed distinct sections of Pfs230. Independent clones D1.356 a and b express the first 452 amino acids (aa) of Pfs230 and do not contain a cysteine motif domain, whereas clones D2.850 a and b express the first 950 aa, including the first cysteine motif domain. Although both sets of clones undergo gametogenesis and produce morphologically normal gametes, neither truncated Pfs230 is located on the surface of the gamete. In clones D1.356 a and b, the 452 aa Pfs230 is secreted into the parasitophorous vacuole and released as a soluble protein when the parasite emerges from the erythrocyte as a gamete. In marked contrast, the 950 aa form of Pfs230 expressed by clones D2.850 a and b is sequestered in a novel tubular compartment in the erythrocyte cytoplasm. This sexual-stage tubular intraerythrocytic compartment (STIC) is not recognized by antibodies specific for proteins associated with the parasitophorous vacuole membrane (Pfs16 or Exp-1) or Maurer's clefts (Pfsbp 1 or mAb LWL1) or intraerythrocytic asexual parasite proteins (PfEMP2 or HRP II).
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Affiliation(s)
- Saliha Eksi
- Department of Biology, Loyola University Chicago, Chicago, IL 60626, USA
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31
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Albano FR, Foley M, Tilley L. Export of parasite proteins to the erythrocyte cytoplasm: secretory machinery and traffic signals. NOVARTIS FOUNDATION SYMPOSIUM 2000; 226:157-72; discussion 173-5. [PMID: 10645545 DOI: 10.1002/9780470515730.ch12] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
To the malaria parasite, the prospect of setting up residence within a human erythrocyte represents a formidable challenge. The mature human erythrocyte is essentially a bag of haemoglobin with no internal organelles and no protein synthesis machinery. The parasite needs, therefore, to assemble all the essential amenities--foundations, plumbing and furnishings--from scratch. The parasite remodels its adopted home by exporting proteins to the erythrocyte membrane. To reach their final destinations, the exported proteins must cross the parasite plasma membrane, the parasitophorous vacuole membrane and the erythrocyte cytosol. To further understand this unusual and complex trafficking pathway, we have searched for proteins that may form part of the trafficking machinery of the infected erythrocyte. We have identified an ER-located, calcium-binding homologue of reticulocalbin (PfERC) that co-localizes with the ER molecular chaperone, PfGRP. We have also identified a homologue of the GTP-binding protein, Sar1p, a small GTPase that, in other eukaryotic cells, is thought to play a crucial role in trafficking proteins between the ER and the Golgi. PfSar1p is located in discrete structures near the periphery of the parasite cytoplasm that may represent specialized export compartments. PfSar1p is exported to structures outside the parasite in the erythrocyte cytoplasm. The malaria parasite appears to be capable of elaborating components of the 'classical' vesicle mediated trafficking machinery outside the boundaries of its own plasma membrane.
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Affiliation(s)
- F R Albano
- Department of Biochemistry, La Trobe University, Bundoora, Australia
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32
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Bozdech Z, Schurr E. Protein transport in the host cell cytoplasm and ATP-binding cassette proteins in Plasmodium falciparum-infected erythrocytes. NOVARTIS FOUNDATION SYMPOSIUM 2000; 226:231-41; discussion 241-5. [PMID: 10645549 DOI: 10.1002/9780470515730.ch16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The main interest of our experiments is the study of ATP-binding cassette (ABC) proteins in Plasmodium parasites and their infected host cells. Here, we report on results obtained by studying the plasmodial PfGCN20 ABC protein. Employing immunomicroscopy and cell fractionation techniques, we found that PfGCN20 is localized to multiple regions of the infected erythrocyte, including membranous and non-membranous compartments inside and outside of the parasite cell. PfGCN20 was found to complement the function of its yeast homologue Gcn20p by acting as part of the yeast translation regulatory pathway. These results open up several hypotheses about a possible biological function of PfGCN20, such as being a component of plasmodial translation regulation, or functioning as an ATP-binding subunit of a multimeric ABC transporter, or acting as a molecular chaperone-like enzyme contributing to the protein translocation across multiple membranes in infected erythrocytes. More experiments are presently being performed to fully understand the biological function of this protein, abundant in multiple compartments of erythrocytes infected with the Plasmodium falciparum malaria parasite.
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Affiliation(s)
- Z Bozdech
- McGill Centre for the Study of Host Resistance, Department of Experimental Medicine, McGill University, Montreal, Quebec, Canada
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33
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Albano FR, Berman A, La Greca N, Hibbs AR, Wickham M, Foley M, Tilley L. A homologue of Sar1p localises to a novel trafficking pathway in malaria-infected erythrocytes. Eur J Cell Biol 1999; 78:453-62. [PMID: 10472798 DOI: 10.1016/s0171-9335(99)80072-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We have identified a homologue of the GTP-binding protein, Sar1p, in Plasmodium falciparum. Sar1p is a small GTPase that is thought to play a crucial role in trafficking of proteins between the endoplasmic reticulum and the Golgi. The P.falciparum SAR1 gene is located on chromosome 4 and comprises two exons separated by a 508 bp intron. The deduced amino acid sequence of PfSar1p (GenBank accession number AF104306) shows 71% similarity (58% identity) to Sar1p from Saccharomyces cerevisiae. Expression of PfSar1p in erythrocytic stages of P. falciparum was confirmed by sequencing of a tryptic peptide derived from a polypeptide excised from an SDS-polyacrylamide gel. A recombinant protein corresponding to approximately 70% of the PfSar1p sequence was used to raise antibodies. The affinity-purified antiserum recognised a protein with an apparent molecular weight of 23 K in Western blots of malaria-infected erythrocytes but not in uninfected erythrocytes. PfSar1p was shown to be largely insoluble in non-ionic detergent and a low ionic strength buffer. Confocal immunofluorescence microscopy of malaria-infected erythrocytes was used to show that PfSar1p is located near the periphery of the parasite in discrete compartments, which appear to be distinct from the parasite endoplasmic reticulum. In addition, PfSar1p appears to be exported to structures outside the parasite in the erythrocyte cytoplasm. The export of PfSar1p to the erythrocyte cytosol is inhibited by treatment with brefeldin A. This provides the first evidence that the malaria parasite is capable of elaborating components of the classical vesicle-mediated trafficking machinery outside the boundaries of its own plasma membrane.
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Affiliation(s)
- F R Albano
- Department of Biochemistry, La Trobe University, Melbourne, Australia
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34
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Akompong T, VanWye J, Ghori N, Haldar K. Artemisinin and its derivatives are transported by a vacuolar-network of Plasmodium falciparum and their anti-malarial activities are additive with toxic sphingolipid analogues that block the network. Mol Biochem Parasitol 1999; 101:71-9. [PMID: 10413044 DOI: 10.1016/s0166-6851(99)00056-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
There is great need to identify and characterize drug targets and chemotherapeutic strategies against malaria. Here we show that a vacuolar-network induced by the human malaria parasite Plasmodium falciparum, is a major import pathway for artemisinin, a leading, new anti-malarial that is known to be effective against drug resistant strains. We also show that artemisinin-treatment induces aberrant, budding of a vacuolar-network membrane protein and its antimalarial activity is additive with toxic sphingolipid analogues that block the network. The data suggest that artemisinin alters membrane protein export from the vacuolar-network and combinations with anti-network reagents have the potential to provide powerful new chemotherapy for drug resistant malaria.
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Affiliation(s)
- T Akompong
- Department of Microbiology and Immunology, Stanford University School of Medicine, CA 94305-5402, USA
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35
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Furtado GC, Moura IC, Pudles J, Alvarez JM, D'Império Lima MR. Plasmodium chabaudi chabaudi: a monoclonal antibody raised against soluble antigens present in the plasma of infected mice recognizes a 250-kDa schizont glycoprotein that is secreted during schizogony. Exp Parasitol 1999; 91:97-100. [PMID: 9920048 DOI: 10.1006/expr.1999.4329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- G C Furtado
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, SP, Brasil
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36
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Bozdech Z, VanWye J, Haldar K, Schurr E. The human malaria parasite Plasmodium falciparum exports the ATP-binding cassette protein PFGCN20 to membrane structures in the host red blood cell. Mol Biochem Parasitol 1998; 97:81-95. [PMID: 9879889 DOI: 10.1016/s0166-6851(98)00135-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PFGCN20 is a member of the ATP-binding cassette family of proteins that is closely related to the yeast translational regulator Gcn20p. We have generated a polyclonal antibody against the N-terminal region of PFGCN20 and studied the cellular localization of PFGCN20 throughout the erythrocytic life cycle of Plasmodium falciparum. PFGCN20 was found to be present at all stages and a pronounced export of PFGCN20 into the erythrocyte was observed in the trophozoite and schizont stages. In the indirect immunofluorescence assay, PFGCN20 was found to display significant colocalization with antigens detected by the monoclonal antibody 41E11. In contrast, there was only a minimal overlap of PFGCN20 localization with EMP2 and HRP2. Immunoelectron microscopy demonstrated a pronounced accumulation of PFGCN20 in the lumen of the parasitophorous vacuole and deconvolution fluorescence microscopy showed membrane association with selective regions of a tubovesicular network in the red cell. We also observed a concentration of PFGCN20 in electron-dense plaques just underneath the parasite's plasma membrane and an association of PFGCN20 with cytoplasmic vesicular structures within the parasite. The observed export of PFGCN20 and its association with the tubovesicular network in host red cells, may be indicative of the fact that PFGCN20 functions as ATP-binding subunit of an unknown multimeric ABC-transporter. The cytoplasmic localization of PFGCN20 in the parasite, however, suggests that the involvement of PFGCN20 in translational regulation or other cytoplasmic biological functions cannot be ruled out.
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Affiliation(s)
- Z Bozdech
- McGill Centre for the Study of Host Resistance, Department of Experimental Medicine, McGill University, Montreal, Quebec, Canada
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37
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Abstract
The malaria parasite invades the human erythrocyte and converts this simple "sack of haemoglobin" back into a functional eukaryotic cell. Parasite-encoded proteins are trafficked to the red blood cell membrane where they modify its properties to meet the needs of the intracellular parasite. Trafficking of proteins within the parasite probably occurs via a "classical" vesicle-mediated secretory pathway; however, the transit of proteins from the parasite plasma membrane to the erythrocyte membrane appears to involve both a novel vesicle-mediated pathway and a direct protein-translocation system. The polypeptide signals that direct parasite proteins into these novel export pathways may include an unusual "internal" hydrophobic sequence, as well as a series of basic motifs.
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Affiliation(s)
- M Foley
- Department of Biochemistry, La Trobe University, Bundoora, Victoria, Australia
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38
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Fischer HG, Stachelhaus S, Sahm M, Meyer HE, Reichmann G. GRA7, an excretory 29 kDa Toxoplasma gondii dense granule antigen released by infected host cells. Mol Biochem Parasitol 1998; 91:251-62. [PMID: 9566518 DOI: 10.1016/s0166-6851(97)00227-2] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Monoclonal antibody (mAb) TxE2, reactive with Toxoplasma gondii excretory products, detects an acidic 29 kDa protein (p29) which, in 2D gel electrophoresis, exhibits a migration pattern distinct from those of the toxoplasmic excretory proteins described so far. The sequence of seven peptides from tryptic digestion of isolated p29 allowed the design of primers to obtain the coding DNA sequence. The full-length gene was amplified from genomic DNA of T. gondii strain BK and the sequence was identical with that of the corresponding cDNA, providing evidence for an intron-free gene structure. A single mRNA transcript of 1.3 kb was detected by Northern blot analysis. The deduced 236 amino acid protein contains a putative N-terminal signal peptide, one site of potential N-linked glycosylation, and, close to the C-terminus, a further hydrophobic, putative transmembrane domain. With synthetic peptides spanning the sequence of p29, the epitope for mAb TxE2 was mapped adjacent to the putative signal sequence. The antigen, which represents almost 0.5% of T. gondii protein, is expressed in strains of all three intraspecies subgroups, and is associated with the parasite dense granules as demonstrated by immunoelectron microscopy. In tachyzoite-infected cells, p29 accumulates within the parasitophorous vacuole and co-localizes with its delimiting membrane. In bradyzoite-infected cells, p29 is present within the host cell cytoplasm as detected by immunofluorescence staining, and, furthermore, in the supernatant of cyst-bearing cell culture lacking extracellular parasites as shown by enzyme-linked immunosorbent assay (ELISA). Thus, p29 which is named dense granule protein (GRA)7 may indicate the presence of intracellular toxoplasma.
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Affiliation(s)
- H G Fischer
- Institute for Medical Microbiology and Virology, Heinrich-Heine-Universität, Düsseldorf, Germany.
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39
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Martinez SL, Clavijo CA, Winograd E. Identification of peripheral membrane proteins associated with the tubo-vesicular network of Plasmodium falciparum infected erythrocytes. Mol Biochem Parasitol 1998; 91:273-80. [PMID: 9566520 DOI: 10.1016/s0166-6851(97)00206-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
During intracellular development of the malarial parasite numerous membranous vesicles appear in the infected erythrocyte cytoplasm between the parasitophorous vacuolar membrane (PVM) and the erythrocyte plasma membrane. In this study we describe the characterization of a monoclonal antibody which recognizes two major parasite-encoded proteins of 50 and 41 kDa. Immunofluorescence and immunoelectron microscopy demonstrated that the monoclonal antibody reacts with cytoplasmic vesicles of Plasmodium falciparum infected erythrocyte referred to as Maurer's clefts. The antigens recognized by the monoclonal antibody were expressed very early during the erythrocytic life cycle of the parasite, and remained tightly associated within membrane vesicles even after merozoites are released from infected erythrocytes. The antigens were partially soluble in non-ionic detergents, and were released from the membrane by alkali treatment, indicating that the proteins recognized by the monoclonal antibody are peripheral membrane proteins. It is proposed that the 50 and 41 kDa antigens might be part of an underlying membrane skeletal network that provides structural support to vesicles and tubules present in the infected erythrocyte cytoplasm.
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Affiliation(s)
- S L Martinez
- Laboratorio de Biología Celular, Instituto Nacional de Salud, Bogotá, Colombia
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40
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Shahabuddin M, Gayle M, Zieler H, Laughinghouse A. Plasmodium gallinaceum: fluorescent staining of zygotes and ookinetes to study malaria parasites in mosquito. Exp Parasitol 1998; 88:79-84. [PMID: 9538861 DOI: 10.1006/expr.1998.4198] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have developed a fluorescent labeling procedure for staining the mosquito stages of Plasmodium gallinaceum. PKH26, a lipophilic dye, is efficiently and permanently incorporated into the membranes of zygotes and ookinetes. Stained zygotes undergo normal development into ookinetes; the stain does not interfere with ookinete mobility or ability to adhere to the mosquito midgut lumen. Stained zygotes and ookinetes are comparable to untreated parasites in their ability to give rise to oocysts when fed to mosquitoes. This technique can be used to study the development of Plasmodium parasites in the complex cellular environment of the mosquito midgut after a blood meal. It may also be adapted to study other parasite-vector interactions.
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Affiliation(s)
- M Shahabuddin
- Medical Entomology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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41
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Trager W, Jensen JB. Continuous culture of Plasmodium falciparum: its impact on malaria research. Int J Parasitol 1997; 27:989-1006. [PMID: 9363481 DOI: 10.1016/s0020-7519(97)00080-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The methods developed by us in 1976 for the continuous culture of the erythrocytic stages of Plasmodium falciparum make this organism available to a large variety of scientists. As a result, much has been learned about P. falciparum during the past 20 years. Here we attempt to emphasize recent developments in the diverse aspects for which the culture method has been particularly useful: chemotherapy; drug resistance; vaccine development; pathogenesis; export of proteins into the host cell; cell biology, the mitochondrion and the plastid; innate resistance involving mutant human erythrocytes; gametocytogenesis; genetics, transfection; molecular biology; biochemistry; extracellular cultivation.
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Affiliation(s)
- W Trager
- Rockefeller University, New York, NY 10021, USA
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42
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Olliaro P, Castelli F. Plasmodium falciparum: an electronmicroscopy study of caveolae and trafficking between the parasite and the extracellular medium. Int J Parasitol 1997; 27:1007-12. [PMID: 9363482 DOI: 10.1016/s0020-7519(97)00083-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Caveolae containing grape-like tubulovesicular structures were observed in the cytoplasm and in the parasitophorous vacuole of ring- and trophozoite-stage Plasmodium falciparum parasites. In appliqué-forms intact caveolae and free vesicles were also seen to bud off the surface of infected erythrocytes directly from the parasitophorous vacuole where the parasite was in close vicinity to the host cell membrane. The mean vesicle diameter was 0.08-0.1 micron. No such structure was observed in schizonts, segmenters or in the cytoplasm of infected or uninfected erythrocytes. These structures may represent morphological evidence in P. falciparum of a "window" through which the parasite would have direct access to the extracellular milieu. They may constitute carrier vesicles containing parasite membrane transport molecules possibly involved in malaria pathogenesis and/or immunity.
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Affiliation(s)
- P Olliaro
- UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, Geneva, Switzerland.
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43
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Deitsch KW, Wellems TE. Membrane modifications in erythrocytes parasitized by Plasmodium falciparum. Mol Biochem Parasitol 1996; 76:1-10. [PMID: 8919990 DOI: 10.1016/0166-6851(95)02575-8] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Plasmodium falciparum malaria parasites invade human red blood cells and immediately begin making significant alterations to the structure of the erythrocyte. These alterations facilitate the movement of nutrients into, and waste products and parasite-derived proteins out of the cell to meet the needs of the growing parasite. A tubovesicular membrane network extending from the parasite vacuole membrane probably has a central role in the transport processes. The parasite also modifies the erythrocyte membrane itself in a way that not only changes its permeability but also places parasite-derived proteins in knob-like protrusions at the cell surface. These proteins enable the parasite to adhere to endothelial cells and thereby avoid clearance from the blood stream by the spleen. Antigenic variation of these proteins allows parasitized erythrocytes to vary their phenotype and produce a sustained and chronic malaria infection. Study of the molecular processes that underlie these parasite-induced modifications of the host red blood cell will lead to improved understanding of malaria pathogenesis and, perhaps, suggest new approaches against the disease.
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Affiliation(s)
- K W Deitsch
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0425, USA
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44
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Abstract
In real-estate agent's terms, the red blood cell is a renovator's dream. The mature human erythrocyte has no internal organelles, no protein synthesis machinery and no infrastructure for protein trafficking. The malaria parasite invades this empty shell and effectively converts the erythrocyte back into a fully functional eukaryotic cell. In this article, Michael Foley and Leann Tilley examine the Plasmodium falciparum proteins that interact with the membrane skeleton at different stages of the infection and speculate on the roles of these proteins in the remodelling process.
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Affiliation(s)
- M Foley
- School of Biochemistry, La Trobe University, Bundoora, Victoria, Australia.
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45
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Elford BC, Cowan GM, Ferguson DJ. Parasite-regulated membrane transport processes and metabolic control in malaria-infected erythrocytes. Biochem J 1995; 308 ( Pt 2):361-74. [PMID: 7772015 PMCID: PMC1136935 DOI: 10.1042/bj3080361] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- B C Elford
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, U.K
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