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Malaria Parasite Proteins and Their Role in Alteration of the Structure and Function of Red Blood Cells. ADVANCES IN PARASITOLOGY 2015; 91:1-86. [PMID: 27015947 DOI: 10.1016/bs.apar.2015.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Malaria, caused by Plasmodium spp., continues to be a major threat to human health and a significant cause of socioeconomic hardship in many countries. Almost half of the world's population live in malaria-endemic regions and many of them suffer one or more, often life-threatening episodes of malaria every year, the symptoms of which are attributable to replication of the parasite within red blood cells (RBCs). In the case of Plasmodium falciparum, the species responsible for most malaria-related deaths, parasite replication within RBCs is accompanied by striking alterations to the morphological, biochemical and biophysical properties of the host cell that are essential for the parasites' survival. To achieve this, the parasite establishes a unique and extensive protein export network in the infected RBC, dedicating at least 6% of its genome to the process. Understanding the full gamut of proteins involved in this process and the mechanisms by which P. falciparum alters the structure and function of RBCs is important both for a more complete understanding of the pathogenesis of malaria and for development of new therapeutic strategies to prevent or treat this devastating disease. This review focuses on what is currently known about exported parasite proteins, their interactions with the RBC and their likely pathophysiological consequences.
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202
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Budu A, Gomes MM, Melo PM, El Chamy Maluf S, Bagnaresi P, Azevedo MF, Carmona AK, Gazarini ML. Calmidazolium evokes high calcium fluctuations in Plasmodium falciparum. Cell Signal 2015; 28:125-135. [PMID: 26689736 DOI: 10.1016/j.cellsig.2015.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 11/30/2015] [Accepted: 12/07/2015] [Indexed: 10/22/2022]
Abstract
Calcium and calmodulin (CaM) are important players in eukaryote cell signaling. In the present study, by using a knockin approach, we demonstrated the expression and localization of CaM in all erythrocytic stages of Plasmodium falciparum. Under extracellular Ca(2+)-free conditions, calmidazolium (CZ), a potent CaM inhibitor, promoted a transient cytosolic calcium ([Ca(2+)]cyt) increase in isolated trophozoites, indicating that CZ mobilizes intracellular sources of calcium. In the same extracellular Ca(2+)-free conditions, the [Ca(2+)]cyt rise elicited by CZ treatment was ~3.5 fold higher when the endoplasmic reticulum (ER) calcium store was previously depleted ruling out the mobilization of calcium from the ER by CZ. The effects of the Ca(2+)/H(+) ionophore ionomycin (ION) and the Na(+)/H(+) ionophore monensin (MON) suggest that the [Ca(2+)]cyt-increasing effect of CZ is driven by the removal of Ca(2+) from at least one Ca(2+)-CaM-related (CaMR) protein as well as by the mobilization of Ca(2+) from intracellular acidic calcium stores. Moreover, we showed that the mitochondrion participates in the sequestration of the cytosolic Ca(2+) elicited by CZ. Finally, the modulation of membrane Ca(2+) channels by CZ and thapsigargin (THG) was demonstrated. The opened channels were blocked by the unspecific calcium channel blocker Co(2+) but not by 2-APB (capacitative calcium entry inhibitor) or nifedipine (L-type Ca(2+) channel inhibitor). Taken together, the results suggested that one CaMR protein is an important modulator of calcium signaling and homeostasis during the Plasmodium intraerythrocytic cell cycle, working as a relevant intracellular Ca(2+) reservoir in the parasite.
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Affiliation(s)
- Alexandre Budu
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Mayrim M Gomes
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil
| | - Pollyana M Melo
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Sarah El Chamy Maluf
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Piero Bagnaresi
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Mauro F Azevedo
- Instituto de Ciências Biomédicas, Universidade de São Paulo, SP, Brazil
| | - Adriana K Carmona
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
| | - Marcos L Gazarini
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil.
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203
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McHugh E, Batinovic S, Hanssen E, McMillan PJ, Kenny S, Griffin MD, Crawford S, Trenholme KR, Gardiner DL, Dixon MWA, Tilley L. A repeat sequence domain of the ring-exported protein-1 of Plasmodium falciparum controls export machinery architecture and virulence protein trafficking. Mol Microbiol 2015; 98:1101-14. [PMID: 26304012 PMCID: PMC4987487 DOI: 10.1111/mmi.13201] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2015] [Indexed: 11/30/2022]
Abstract
The malaria parasite Plasmodium falciparum dramatically remodels its host red blood cell to enhance its own survival, using a secretory membrane system that it establishes outside its own cell. Cisternal organelles, called Maurer's clefts, act as a staging point for the forward trafficking of virulence proteins to the red blood cell (RBC) membrane. The Ring-EXported Protein-1 (REX1) is a Maurer's cleft resident protein. We show that inducible knockdown of REX1 causes stacking of Maurer's cleft cisternae without disrupting the organization of the knob-associated histidine-rich protein at the RBC membrane. Genetic dissection of the REX1 sequence shows that loss of a repeat sequence domain results in the formation of giant Maurer's cleft stacks. The stacked Maurer's clefts are decorated with tether-like structures and retain the ability to dock onto the RBC membrane skeleton. The REX1 mutant parasites show deficient export of the major virulence protein, PfEMP1, to the red blood cell surface and markedly reduced binding to the endothelial cell receptor, CD36. REX1 is predicted to form a largely α-helical structure, with a repetitive charge pattern in the repeat sequence domain, providing potential insights into the role of REX1 in Maurer's cleft sculpting.
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Affiliation(s)
- Emma McHugh
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Steven Batinovic
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Eric Hanssen
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
- Advanced Microscopy Facility, University of Melbourne, Parkville, VIC 3010, Australia
| | - Paul J. McMillan
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
- Biological Optical Microscopy Platform, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Shannon Kenny
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michael D.W. Griffin
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Simon Crawford
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Katharine R. Trenholme
- Infectious Diseases Division, Queensland Institute of Medical Research, 300 Herston Rd, Herston, QLD 4006, Australia
| | - Donald L. Gardiner
- Infectious Diseases Division, Queensland Institute of Medical Research, 300 Herston Rd, Herston, QLD 4006, Australia
| | - Matthew W. A. Dixon
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
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204
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Coffey MJ, Sleebs BE, Uboldi AD, Garnham A, Franco M, Marino ND, Panas MW, Ferguson DJP, Enciso M, O'Neill MT, Lopaticki S, Stewart RJ, Dewson G, Smyth GK, Smith BJ, Masters SL, Boothroyd JC, Boddey JA, Tonkin CJ. An aspartyl protease defines a novel pathway for export of Toxoplasma proteins into the host cell. eLife 2015; 4:e10809. [PMID: 26576949 PMCID: PMC4764566 DOI: 10.7554/elife.10809] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/18/2015] [Indexed: 02/03/2023] Open
Abstract
Infection by Toxoplasma gondii leads to massive changes to the host cell. Here, we identify a novel host cell effector export pathway that requires the Golgi-resident aspartyl protease 5 (ASP5). We demonstrate that ASP5 cleaves a highly constrained amino acid motif that has similarity to the PEXEL-motif of Plasmodium parasites. We show that ASP5 matures substrates at both the N- and C-terminal ends of proteins and also controls trafficking of effectors without this motif. Furthermore, ASP5 controls establishment of the nanotubular network and is required for the efficient recruitment of host mitochondria to the vacuole. Assessment of host gene expression reveals that the ASP5-dependent pathway influences thousands of the transcriptional changes that Toxoplasma imparts on its host cell. All these changes result in attenuation of virulence of Δasp5 tachyzoites in vivo. This work characterizes the first identified machinery required for export of Toxoplasma effectors into the infected host cell.
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Affiliation(s)
- Michael J Coffey
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Alessandro D Uboldi
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Alexandra Garnham
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Magdalena Franco
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - Nicole D Marino
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - Michael W Panas
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - David JP Ferguson
- Nuffield Department of Clinical Laboratory Science, Oxford University, John Radcliffe Hospital, Oxford, United Kingdom
| | - Marta Enciso
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Matthew T O'Neill
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Rebecca J Stewart
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Grant Dewson
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Gordon K Smyth
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia
| | - Brian J Smith
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Seth L Masters
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - John C Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - Justin A Boddey
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Christopher J Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
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205
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Abstract
Plasmodium falciparum is the protozoan parasite that causes most malaria-associated morbidity and mortality in humans with over 500,000 deaths annually. The disease symptoms are associated with repeated cycles of invasion and asexual multiplication inside red blood cells of the parasite. Partial, non-sterile immunity to P. falciparum malaria develops only after repeated infections and continuous exposure. The successful evasion of the human immune system relies on the large repertoire of antigenically diverse parasite proteins displayed on the red blood cell surface and on the merozoite membrane where they are exposed to the human immune system. Expression switching of these polymorphic proteins between asexual parasite generations provides an efficient mechanism to adapt to the changing environment in the host and to maintain chronic infection. This chapter discusses antigenic diversity and variation in the malaria parasite and our current understanding of the molecular mechanisms that direct the expression of these proteins.
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Affiliation(s)
- Michaela Petter
- Department of Medicine Royal Melbourne Hospital, Peter Doherty Institute, University of Melbourne, 792 Elizabeth Street, Melbourne, VIC, 3010, Australia.
| | - Michael F Duffy
- Department of Medicine Royal Melbourne Hospital, Peter Doherty Institute, University of Melbourne, 792 Elizabeth Street, Melbourne, VIC, 3010, Australia.
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206
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Kagaya W, Miyazaki S, Yahata K, Ohta N, Kaneko O. The Cytoplasmic Region of Plasmodium falciparum SURFIN4.2 Is Required for Transport from Maurer's Clefts to the Red Blood Cell Surface. Trop Med Health 2015; 43:265-72. [PMID: 26865830 PMCID: PMC4689606 DOI: 10.2149/tmh.2015-38] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 10/28/2015] [Indexed: 12/22/2022] Open
Abstract
Background: Plasmodium, the causative agent of malaria, exports many proteins to the surface of the infected red blood cell (iRBC) in order to modify it toward a structure more suitable for parasite development and survival. One such exported protein, SURFIN4.2, from the parasite of human malignant malaria, P. falciparum, was identified in the trypsin-cleaved protein fraction from the iRBC surface, and is thereby inferred to be exposed on the iRBC surface. SURFIN4.2 also localize to Maurer’s clefts—parasite-derived membranous structures established in the RBC cytoplasm and tethered to the RBC membrane—and their role in trafficking suggests that they are a pathway for SURFIN4.2 transport to the iRBC surface. It has not been determined the participation of protein domains and motifs within SURFIN4.2 in transport from Maurer’s clefts to the iRBC surface; and herein we examined if the SURFIN4.2 intracellular region containing tryptophan-rich (WR) domain is required for its exposure on the iRBC surface. Results: We generated two transgenic parasite lines which express modified SURFIN4.2, with or without a part of the intracellular region. Both recombinant SURFIN4.2 proteins were exported to Maurer’s clefts. However, only SURFIN4.2 possessing the intracellular region was efficiently cleaved by surface treatment of iRBC with proteinase K. Conclusions: These results indicate that SURFIN4.2 is exposed on the iRBC surface and that the intracellular region containing WR domain plays a role on the transport from Maurer’s clefts to the iRBC membrane.
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Affiliation(s)
- Wataru Kagaya
- Section of Environmental Parasitology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo 113-0034, Japan; Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Shinya Miyazaki
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University , Nagasaki, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Kazuhide Yahata
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University , Nagasaki, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Nobuo Ohta
- Section of Environmental Parasitology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University , 1-5-45 Yushima, Bunkyo, Tokyo 113-0034, Japan
| | - Osamu Kaneko
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University , Nagasaki, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
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207
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Kalanon M, Bargieri D, Sturm A, Matthews K, Ghosh S, Goodman CD, Thiberge S, Mollard V, McFadden GI, Ménard R, Koning‐Ward TF. The
Plasmodium
translocon of exported proteins component EXP2 is critical for establishing a patent malaria infection in mice. Cell Microbiol 2015; 18:399-412. [DOI: 10.1111/cmi.12520] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/26/2015] [Accepted: 08/31/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Ming Kalanon
- Molecular and Medical Research Unit, School of MedicineDeakin University Waurn Ponds Geelong Victoria 3216 Australia
| | - Daniel Bargieri
- Unité de Biologie et Génétique du PaludismeInstitut Pasteur Paris France
- Department of Parasitology, Institute of Biomedical SciencesUniversity of São Paulo São Paulo SP Brazil
| | - Angelika Sturm
- School of BioSciencesThe University of Melbourne Parkville Victoria 3010 Australia
| | - Kathryn Matthews
- Molecular and Medical Research Unit, School of MedicineDeakin University Waurn Ponds Geelong Victoria 3216 Australia
| | - Sreejoyee Ghosh
- Molecular and Medical Research Unit, School of MedicineDeakin University Waurn Ponds Geelong Victoria 3216 Australia
| | | | - Sabine Thiberge
- Unité de Biologie et Génétique du PaludismeInstitut Pasteur Paris France
| | - Vanessa Mollard
- School of BioSciencesThe University of Melbourne Parkville Victoria 3010 Australia
| | - Geoffrey I. McFadden
- School of BioSciencesThe University of Melbourne Parkville Victoria 3010 Australia
| | - Robert Ménard
- Unité de Biologie et Génétique du PaludismeInstitut Pasteur Paris France
| | - Tania F. Koning‐Ward
- Molecular and Medical Research Unit, School of MedicineDeakin University Waurn Ponds Geelong Victoria 3216 Australia
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208
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Spielmann T, Gilberger TW. Critical Steps in Protein Export of Plasmodium falciparum Blood Stages. Trends Parasitol 2015; 31:514-525. [DOI: 10.1016/j.pt.2015.06.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/16/2015] [Accepted: 06/24/2015] [Indexed: 11/29/2022]
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209
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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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210
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AhYoung AP, Koehl A, Cascio D, Egea PF. Structural mapping of the ClpB ATPases of Plasmodium falciparum: Targeting protein folding and secretion for antimalarial drug design. Protein Sci 2015; 24:1508-20. [PMID: 26130467 DOI: 10.1002/pro.2739] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 06/24/2015] [Accepted: 06/26/2015] [Indexed: 11/08/2022]
Abstract
Caseinolytic chaperones and proteases (Clp) belong to the AAA+ protein superfamily and are part of the protein quality control machinery in cells. The eukaryotic parasite Plasmodium falciparum, the causative agent of malaria, has evolved an elaborate network of Clp proteins including two distinct ClpB ATPases. ClpB1 and ClpB2 are involved in different aspects of parasitic proteostasis. ClpB1 is present in the apicoplast, a parasite-specific and plastid-like organelle hosting various metabolic pathways necessary for parasite growth. ClpB2 localizes to the parasitophorous vacuole membrane where it drives protein export as core subunit of a parasite-derived protein secretion complex, the Plasmodium Translocon of Exported proteins (PTEX); this process is central to parasite virulence and survival in the human host. The functional associations of these two chaperones with parasite-specific metabolism and protein secretion make them prime drug targets. ClpB proteins function as unfoldases and disaggregases and share a common architecture consisting of four domains-a variable N-terminal domain that binds different protein substrates, followed by two highly conserved catalytic ATPase domains, and a C-terminal domain. Here, we report and compare the first crystal structures of the N terminal domains of ClpB1 and ClpB2 from Plasmodium and analyze their molecular surfaces. Solution scattering analysis of the N domain of ClpB2 shows that the average solution conformation is similar to the crystalline structure. These structures represent the first step towards the characterization of these two malarial chaperones and the reconstitution of the entire PTEX to aid structure-based design of novel anti-malarial drugs.
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Affiliation(s)
- Andrew P AhYoung
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Antoine Koehl
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Duilio Cascio
- Department of Energy Institute for Genomics and Proteomics, UCLA, Los Angeles, California
| | - Pascal F Egea
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, California.,Molecular Biology Institute, UCLA, Los Angeles, California
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211
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Baumeister S, Gangopadhyay P, Repnik U, Lingelbach K. Novel insights into red blood cell physiology using parasites as tools. Eur J Cell Biol 2015; 94:332-9. [DOI: 10.1016/j.ejcb.2015.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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212
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Przyborski JM, Diehl M, Blatch GL. Plasmodial HSP70s are functionally adapted to the malaria parasite life cycle. Front Mol Biosci 2015; 2:34. [PMID: 26167469 PMCID: PMC4481151 DOI: 10.3389/fmolb.2015.00034] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/12/2015] [Indexed: 11/13/2022] Open
Abstract
The human malaria parasite, Plasmodium falciparum, encodes a minimal complement of six heat shock protein 70s (PfHSP70s), some of which are highly expressed and are thought to play an important role in the survival and pathology of the parasite. In addition to canonical features of molecular chaperones, these HSP70s possess properties that reflect functional adaptation to a parasitic life style, including resistance to thermal insult during fever periods and host–parasite interactions. The parasite even exports an HSP70 to the host cell where it is likely to be involved in host cell modification. This review focuses on the features of the PfHSP70s, particularly with respect to their adaptation to the malaria parasite life cycle.
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Affiliation(s)
| | - Mathias Diehl
- Parasitology, Philipps University Marburg Marburg, Germany
| | - Gregory L Blatch
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University Melbourne, VIC, Australia ; Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes University Grahamstown, South Africa
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213
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Cheng Y, Lu F, Lee SK, Kong DH, Ha KS, Wang B, Sattabongkot J, Tsuboi T, Han ET. Characterization of Plasmodium vivax Early Transcribed Membrane Protein 11.2 and Exported Protein 1. PLoS One 2015; 10:e0127500. [PMID: 26011536 PMCID: PMC4444142 DOI: 10.1371/journal.pone.0127500] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 04/16/2015] [Indexed: 12/17/2022] Open
Abstract
In Plasmodium, the membrane of intracellular parasites is initially formed during invasion as an invagination of the red blood cell surface, which forms a barrier between the parasite and infected red blood cells in asexual blood stage parasites. The membrane proteins of intracellular parasites of Plasmodium species have been identified such as early-transcribed membrane proteins (ETRAMPs) and exported proteins (EXPs). However, there is little or no information regarding the intracellular parasite membrane in Plasmodium vivax. In the present study, recombinant PvETRAMP11.2 (PVX_003565) and PvEXP1 (PVX_091700) were expressed and evaluated antigenicity tests using sera from P. vivax-infected patients. A large proportion of infected individuals presented with IgG antibody responses against PvETRAMP11.2 (76.8%) and PvEXP1 (69.6%). Both of the recombinant proteins elicited high antibody titers capable of recognizing parasites of vivax malaria patients. PvETRAMP11.2 partially co-localized with PvEXP1 on the intracellular membranes of immature schizont. Moreover, they were also detected at the apical organelles of newly formed merozoites of mature schizont. We first proposed that these proteins might be synthesized in the preceding schizont stage, localized on the parasite membranes and apical organelles of infected erythrocytes, and induced high IgG antibody responses in patients.
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Affiliation(s)
- Yang Cheng
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Rockville, Maryland, United States of America
| | - Feng Lu
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
- Key Laboratory of Parasitic Disease Control and Prevention (Ministry of Health), Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu Province, People’s Republic of China
- Jiangsu Provincial Key Laboratory of Parasite Molecular Biology, Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu Province, People’s Republic of China
| | - Seong-Kyun Lee
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Deok-Hoon Kong
- Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Kwon-Soo Ha
- Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Bo Wang
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
- Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People’s Republic of China
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
- * E-mail: (ETH); (TT)
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
- * E-mail: (ETH); (TT)
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214
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Schulze J, Kwiatkowski M, Borner J, Schlüter H, Bruchhaus I, Burmester T, Spielmann T, Pick C. The Plasmodium falciparum exportome contains non-canonical PEXEL/HT proteins. Mol Microbiol 2015; 97:301-14. [PMID: 25850860 DOI: 10.1111/mmi.13024] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2015] [Indexed: 11/29/2022]
Abstract
The pathogenicity of Plasmodium falciparum is partly due to parasite-induced host cell modifications. These modifications are facilitated by exported P. falciparum proteins, collectively referred to as the exportome. Export of several hundred proteins is mediated by the PEXEL/HT, a protease cleavage site. The PEXEL/HT is usually comprised of five amino acids, of which R at position 1, L at position 3 and E, D or Q at position 5 are conserved and important for export. Non-canonical PEXEL/HTs with K or H at position 1 and/or I at position 3 are presently considered non-functional. Here, we show that non-canonical PEXEL/HT proteins are overrepresented in P. falciparum and other Plasmodium species. Furthermore, we show that non-canonical PEXEL/HTs can be cleaved and can promote export in both a REX3 and a GBP reporter, but not in a KAHRP reporter, indicating that non-canonical PEXEL/HTs are functional in concert with a supportive sequence environment. We then selected P. falciparum proteins with a non-canonical PEXEL/HT and show that some of these proteins are exported and that their export depends on non-canonical PEXEL/HTs. We conclude that PEXEL/HT plasticity is higher than appreciated and that non-canonical PEXEL/HT proteins cannot categorically be excluded from Plasmodium exportome predictions.
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Affiliation(s)
- Jana Schulze
- University of Hamburg, Institute of Zoology, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany
| | - Marcel Kwiatkowski
- Department of Clinical Chemistry, University Medical Center Hamburg-Eppendorf, D-20246, Hamburg, Germany
| | - Janus Borner
- University of Hamburg, Institute of Zoology, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany
| | - Hartmut Schlüter
- Department of Clinical Chemistry, University Medical Center Hamburg-Eppendorf, D-20246, Hamburg, Germany
| | - Iris Bruchhaus
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, D-20359, Hamburg, Germany
| | - Thorsten Burmester
- University of Hamburg, Institute of Zoology, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany
| | - Tobias Spielmann
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, D-20359, Hamburg, Germany
| | - Christian Pick
- University of Hamburg, Institute of Zoology, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany
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215
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Dent AE, Nakajima R, Liang L, Baum E, Moormann AM, Sumba PO, Vulule J, Babineau D, Randall A, Davies DH, Felgner PL, Kazura JW. Plasmodium falciparum Protein Microarray Antibody Profiles Correlate With Protection From Symptomatic Malaria in Kenya. J Infect Dis 2015; 212:1429-38. [PMID: 25883384 DOI: 10.1093/infdis/jiv224] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/25/2015] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Immunoglobulin G antibodies (Abs) to Plasmodium falciparum antigens have been associated with naturally acquired immunity to symptomatic malaria. METHODS We probed protein microarrays covering 824 unique P. falciparum protein features with plasma from residents of a community in Kenya monitored for 12 weeks for (re)infection and symptomatic malaria after administration of antimalarial drugs. P. falciparum proteins recognized by Abs from 88 children (aged 1-14 years) and 86 adults (aged ≥ 18 years), measured at the beginning of the observation period, were ranked by Ab signal intensity. RESULTS Abs from immune adults reacted with a total 163 of 824 P. falciparum proteins. Children gradually acquired Abs to the full repertoire of antigens recognized by adults. Abs to some antigens showed high seroconversion rates, reaching maximal levels early in childhood, whereas others did not reach adult levels until adolescence. No correlation between Ab signal intensity and time to (re)infection was observed. In contrast, Ab levels to 106 antigens were significantly higher in children who were protected from symptomatic malaria compared with those who were not. Abs to antigens predictive of protection included P. falciparum erythrocyte membrane protein 1, merozoite surface protein (MSP) 10, MSP2, liver-stage antigen 3, PF70, MSP7, and Plasmodium helical interspersed subtelomeric domain protein. CONCLUSIONS Protein microarrays may be useful in the search for malaria antigens associated with protective immunity.
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Affiliation(s)
- Arlene E Dent
- Center for Global Health and Diseases, Case Western Reserve University Rainbow Babies and Children's Hospital, Cleveland, Ohio
| | | | - Li Liang
- University of California, Irvine
| | | | - Ann M Moormann
- Center for Global Health Research, University of Massachusetts Medical School, Worcester
| | | | | | | | | | | | | | - James W Kazura
- Center for Global Health and Diseases, Case Western Reserve University
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216
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In Vivo Function of PTEX88 in Malaria Parasite Sequestration and Virulence. EUKARYOTIC CELL 2015; 14:528-34. [PMID: 25820521 DOI: 10.1128/ec.00276-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/25/2015] [Indexed: 01/07/2023]
Abstract
Malaria pathology is linked to remodeling of red blood cells by eukaryotic Plasmodium parasites. Central to host cell refurbishment is the trafficking of parasite-encoded virulence factors through the Plasmodium translocon of exported proteins (PTEX). Much of our understanding of its function is based on experimental work with cultured Plasmodium falciparum, yet direct consequences of PTEX impairment during an infection remain poorly defined. Using the murine malaria model parasite Plasmodium berghei, it is shown here that efficient sequestration to the pulmonary, adipose, and brain tissue vasculature is dependent on the PTEX components thioredoxin 2 (TRX2) and PTEX88. While TRX2-deficient parasites remain virulent, PTEX88-deficient parasites no longer sequester in the brain, correlating with abolishment of cerebral complications in infected mice. However, an apparent trade-off for virulence attenuation was spleen enlargement, which correlates with a strongly reduced schizont-to-ring-stage transition. Strikingly, general protein export is unaffected in PTEX88-deficient mutants that mature normally in vitro. Thus, PTEX88 is pivotal for tissue sequestration in vivo, parasite virulence, and preventing exacerbation of spleen pathology, but these functions do not correlate with general protein export to the host erythrocyte. The presented data suggest that the protein export machinery of Plasmodium parasites and their underlying mechanistic features are considerably more complex than previously anticipated and indicate challenges for targeted intervention strategies.
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217
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Mbengue A, Vialla E, Berry L, Fall G, Audiger N, Demettre-Verceil E, Boteller D, Braun-Breton C. New Export Pathway inPlasmodium falciparum-Infected Erythrocytes: Role of the Parasite Group II Chaperonin, PfTRiC. Traffic 2015; 16:461-75. [DOI: 10.1111/tra.12266] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Alassane Mbengue
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Emilie Vialla
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Laurence Berry
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Gamou Fall
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Nicolas Audiger
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Edith Demettre-Verceil
- Plate-forme de Protéomique Fonctionnelle - FPP; UMS CNRS 3426 - US 009 INSERM - UMI - UMII, IGF; 141 rue de la Cardonille 34094 Montpellier Cedex 5 France
| | - David Boteller
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Catherine Braun-Breton
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
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218
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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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219
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Spillman NJ, Beck JR, Goldberg DE. Protein export into malaria parasite-infected erythrocytes: mechanisms and functional consequences. Annu Rev Biochem 2015; 84:813-41. [PMID: 25621510 DOI: 10.1146/annurev-biochem-060614-034157] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phylum Apicomplexa comprises a large group of obligate intracellular parasites of high medical and veterinary importance. These organisms succeed intracellularly by effecting remarkable changes in a broad range of diverse host cells. The transformation of the host erythrocyte is particularly striking in the case of the malaria parasite Plasmodium falciparum. P. falciparum exports hundreds of proteins that mediate a complex cellular renovation marked by changes in the permeability, rigidity, and cytoadherence properties of the host erythrocyte. The past decade has seen enormous progress in understanding the identity and function of these exported effectors, as well as the mechanisms by which they are trafficked into the host cell. Here we review these advances, place them in the context of host manipulation by related apicomplexans, and propose key directions for future research.
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220
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Gazdik M, O'Neill MT, Lopaticki S, Lowes KN, Smith BJ, Cowman AF, Boddey JA, Sleebs BE. The effect of N-methylation on transition state mimetic inhibitors of the Plasmodium protease, plasmepsin V. MEDCHEMCOMM 2015. [DOI: 10.1039/c4md00409d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An N-methylation strategy has been applied to transition state mimetics that are potent inhibitors of plasmepsin V to improve their physical characteristics and their ability to reduce the viability of Plasmodium parasites in culture.
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Affiliation(s)
- Michelle Gazdik
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | - Matthew T. O'Neill
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | - Kym N. Lowes
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | | | - Alan F. Cowman
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | - Justin A. Boddey
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | - Brad E. Sleebs
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
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221
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Pesce ER, Blatch GL, Edkins AL. Hsp40 Co-chaperones as Drug Targets: Towards the Development of Specific Inhibitors. TOPICS IN MEDICINAL CHEMISTRY 2015. [DOI: 10.1007/7355_2015_92] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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222
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Peng M, Cascio D, Egea PF. Crystal structure and solution characterization of the thioredoxin-2 from Plasmodium falciparum, a constituent of an essential parasitic protein export complex. Biochem Biophys Res Commun 2014; 456:403-9. [PMID: 25475729 DOI: 10.1016/j.bbrc.2014.11.096] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 11/24/2014] [Indexed: 10/24/2022]
Abstract
Survival of the malaria parasite Plasmodium falciparum when it infects red blood cells depends upon its ability to export hundreds of its proteins beyond an encasing vacuole. Protein export is mediated by a parasite-derived protein complex, the Plasmodium translocon of exported proteins (PTEX), and requires unfolding of the different cargos prior to their translocation across the vacuolar membrane. Unfolding is performed by the AAA+protein unfoldase HSP101/ClpB2 and the thioredoxin-2 enzyme (TRX2). Protein trafficking is dramatically impaired in parasites with defective HSP101 or lacking TRX2. These two PTEX subunits drive export and are targets for the design of a novel class of antimalarials: protein export inhibitors. To rationalize inhibitor design, we solved the crystal structure of Pfal-TRX2 at 2.2-Å resolution. Within the asymmetric unit, the three different copies of this protein disulfide reductase sample its two redox catalytic states. Size exclusion chromatography and small-angle X-ray scattering (SAXS) analyses demonstrate that Pfal-TRX2 is monomeric in solution. A non-conserved N-terminal extension precedes the canonical thioredoxin-fold; although it is not observed in our structure, our solution analysis suggests it is flexible in contrast to Plasmodium thioredoxin-1. This represents a first step towards the reconstitution of the entire PTEX for mechanistic and structural studies.
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Affiliation(s)
- Mindy Peng
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, USA
| | - Duilio Cascio
- Department of Energy Institute for Genomics and Proteomics, UCLA, Los Angeles, USA
| | - Pascal F Egea
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, USA; Molecular Biology Institute, UCLA, Los Angeles, CA, USA.
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224
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Plasmodium falciparum transfected with ultra bright NanoLuc luciferase offers high sensitivity detection for the screening of growth and cellular trafficking inhibitors. PLoS One 2014; 9:e112571. [PMID: 25392998 PMCID: PMC4231029 DOI: 10.1371/journal.pone.0112571] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/08/2014] [Indexed: 11/19/2022] Open
Abstract
Drug discovery is a key part of malaria control and eradication strategies, and could benefit from sensitive and affordable assays to quantify parasite growth and to help identify the targets of potential anti-malarial compounds. Bioluminescence, achieved through expression of exogenous luciferases, is a powerful tool that has been applied in studies of several aspects of parasite biology and high throughput growth assays. We have expressed the new reporter NanoLuc (Nluc) luciferase in Plasmodium falciparum and showed it is at least 100 times brighter than the commonly used firefly luciferase. Nluc brightness was explored as a means to achieve a growth assay with higher sensitivity and lower cost. In addition we attempted to develop other screening assays that may help interrogate libraries of inhibitory compounds for their mechanism of action. To this end parasites were engineered to express Nluc in the cytoplasm, the parasitophorous vacuole that surrounds the intraerythrocytic parasite or exported to the red blood cell cytosol. As proof-of-concept, these parasites were used to develop functional screening assays for quantifying the effects of Brefeldin A, an inhibitor of protein secretion, and Furosemide, an inhibitor of new permeation pathways used by parasites to acquire plasma nutrients.
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225
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Abstract
Eukaryotic, prokaryotic and viral pathogens are known to interfere with signaling pathways of their host to promote their own survival and proliferation. Here, we present selected examples of modulation of PAK activity in human cells by both intracellular and extracellular pathogens, focusing on one eukaryotic pathogen, the human malaria parasite Plasmodium falciparum, two Gram-negative bacteria (Helicobacter pylori and Pseudomonas aeruginosa), and two viruses belonging to distinct groups, the lentivirus HIV and the orthomyxovirus Influenza virus A.
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226
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Webster WAJ, McFadden GI. From the genome to the phenome: tools to understand the basic biology of Plasmodium falciparum. J Eukaryot Microbiol 2014; 61:655-71. [PMID: 25227912 DOI: 10.1111/jeu.12176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
Abstract
Malaria plagues one out of every 30 humans and contributes to almost a million deaths, and the problem could worsen. Our current therapeutic options are compromised by emerging resistance by the parasite to our front line drugs. It is thus imperative to better understand the basic biology of the parasite and develop novel drugs to stem this disease. The most facile approach to analyse a gene's function is to remove it from the genome or inhibit its activity. Although genetic manipulation of the human malaria parasite Plasmodium falciparum is a relatively standard procedure, there is no optimal method to perturb genes essential to the intraerythrocytic development cycle--the part of the life cycle that produces the clinical manifestation of malaria. This is a severe impediment to progress because the phenotype we wish to study is exactly the one that is so elusive. In the absence of any utilitarian way to conditionally delete essential genes, we are prevented from investigating the parasite's most vulnerable points. This review aims to focus on the development of tools identifying essential genes of P. falciparum and our ability to elicit phenotypic mutation.
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Affiliation(s)
- Wesley A J Webster
- Centre for Regional and Rural Futures, School of Life and Environmental Sciences, Deakin University, Burwood, 3125, Victoria, Australia; Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Melbourne, 3010, Victoria, Australia
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227
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Erythrocyte lysis and Xenopus laevis oocyte rupture by recombinant Plasmodium falciparum hemolysin III. EUKARYOTIC CELL 2014; 13:1337-45. [PMID: 25148832 DOI: 10.1128/ec.00088-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Malaria kills more than 1 million people per year worldwide, with severe malaria anemia accounting for the majority of the deaths. Malaria anemia is multifactorial in etiology, including infected erythrocyte destruction and decrease in erythrocyte production, as well as destruction or clearance of noninfected erythrocytes. We identified a panspecies Plasmodium hemolysin type III related to bacterial hemolysins. The identification of a hemolysin III homologue in Plasmodium suggests a potential role in host erythrocyte lysis. Here, we report the first characterization of Plasmodium falciparum hemolysin III, showing that the soluble recombinant P. falciparum hemolysin III is a pore-forming protein capable of lysing human erythrocytes in a dose-, time-, and temperature-dependent fashion. The recombinant P. falciparum hemolysin III-induced hemolysis was partially inhibited by glibenclamide, a known channel antagonist. Studies with polyethylene glycol molecules of different molecular weights indicated a pore size of approximately 3.2 nm. Heterologous expression of recombinant P. falciparum hemolysin III in Xenopus oocytes demonstrated early hypotonic lysis similar to that of the pore-forming aquaporin control. Live fluorescence microscopy localized transfected recombinant green fluorescent protein (GFP)-tagged P. falciparum hemolysin III to the essential digestive vacuole of the P. falciparum parasite. These transfected trophozoites also possessed a swollen digestive vacuole phenotype. Native Plasmodium hemolysin III in the digestive vacuole may contribute to lysis of the parasitophorous vacuole membrane derived from the host erythrocyte. After merozoite egress from infected erythrocytes, remnant P. falciparum hemolysin III released from digestive vacuoles could potentially contribute to lysis of uninfected erythrocytes to contribute to severe life-threatening anemia.
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228
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Export of virulence proteins by malaria-infected erythrocytes involves remodeling of host actin cytoskeleton. Blood 2014; 124:3459-68. [PMID: 25139348 DOI: 10.1182/blood-2014-06-583054] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Following invasion of human red blood cells (RBCs) by the malaria parasite, Plasmodium falciparum, a remarkable process of remodeling occurs in the host cell mediated by trafficking of several hundred effector proteins to the RBC compartment. The exported virulence protein, P falciparum erythrocyte membrane protein 1 (PfEMP1), is responsible for cytoadherence of infected cells to host endothelial receptors. Maurer clefts are organelles essential for protein trafficking, sorting, and assembly of protein complexes. Here we demonstrate that disruption of PfEMP1 trafficking protein 1 (PfPTP1) function leads to severe alterations in the architecture of Maurer's clefts. Furthermore, 2 major surface antigen families, PfEMP1 and STEVOR, are no longer displayed on the host cell surface leading to ablation of cytoadherence to host receptors. PfPTP1 functions in a large complex of proteins and is required for linking of Maurer's clefts to the host actin cytoskeleton.
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229
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Tarr SJ, Moon RW, Hardege I, Osborne AR. A conserved domain targets exported PHISTb family proteins to the periphery of Plasmodium infected erythrocytes. Mol Biochem Parasitol 2014; 196:29-40. [PMID: 25106850 PMCID: PMC4165601 DOI: 10.1016/j.molbiopara.2014.07.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/24/2014] [Accepted: 07/28/2014] [Indexed: 11/19/2022]
Abstract
Multiple P. falciparum PHISTb proteins localise to the erythrocyte periphery. Solubility profiling indicates that these proteins associate with the red cell cytoskeleton. The PRESAN domain and a preceding N-terminal sequence is a novel targeting domain. A protein targeted to the red cell periphery is essential for parasite survival. P. knowlesi and P. vivax homologous domains also confer similar localisation.
During blood-stage infection, malaria parasites export numerous proteins to the host erythrocyte. The Poly-Helical Interspersed Sub-Telomeric (PHIST) proteins are an exported family that share a common ‘PRESAN’ domain, and include numerous members in Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi. In P. falciparum, PHIST proteins have been implicated in protein trafficking and intercellular communication. A number of PHIST proteins are essential for parasite survival. Here, we identify nine members of the PHISTb sub-class of PHIST proteins, including one protein known to be essential for parasite survival, that localise to the erythrocyte periphery. These proteins have solubility characteristics consistent with their association with the erythrocyte cytoskeleton. Together, an extended PRESAN domain, comprising the PRESAN domain and preceding sequence, form a novel targeting-domain that is sufficient to localise a protein to the erythrocyte periphery. We validate the role of this domain in RESA, thus identifying a cytoskeleton-binding domain in RESA that functions independently of its known spectrin-binding domain. Our data suggest that some PHISTb proteins may act as cross-linkers of the erythrocyte cytoskeleton. We also show for the first time that peripherally-localised PHISTb proteins are encoded in genomes of P. knowlesi and vivax indicating a conserved role for the extended PRESAN domain of these proteins in targeting to the erythrocyte periphery.
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Affiliation(s)
- Sarah J Tarr
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, UK
| | - Robert W Moon
- Division of Parasitology, MRC National Institute for Medical Research, London, UK
| | - Iris Hardege
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, UK
| | - Andrew R Osborne
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, UK.
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230
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Prajapati SK, Culleton R, Singh OP. Protein trafficking in Plasmodium falciparum-infected red cells and impact of the expansion of exported protein families. Parasitology 2014; 141:1-11. [PMID: 25076418 DOI: 10.1017/s0031182014000948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARY Erythrocytes are extensively remodelled by the malaria parasite following invasion of the cell. Plasmodium falciparum encodes numerous virulence-associated and host-cell remodelling proteins that are trafficked to the cytoplasm, the cell membrane and the surface of the infected erythrocyte. The export of soluble proteins relies on a sequence directing entry into the secretory pathways in addition to an export signal. The export signal consisting of five amino acids is termed the Plasmodium export element (PEXEL) or the vacuole transport signal (VTS). Genome mining studies have revealed that PEXEL/VTS carrying protein families have expanded dramatically in P. falciparum compared with other malaria parasite species, possibly due to lineage-specific expansion linked to the unique requirements of P. falciparum for host-cell remodelling. The functional characterization of such genes and gene families may reveal potential drug targets that could inhibit protein trafficking in infected erythrocytes. This review highlights some of the recent advances and key knowledge gaps in protein trafficking pathways in P. falciparum-infected red cells and speculates on the impact of exported gene families in the trafficking pathway.
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Affiliation(s)
- Surendra K Prajapati
- Molecular Biology Division,National Institute of Malaria Research,New Delhi,India
| | - Richard Culleton
- Malaria Unit,Institute for Tropical Medicine (NEKKEN), Nagasaki University,Nagasaki,Japan
| | - Om P Singh
- Molecular Biology Division,National Institute of Malaria Research,New Delhi,India
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231
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Beck JR, Muralidharan V, Oksman A, Goldberg DE. PTEX component HSP101 mediates export of diverse malaria effectors into host erythrocytes. Nature 2014; 511:592-5. [PMID: 25043010 PMCID: PMC4130291 DOI: 10.1038/nature13574] [Citation(s) in RCA: 197] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 06/11/2014] [Indexed: 12/02/2022]
Affiliation(s)
- Josh R Beck
- 1] Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, USA [2]
| | - Vasant Muralidharan
- 1] Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA [2] Howard Hughes Medical Institute, Washington University School of Medicine, St Louis, Missouri 63110, USA [3] [4] Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, USA
| | - Anna Oksman
- 1] Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, USA [2] Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA [3] Howard Hughes Medical Institute, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Daniel E Goldberg
- 1] Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, USA [2] Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA [3] Howard Hughes Medical Institute, Washington University School of Medicine, St Louis, Missouri 63110, USA
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Elsworth B, Matthews K, Nie CQ, Kalanon M, Charnaud SC, Sanders PR, Chisholm SA, Counihan NA, Shaw PJ, Pino P, Chan JA, Azevedo MF, Rogerson SJ, Beeson JG, Crabb BS, Gilson PR, de Koning-Ward TF. PTEX is an essential nexus for protein export in malaria parasites. Nature 2014; 511:587-91. [DOI: 10.1038/nature13555] [Citation(s) in RCA: 195] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 05/30/2014] [Indexed: 11/09/2022]
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234
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Baldwin M, Russo C, Li X, Chishti AH. Plasmodium falciparum signal peptide peptidase cleaves malaria heat shock protein 101 (HSP101). Implications for gametocytogenesis. Biochem Biophys Res Commun 2014; 450:1427-32. [PMID: 25017910 DOI: 10.1016/j.bbrc.2014.07.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 07/02/2014] [Indexed: 10/25/2022]
Abstract
Previously we described the identification of a Plasmodium falciparum signal peptide peptidase (PfSPP) functioning at the blood stage of malaria infection. Our studies also demonstrated that mammalian SPP inhibitors prevent malaria parasite growth at the late-ring/early trophozoite stage of intra-erythrocytic development. Consistent with its role in development, we tested the hypothesis that PfSPP functions at the endoplasmic reticulum of P.falciparum where it cleaves membrane-bound signal peptides generated following the enzyme activity of signal peptidase. The localization of PfSPP to the endoplasmic reticulum was confirmed by immunofluorescence microscopy and immunogold electron microscopy. Biochemical analysis indicated the existence of monomer and dimer forms of PfSPP in the parasite lysate. A comprehensive bioinformatics screen identified several candidate PfSPP substrates in the parasite genome. Using an established transfection based in vivo luminescence assay, malaria heat shock protein 101 (HSP101) was identified as a substrate of PfSPP, and partial inhibition of PfSPP correlated with the emergence of gametocytes. This finding unveils the first known substrate of PfSPP, and provides new perspectives for the function of intra-membrane proteolysis at the erythrocyte stage of malaria parasite life cycle.
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Affiliation(s)
- Michael Baldwin
- Department of Developmental, Molecular & Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Crystal Russo
- Department of Developmental, Molecular & Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Xuerong Li
- Department of Developmental, Molecular & Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Athar H Chishti
- Department of Developmental, Molecular & Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, United States; Sackler School of Graduate Biomedical Sciences, Programs in Physiology, Pharmacology, and Microbiology, Tufts University School of Medicine, Boston, MA 02111, United States.
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235
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Oberli A, Slater LM, Cutts E, Brand F, Mundwiler-Pachlatko E, Rusch S, Masik MFG, Erat MC, Beck HP, Vakonakis I. A Plasmodium falciparum PHIST protein binds the virulence factor PfEMP1 and comigrates to knobs on the host cell surface. FASEB J 2014; 28:4420-33. [PMID: 24983468 PMCID: PMC4202109 DOI: 10.1096/fj.14-256057] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Uniquely among malaria parasites, Plasmodium falciparum-infected erythrocytes (iRBCs) develop membrane protrusions, known as knobs, where the parasite adhesion receptor P. falciparum erythrocyte membrane protein 1 (PfEMP1) clusters. Knob formation and the associated iRBC adherence to host endothelium are directly linked to the severity of malaria and are functional manifestations of protein export from the parasite to the iRBC. A family of exported proteins featuring Plasmodium helical interspersed subtelomeric (PHIST) domains has attracted attention, with members being implicated in host-parasite protein interactions and differentially regulated in severe disease and among parasite isolates. Here, we show that PHIST member PFE1605w binds the PfEMP1 intracellular segment directly with Kd = 5 ± 0.6 μM, comigrates with PfEMP1 during export, and locates in knobs. PHIST variants that do not locate in knobs (MAL8P1.4) or bind PfEMP1 30 times more weakly (PFI1780w) used as controls did not display the same pattern. We resolved the first crystallographic structure of a PHIST protein and derived a partial model of the PHIST-PfEMP1 interaction from nuclear magnetic resonance. We propose that PFE1605w reinforces the PfEMP1-cytoskeletal connection in knobs and discuss the possible role of PHIST proteins as interaction hubs in the parasite exportome.
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Affiliation(s)
- Alexander Oberli
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; and
| | - Leanne M Slater
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Erin Cutts
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Françoise Brand
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; and
| | - Esther Mundwiler-Pachlatko
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; and
| | - Sebastian Rusch
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; and
| | | | - Michèle C Erat
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Hans-Peter Beck
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; and
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236
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Tokumasu F, Crivat G, Ackerman H, Hwang J, Wellems TE. Inward cholesterol gradient of the membrane system in P. falciparum-infected erythrocytes involves a dilution effect from parasite-produced lipids. Biol Open 2014; 3:529-41. [PMID: 24876390 PMCID: PMC4058088 DOI: 10.1242/bio.20147732] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum (Pf) infection remodels the human erythrocyte with new membrane systems, including a modified host erythrocyte membrane (EM), a parasitophorous vacuole membrane (PVM), a tubulovesicular network (TVN), and Maurer's clefts (MC). Here we report on the relative cholesterol contents of these membranes in parasitized normal (HbAA) and hemoglobin S-containing (HbAS, HbAS) erythrocytes. Results from fluorescence lifetime imaging microscopy (FLIM) experiments with a cholesterol-sensitive fluorophore show that membrane cholesterol levels in parasitized erythrocytes (pRBC) decrease inwardly from the EM, to the MC/TVN, to the PVM, and finally to the parasite membrane (PM). Cholesterol depletion of pRBC by methyl-β-cyclodextrin treatment caused a collapse of this gradient. Lipid and cholesterol exchange data suggest that the cholesterol gradient involves a dilution effect from non-sterol lipids produced by the parasite. FLIM signals from the PVM or PM showed little or no difference between parasitized HbAA vs HbS-containing erythrocytes that differed in lipid content, suggesting that malaria parasites may regulate the cholesterol contents of the PVM and PM independently of levels in the host cell membrane. Cholesterol levels may affect raft structures and the membrane trafficking and sorting functions that support Pf survival in HbAA, HbAS and HbSS erythrocytes.
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Affiliation(s)
- Fuyuki Tokumasu
- Malaria Genetics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA Present address: Department of Lipidomics, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Georgeta Crivat
- Malaria Genetics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA Quantum Electronics and Photonics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Hans Ackerman
- Malaria Genetics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA
| | - Jeeseong Hwang
- Quantum Electronics and Photonics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Thomas E Wellems
- Malaria Genetics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA
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237
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Chan JA, Fowkes FJI, Beeson JG. Surface antigens of Plasmodium falciparum-infected erythrocytes as immune targets and malaria vaccine candidates. Cell Mol Life Sci 2014; 71:3633-57. [PMID: 24691798 PMCID: PMC4160571 DOI: 10.1007/s00018-014-1614-3] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/04/2014] [Accepted: 03/17/2014] [Indexed: 12/19/2022]
Abstract
Understanding the targets and mechanisms of human immunity to malaria caused by Plasmodium falciparum is crucial for advancing effective vaccines and developing tools for measuring immunity and exposure in populations. Acquired immunity to malaria predominantly targets the blood stage of infection when merozoites of Plasmodium spp. infect erythrocytes and replicate within them. During the intra-erythrocytic development of P. falciparum, numerous parasite-derived antigens are expressed on the surface of infected erythrocytes (IEs). These antigens enable P. falciparum-IEs to adhere in the vasculature and accumulate in multiple organs, which is a key process in the pathogenesis of disease. IE surface antigens, often referred to as variant surface antigens, are important targets of acquired protective immunity and include PfEMP1, RIFIN, STEVOR and SURFIN. These antigens are highly polymorphic and encoded by multigene families, which generate substantial antigenic diversity to mediate immune evasion. The most important immune target appears to be PfEMP1, which is a major ligand for vascular adhesion and sequestration of IEs. Studies are beginning to identify specific variants of PfEMP1 linked to disease pathogenesis that may be suitable for vaccine development, but overcoming antigenic diversity in PfEMP1 remains a major challenge. Much less is known about other surface antigens, or antigens on the surface of gametocyte-IEs, the effector mechanisms that mediate immunity, and how immunity is acquired and maintained over time; these are important topics for future research.
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238
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Kats LM, Fernandez KM, Glenister FK, Herrmann S, Buckingham DW, Siddiqui G, Sharma L, Bamert R, Lucet I, Guillotte M, Mercereau-Puijalon O, Cooke BM. An exported kinase (FIKK4.2) that mediates virulence-associated changes in Plasmodium falciparum-infected red blood cells. Int J Parasitol 2014; 44:319-28. [DOI: 10.1016/j.ijpara.2014.01.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 01/22/2014] [Accepted: 01/22/2014] [Indexed: 11/28/2022]
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Abstract
SUMMARYPlasmodium falciparumdisplays a large and remarkable variety of heat shock protein 40 family members (PfHsp40s). The majority of the PfHsp40s are poorly characterized, and although the functions of some of them have been suggested, their exact mechanism of action is still elusive and their interacting partners and client proteins are unknown. TheP. falciparumheat shock protein 70 family members (PfHsp70s) have been more extensively characterized than the PfHsp40s, with certain members shown to function as molecular chaperones. However, little is known about the PfHsp70-PfHsp40 chaperone partnerships. There is mounting evidence that these chaperones are important not only in protein homoeostasis and cytoprotection, but also in protein trafficking across the parasitophorous vacuole (PV) and into the infected erythrocyte. We propose that certain members of these chaperone families work together to maintain exported proteins in an unfolded state until they reach their final destination. In this review, we critically evaluate what is known and not known about PfHsp40s and PfHsp70s.
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240
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Abstract
As it grows and replicates within the erythrocytes of its host the malaria parasite takes up nutrients from the extracellular medium, exports metabolites and maintains a tight control over its internal ionic composition. These functions are achieved via membrane transport proteins, integral membrane proteins that mediate the passage of solutes across the various membranes that separate the biochemical machinery of the parasite from the extracellular environment. Proteins of this type play a key role in antimalarial drug resistance, as well as being candidate drug targets in their own right. This review provides an overview of recent work on the membrane transport biology of the malaria parasite-infected erythrocyte, encompassing both the parasite-induced changes in the membrane transport properties of the host erythrocyte and the cell physiology of the intracellular parasite itself.
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241
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Elsworth B, Crabb BS, Gilson PR. Protein export in malaria parasites: an update. Cell Microbiol 2014; 16:355-63. [PMID: 24418476 DOI: 10.1111/cmi.12261] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/04/2014] [Accepted: 01/06/2014] [Indexed: 11/30/2022]
Abstract
Symptomatic malaria is caused by the infection of human red blood cells (RBCs) with Plasmodium parasites. The RBC is a peculiar environment for parasites to thrive in as they lack many of the normal cellular processes and resources present in other cells. Because of this, Plasmodium spp. have adapted to extensively remodel the host cell through the export of hundreds of proteins that have a range of functions, the best known of which are virulence-associated. Many exported parasite proteins are themselves involved in generating a novel trafficking system in the RBC that further promotes export. In this review we provide an overview of the parasite synthesized export machinery as well as recent developments in how different classes of exported proteins are recognized by this machinery.
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Affiliation(s)
- Brendan Elsworth
- Burnet Institute, 85 Commercial Road, Melbourne, Vic., 3004, Australia; Monash University, Clayton, Vic., Australia
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242
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Ingmundson A, Alano P, Matuschewski K, Silvestrini F. Feeling at home from arrival to departure: protein export and host cell remodelling during Plasmodium liver stage and gametocyte maturation. Cell Microbiol 2014; 16:324-33. [PMID: 24330249 DOI: 10.1111/cmi.12251] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 12/09/2013] [Accepted: 12/09/2013] [Indexed: 12/19/2022]
Abstract
Obligate intracellular pathogens actively remodel their host cells to boost propagation, survival, and persistence. Plasmodium falciparum, the causative agent of the most severe form of malaria, assembles a complex secretory system in erythrocytes. Export of parasite factors to the erythrocyte membrane is essential for parasite sequestration from the blood circulation and a major factor for clinical complications in falciparum malaria. Historic and recent molecular reports show that host cell remodelling is not exclusive to P. falciparum and that parasite-induced intra-erythrocytic membrane structures and protein export occur in several Plasmodia. Comparative analyses of P. falciparum asexual and sexual blood stages and imaging of liver stages from transgenic murine Plasmodium species show that protein export occurs in all intracellular phases from liver infection to sexual differentiation, indicating that mammalian Plasmodium species evolved efficient strategies to renovate erythrocytes and hepatocytes according to the specific needs of each life cycle phase. While the repertoireof identified exported proteins is remarkably expanded in asexual P. falciparum blood stages, the putative export machinery and known targeting signatures are shared across life cycle stages. A better understanding of the molecular mechanisms underlying Plasmodium protein export could assist in designing novel strategies to interrupt transmission between Anopheles mosquitoes and humans.
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Affiliation(s)
- Alyssa Ingmundson
- Max Planck Institute for Infection Biology, Parasitology Unit, 10117, Berlin, Germany
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243
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Zhang J, Landry MP, Barone PW, Kim JH, Lin S, Ulissi ZW, Lin D, Mu B, Boghossian AA, Hilmer AJ, Rwei A, Hinckley AC, Kruss S, Shandell MA, Nair N, Blake S, Şen F, Şen S, Croy RG, Li D, Yum K, Ahn JH, Jin H, Heller DA, Essigmann JM, Blankschtein D, Strano MS. Molecular recognition using corona phase complexes made of synthetic polymers adsorbed on carbon nanotubes. NATURE NANOTECHNOLOGY 2013; 8:959-68. [PMID: 24270641 PMCID: PMC5051352 DOI: 10.1038/nnano.2013.236] [Citation(s) in RCA: 185] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 10/10/2013] [Indexed: 05/18/2023]
Abstract
Understanding molecular recognition is of fundamental importance in applications such as therapeutics, chemical catalysis and sensor design. The most common recognition motifs involve biological macromolecules such as antibodies and aptamers. The key to biorecognition consists of a unique three-dimensional structure formed by a folded and constrained bioheteropolymer that creates a binding pocket, or an interface, able to recognize a specific molecule. Here, we show that synthetic heteropolymers, once constrained onto a single-walled carbon nanotube by chemical adsorption, also form a new corona phase that exhibits highly selective recognition for specific molecules. To prove the generality of this phenomenon, we report three examples of heteropolymer-nanotube recognition complexes for riboflavin, L-thyroxine and oestradiol. In each case, the recognition was predicted using a two-dimensional thermodynamic model of surface interactions in which the dissociation constants can be tuned by perturbing the chemical structure of the heteropolymer. Moreover, these complexes can be used as new types of spatiotemporal sensors based on modulation of the carbon nanotube photoemission in the near-infrared, as we show by tracking riboflavin diffusion in murine macrophages.
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Affiliation(s)
- Jingqing Zhang
- 1] Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA [2]
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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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245
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Costa JDN, Zanchi FB, Rodrigues FLDS, Honda ER, Katsuragawa TH, Pereira DB, Taborda RLM, Tada MS, Ferreira RDGM, Pereira-da-Silva LH. Cross-reactive anti-PfCLAG9 antibodies in the sera of asymptomatic parasite carriers of Plasmodium vivax. Mem Inst Oswaldo Cruz 2013; 108:98-105. [PMID: 23440122 PMCID: PMC3974312 DOI: 10.1590/s0074-02762013000100016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 10/31/2012] [Indexed: 11/22/2022] Open
Abstract
The PfCLAG9 has been extensively studied because their immunogenicity. Thereby, the gene product is important for therapeutics interventions and a potential vaccine candidate. Antibodies against synthetic peptides corresponding to selected sequences of the Plasmodium falciparum antigen PfCLAG9 were found in sera of falciparum malaria patients from Rondônia, in the Brazilian Amazon. Much higher antibody titres were found in semi-immune and immune asymptomatic parasite carriers than in subjects suffering clinical infections, corroborating original findings in Papua Guinea. However, sera of Plasmodium vivax patients from the same Amazon area, in particular from asymptomatic vivax parasite carriers, reacted strongly with the same peptides. Bioinformatic analyses revealed regions of similarity between P. falciparum Pfclag9 and the P. vivax ortholog Pvclag7. Indirect fluorescent microscopy analysis showed that antibodies against PfCLAG9 peptides elicited in BALB/c mice react with human red blood cells (RBCs) infected with both P. falciparum and P. vivax parasites. The patterns of reactivity on the surface of the parasitised RBCs are very similar. The present observations support previous findings that PfCLAG9 may be a target of protective immune responses and raises the possibility that the cross reactive antibodies to PvCLAG7 in mixed infections play a role in regulate the fate of Plasmodium mixed infections.
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246
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Role of gap junctions and hemichannels in parasitic infections. BIOMED RESEARCH INTERNATIONAL 2013; 2013:589130. [PMID: 24236292 PMCID: PMC3819887 DOI: 10.1155/2013/589130] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/07/2013] [Accepted: 08/26/2013] [Indexed: 02/06/2023]
Abstract
In vertebrates, connexins (Cxs) and pannexins (Panxs) are proteins that form gap junction channels and/or hemichannels located at cell-cell interfaces and cell surface, respectively. Similar channel types are formed by innexins in invertebrate cells. These channels serve as pathways for cellular communication that coordinate diverse physiologic processes. However, it is known that many acquired and inherited diseases deregulate Cx and/or Panx channels, condition that frequently worsens the pathological state of vertebrates. Recent evidences suggest that Cx and/or Panx hemichannels play a relevant role in bacterial and viral infections. Nonetheless, little is known about the role of Cx- and Panx-based channels in parasitic infections of vertebrates. In this review, available data on changes in Cx and gap junction channel changes induced by parasitic infections are summarized. Additionally, we describe recent findings that suggest possible roles of hemichannels in parasitic infections. Finally, the possibility of new therapeutic designs based on hemichannel blokers is presented.
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247
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Palanisamy B, Ekambaram R, Heese K. Thymine distribution in genes provides novel insight into the functional significance of the proteome of the malaria parasite Plasmodium falciparum 3D7. Bioinformatics 2013; 30:597-600. [DOI: 10.1093/bioinformatics/btt587] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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248
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Yam XY, Birago C, Fratini F, Di Girolamo F, Raggi C, Sargiacomo M, Bachi A, Berry L, Fall G, Currà C, Pizzi E, Breton CB, Ponzi M. Proteomic analysis of detergent-resistant membrane microdomains in trophozoite blood stage of the human malaria parasite Plasmodium falciparum. Mol Cell Proteomics 2013; 12:3948-61. [PMID: 24045696 DOI: 10.1074/mcp.m113.029272] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Intracellular pathogens contribute to a significant proportion of infectious diseases worldwide. The successful strategy of evading the immune system by hiding inside host cells is common to all the microorganism classes, which exploit membrane microdomains, enriched in cholesterol and sphingolipids, to invade and colonize the host cell. These assemblies, with distinct biochemical properties, can be isolated by means of flotation in sucrose density gradient centrifugation because they are insoluble in nonionic detergents at low temperature. We analyzed the protein and lipid contents of detergent-resistant membranes from erythrocytes infected by Plasmodium falciparum, the most deadly human malaria parasite. Proteins associated with membrane microdomains of trophic parasite blood stages (trophozoites) include an abundance of chaperones, molecules involved in vesicular trafficking, and enzymes implicated in host hemoglobin degradation. About 60% of the identified proteins contain a predicted localization signal suggesting a role of membrane microdomains in protein sorting/trafficking. To validate our proteomic data, we raised antibodies against six Plasmodium proteins not characterized previously. All the selected candidates were recovered in floating low-density fractions after density gradient centrifugation. The analyzed proteins localized either to internal organelles, such as the mitochondrion and the endoplasmic reticulum, or to exported membrane structures, the parasitophorous vacuole membrane and Maurer's clefts, implicated in targeting parasite proteins to the host erythrocyte cytosol or surface. The relative abundance of cholesterol and phospholipid species varies in gradient fractions containing detergent-resistant membranes, suggesting heterogeneity in the lipid composition of the isolated microdomain population. This study is the first report showing the presence of cholesterol-rich microdomains with distinct properties and subcellular localization in trophic stages of Plasmodium falciparum.
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Affiliation(s)
- Xue Yan Yam
- University Montpellier II, CNRS UMR 5235, 34095 Montpellier, Cedex 5, France
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249
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Boddey JA, Cowman AF. PlasmodiumNesting: Remaking the Erythrocyte from the Inside Out. Annu Rev Microbiol 2013; 67:243-69. [DOI: 10.1146/annurev-micro-092412-155730] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Justin A. Boddey
- Division of Infection and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; ,
| | - Alan F. Cowman
- Division of Infection and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; ,
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250
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Matz JM, Matuschewski K, Kooij TW. Two putative protein export regulators promote Plasmodium blood stage development in vivo. Mol Biochem Parasitol 2013; 191:44-52. [DOI: 10.1016/j.molbiopara.2013.09.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/13/2013] [Accepted: 09/16/2013] [Indexed: 11/17/2022]
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