1
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Mahanta PJ, Lhouvum K. Plasmodium falciparum proteases as new drug targets with special focus on metalloproteases. Mol Biochem Parasitol 2024; 258:111617. [PMID: 38554736 DOI: 10.1016/j.molbiopara.2024.111617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/15/2024] [Accepted: 03/10/2024] [Indexed: 04/02/2024]
Abstract
Malaria poses a significant global health threat particularly due to the prevalence of Plasmodium falciparum infection. With the emergence of parasite resistance to existing drugs including the recently discovered artemisinin, ongoing research seeks novel therapeutic avenues within the malaria parasite. Proteases are promising drug targets due to their essential roles in parasite biology, including hemoglobin digestion, merozoite invasion, and egress. While exploring the genomic landscape of Plasmodium falciparum, it has been revealed that there are 92 predicted proteases, with only approximately 14 of them having been characterized. These proteases are further distributed among 26 families grouped into five clans: aspartic proteases, cysteine proteases, metalloproteases, serine proteases, and threonine proteases. Focus on metalloprotease class shows further role in organelle processing for mitochondria and apicoplasts suggesting the potential of metalloproteases as viable drug targets. Holistic understanding of the parasite intricate life cycle and identification of potential drug targets are essential for developing effective therapeutic strategies against malaria and mitigating its devastating global impact.
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Affiliation(s)
| | - Kimjolly Lhouvum
- Department of Biotechnology, National Institute of Technology, Arunachal Pradesh, India.
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2
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Nayeri T, Sarvi S, Daryani A. Effective factors in the pathogenesis of Toxoplasmagondii. Heliyon 2024; 10:e31558. [PMID: 38818168 PMCID: PMC11137575 DOI: 10.1016/j.heliyon.2024.e31558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 05/11/2024] [Accepted: 05/17/2024] [Indexed: 06/01/2024] Open
Abstract
Toxoplasma gondii (T. gondii) is a cosmopolitan protozoan parasite in humans and animals. It infects about 30 % of the human population worldwide and causes potentially fatal diseases in immunocompromised hosts and neonates. For this study, five English-language databases (ScienceDirect, ProQuest, Web of Science, PubMed, and Scopus) and the internet search engine Google Scholar were searched. This review was accomplished to draw a global perspective of what is known about the pathogenesis of T. gondii and various factors affecting it. Virulence and immune responses can influence the mechanisms of parasite pathogenesis and these factors are in turn influenced by other factors. In addition to the host's genetic background, the type of Toxoplasma strain, the routes of transmission of infection, the number of passages, and different phases of parasite life affect virulence. The identification of virulence factors of the parasite could provide promising insights into the pathogenesis of this parasite. The results of this study can be an incentive to conduct more intensive research to design and develop new anti-Toxoplasma agents (drugs and vaccines) to treat or prevent this infection. In addition, further studies are needed to better understand the key agents in the pathogenesis of T. gondii.
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Affiliation(s)
- Tooran Nayeri
- Infectious and Tropical Diseases Research Center, Dezful University of Medical Sciences, Dezful, Iran
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Shahabeddin Sarvi
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmad Daryani
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
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3
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Ahmed MA, Zaidi RH, Deshmukh GY, Saif A, Alshahrani MA, Salam SS, Elfaki MMA, Han JH, Patgiri SJ, Quan FS. Genetic Diversity and Population Genetic Structure Analysis of Plasmodium knowlesi Thrombospondin-Related Apical Merozoite Protein (TRAMP) in Clinical Samples. Genes (Basel) 2022; 13:1944. [PMID: 36360181 PMCID: PMC9689803 DOI: 10.3390/genes13111944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 10/12/2022] [Accepted: 10/19/2022] [Indexed: 08/20/2023] Open
Abstract
The simian malaria parasite Plasmodium knowlesi causes a high number of zoonotic infections in Malaysia. The thrombospondin-related apical merozoite protein (TRAMP) is an essential ligand for binding to the erythrocyte cell surface, whereby it facilitates the invasion. This study is the first attempt to determine the genetic diversity, phylogeography, natural selection and population structure from 97 full-length PkTRAMP gene sequences originating from Malaysia. We found low levels of nucleotide diversity (π~0.0065) for the full-length gene despite samples originating from geographically separated regions (i.e., Peninsular Malaysia and Malaysian Borneo). The rate of synonymous substitutions was significantly higher than that of non-synonymous substitutions, indicating a purifying selection for the full-length gene within the clinical samples. The population genetic analysis revealed that the parasite population is undergoing a significant population expansion. The analysis of the amino acid sequence alignment of 97 PkTRAMP sequences identified 15 haplotypes, of which a major shared haplotype was noted Hap 1 (n = 68, Sarawak; n = 34, Sabah; n = 12, Peninsular Malaysia; n = 22). The phylogenetic analysis using DNA sequences identified two clusters that separated due to geographical distance and three mixed clusters with samples from both Peninsular Malaysia and Malaysian Borneo. Population structure analyses indicated two distinct sub-populations (K = 2). Our findings point to the potential for independent parasite evolution, which could make zoonotic malaria control and elimination even more challenging.
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Affiliation(s)
- Md Atique Ahmed
- ICMR-Regional Medical Research Centre, NER, Dibrugarh, Assam, Bhubaneswar 786010, India
| | - Rehan Haider Zaidi
- Department of Biotechnology and Microbiology, National College, Tiruchirapalli 620001, India
| | | | - Ahmed Saif
- Department of Clinical Laboratory Sciences, Faculty of Applied Medical Sciences, Najran University, Narjan 55461, Saudi Arabia
| | - Mohammed Abdulrahman Alshahrani
- Department of Clinical Laboratory Sciences, Faculty of Applied Medical Sciences, Najran University, Narjan 55461, Saudi Arabia
| | - Syeda Sabiha Salam
- Department of Life Sciences, Dibrugarh University, Assam, Dibrugarh 786004, India
| | | | - Jin-Hee Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea
| | - Saurav Jyoti Patgiri
- ICMR-Regional Medical Research Centre, NER, Dibrugarh, Assam, Bhubaneswar 786010, India
| | - Fu-Shi Quan
- Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Graduate School, Kyung Hee University, Seoul 02447, Korea
- Department of Medical Zoology, School of Medicine, Kyung Hee University, Seoul 02447, Korea
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4
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Collins CR, Hackett F, Howell SA, Snijders AP, Russell MRG, Collinson LM, Blackman MJ. The malaria parasite sheddase SUB2 governs host red blood cell membrane sealing at invasion. eLife 2020; 9:e61121. [PMID: 33287958 PMCID: PMC7723409 DOI: 10.7554/elife.61121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 10/26/2020] [Indexed: 12/26/2022] Open
Abstract
Red blood cell (RBC) invasion by malaria merozoites involves formation of a parasitophorous vacuole into which the parasite moves. The vacuole membrane seals and pinches off behind the parasite through an unknown mechanism, enclosing the parasite within the RBC. During invasion, several parasite surface proteins are shed by a membrane-bound protease called SUB2. Here we show that genetic depletion of SUB2 abolishes shedding of a range of parasite proteins, identifying previously unrecognized SUB2 substrates. Interaction of SUB2-null merozoites with RBCs leads to either abortive invasion with rapid RBC lysis, or successful entry but developmental arrest. Selective failure to shed the most abundant SUB2 substrate, MSP1, reduces intracellular replication, whilst conditional ablation of the substrate AMA1 produces host RBC lysis. We conclude that SUB2 activity is critical for host RBC membrane sealing following parasite internalisation and for correct functioning of merozoite surface proteins.
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Affiliation(s)
- Christine R Collins
- Malaria Biochemistry Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Fiona Hackett
- Malaria Biochemistry Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Steven A Howell
- Protein Analysis and Proteomics Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Ambrosius P Snijders
- Protein Analysis and Proteomics Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Matthew RG Russell
- Electron Microscopy Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Lucy M Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Michael J Blackman
- Malaria Biochemistry Laboratory, The Francis Crick InstituteLondonUnited Kingdom
- Faculty of Infectious Diseases, London School of Hygiene & Tropical MedicineLondonUnited Kingdom
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5
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Knuepfer E, Wright KE, Kumar Prajapati S, Rawlinson TA, Mohring F, Koch M, Lyth OR, Howell SA, Villasis E, Snijders AP, Moon RW, Draper SJ, Rosanas-Urgell A, Higgins MK, Baum J, Holder AA. Divergent roles for the RH5 complex components, CyRPA and RIPR in human-infective malaria parasites. PLoS Pathog 2019; 15:e1007809. [PMID: 31185066 PMCID: PMC6588255 DOI: 10.1371/journal.ppat.1007809] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 06/21/2019] [Accepted: 05/01/2019] [Indexed: 12/26/2022] Open
Abstract
Malaria is caused by Plasmodium parasites, which invade and replicate in erythrocytes. For Plasmodium falciparum, the major cause of severe malaria in humans, a heterotrimeric complex comprised of the secreted parasite proteins, PfCyRPA, PfRIPR and PfRH5 is essential for erythrocyte invasion, mediated by the interaction between PfRH5 and erythrocyte receptor basigin (BSG). However, whilst CyRPA and RIPR are present in most Plasmodium species, RH5 is found only in the small Laverania subgenus. Existence of a complex analogous to PfRH5-PfCyRPA-PfRIPR targeting BSG, and involvement of CyRPA and RIPR in invasion, however, has not been addressed in non-Laverania parasites. Here, we establish that unlike P. falciparum, P. knowlesi and P. vivax do not universally require BSG as a host cell invasion receptor. Although we show that both PkCyRPA and PkRIPR are essential for successful invasion of erythrocytes by P. knowlesi parasites in vitro, neither protein forms a complex with each other or with an RH5-like molecule. Instead, PkRIPR is part of a different trimeric protein complex whereas PkCyRPA appears to function without other parasite binding partners. It therefore appears that in the absence of RH5, outside of the Laverania subgenus, RIPR and CyRPA have different, independent functions crucial for parasite survival. Malaria is one of the most devastating infectious diseases, causing significant human suffering and death. It is caused by parasites of the genus Plasmodium proliferating in the bloodstream. Understanding the mechanism of erythrocyte invasion is key for developing novel intervention strategies. P. falciparum, the cause of the most severe form of malaria, requires the interaction of a trimeric protein complex RH5-CyRPA-RIPR with the host receptor BSG for successful invasion. We show here that the BSG receptor is not essential for invasion by two other major causes of human malaria, P. vivax and P. knowlesi. Furthermore, we analyzed the role of CyRPA and RIPR in the absence of an RH5-like molecule in P. knowlesi and show that these molecules do not associate to form a protein complex unlike in the presence of RH5 in P. falciparum. PkRIPR is part of a different protein complex. Despite this difference CyRPA and RIPR still have essential functions during host cell invasion in other important human malaria-causing parasites.
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Affiliation(s)
- Ellen Knuepfer
- Malaria Parasitology Laboratory, The Francis Crick Institute, London, United Kingdom
- * E-mail: (EK); (KEW); (JB); (AAH)
| | - Katherine E. Wright
- Department of Life Sciences, Imperial College London, London, United Kingdom
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail: (EK); (KEW); (JB); (AAH)
| | | | | | - Franziska Mohring
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Marion Koch
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Oliver R. Lyth
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Steven A. Howell
- Proteomics Science and Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Elizabeth Villasis
- Departamento de Ciencias Celulares y Moleculares, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Ambrosius P. Snijders
- Proteomics Science and Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Robert W. Moon
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Simon J. Draper
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Matthew K. Higgins
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Jake Baum
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail: (EK); (KEW); (JB); (AAH)
| | - Anthony A. Holder
- Malaria Parasitology Laboratory, The Francis Crick Institute, London, United Kingdom
- * E-mail: (EK); (KEW); (JB); (AAH)
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6
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Armistead JS, Jennison C, O'Neill MT, Lopaticki S, Liehl P, Hanson KK, Annoura T, Rajasekaran P, Erickson SM, Tonkin CJ, Khan SM, Mota MM, Boddey JA. Plasmodium falciparum
subtilisin-like ookinete protein SOPT plays an important and conserved role during ookinete infection of the Anopheles stephensi
midgut. Mol Microbiol 2018; 109:458-473. [DOI: 10.1111/mmi.13993] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Jennifer S. Armistead
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
| | - Charlie Jennison
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
| | - Matthew T. O'Neill
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
| | - Peter Liehl
- Instituto de Medicina Molecular, Faculdade de Medicina; Universidade de Lisboa; 1649-028 Lisbon Portugal
| | - Kirsten K. Hanson
- Instituto de Medicina Molecular, Faculdade de Medicina; Universidade de Lisboa; 1649-028 Lisbon Portugal
| | - Takeshi Annoura
- Leiden Malaria Research Group, Parasitology; Leiden University Medical Centre; 2333ZA Leiden the Netherlands
| | - Pravin Rajasekaran
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
| | - Sara M. Erickson
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
| | - Christopher J. Tonkin
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
| | - Shahid M. Khan
- Leiden Malaria Research Group, Parasitology; Leiden University Medical Centre; 2333ZA Leiden the Netherlands
| | - Maria M. Mota
- Instituto de Medicina Molecular, Faculdade de Medicina; Universidade de Lisboa; 1649-028 Lisbon Portugal
| | - Justin A. Boddey
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
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7
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Glushakova S, Busse BL, Garten M, Beck JR, Fairhurst RM, Goldberg DE, Zimmerberg J. Exploitation of a newly-identified entry pathway into the malaria parasite-infected erythrocyte to inhibit parasite egress. Sci Rep 2017; 7:12250. [PMID: 28947749 PMCID: PMC5612957 DOI: 10.1038/s41598-017-12258-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 09/05/2017] [Indexed: 12/20/2022] Open
Abstract
While many parasites develop within host cells to avoid antibody responses and to utilize host cytoplasmic resources, elaborate egress processes have evolved to minimize the time between escaping and invading the next cell. In human erythrocytes, malaria parasites perforate their enclosing erythrocyte membrane shortly before egress. Here, we show that these pores clearly function as an entry pathway into infected erythrocytes for compounds that inhibit parasite egress. The natural glycosaminoglycan heparin surprisingly inhibited malaria parasite egress, trapping merozoites within infected erythrocytes. Labeled heparin neither bound to nor translocated through the intact erythrocyte membrane during parasite development, but fluxed into erythrocytes at the last minute of the parasite lifecycle. This short encounter was sufficient to significantly inhibit parasite egress and dispersion. Heparin blocks egress by interacting with both the surface of intra-erythrocytic merozoites and the inner aspect of erythrocyte membranes, preventing the rupture of infected erythrocytes but not parasitophorous vacuoles, and independently interfering with merozoite disaggregation. Since this action of heparin recapitulates that of neutralizing antibodies, membrane perforation presents a brief opportunity for a new strategy to inhibit parasite egress and replication.
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Affiliation(s)
- Svetlana Glushakova
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Brad L Busse
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Matthias Garten
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Josh R Beck
- Division of Infectious Diseases, Department of Medicine, Washington University, St. Louis, MO, 63110, USA
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases; National Institutes of Health, Bethesda, MD, 20892, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Department of Medicine, Washington University, St. Louis, MO, 63110, USA
| | - Joshua Zimmerberg
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA.
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8
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Deu E. Proteases as antimalarial targets: strategies for genetic, chemical, and therapeutic validation. FEBS J 2017; 284:2604-2628. [PMID: 28599096 PMCID: PMC5575534 DOI: 10.1111/febs.14130] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 04/29/2017] [Accepted: 06/06/2017] [Indexed: 01/17/2023]
Abstract
Malaria is a devastating parasitic disease affecting half of the world's population. The rapid emergence of resistance against new antimalarial drugs, including artemisinin-based therapies, has made the development of drugs with novel mechanisms of action extremely urgent. Proteases are enzymes proven to be well suited for target-based drug development due to our knowledge of their enzymatic mechanisms and active site structures. More importantly, Plasmodium proteases have been shown to be involved in a variety of pathways that are essential for parasite survival. However, pharmacological rather than target-based approaches have dominated the field of antimalarial drug development, in part due to the challenge of robustly validating Plasmodium targets at the genetic level. Fortunately, over the last few years there has been significant progress in the development of efficient genetic methods to modify the parasite, including several conditional approaches. This progress is finally allowing us not only to validate essential genes genetically, but also to study their molecular functions. In this review, I present our current understanding of the biological role proteases play in the malaria parasite life cycle. I also discuss how the recent advances in Plasmodium genetics, the improvement of protease-oriented chemical biology approaches, and the development of malaria-focused pharmacological assays, can be combined to achieve a robust biological, chemical and therapeutic validation of Plasmodium proteases as viable drug targets.
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Affiliation(s)
- Edgar Deu
- Chemical Biology Approaches to Malaria LaboratoryThe Francis Crick InstituteLondonUK
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9
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Plasmodium berghei PIMMS2 Promotes Ookinete Invasion of the Anopheles gambiae Mosquito Midgut. Infect Immun 2017; 85:IAI.00139-17. [PMID: 28559405 PMCID: PMC5520436 DOI: 10.1128/iai.00139-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/11/2017] [Indexed: 12/21/2022] Open
Abstract
Mosquito midgut stages of the malaria parasite present an attractive biological system to study host-parasite interactions and develop interventions to block disease transmission. Mosquito infection ensues upon oocyst development that follows ookinete invasion and traversal of the mosquito midgut epithelium. Here, we report the characterization of PIMMS2 (Plasmodium invasion of mosquito midgut screen candidate 2), a Plasmodium berghei protein with structural similarities to subtilisin-like proteins. PIMMS2 orthologs are present in the genomes of all plasmodia and are mapped between the subtilisin-encoding genes SUB1 and SUB3. P. berghei PIMMS2 is specifically expressed in zygotes and ookinetes and is localized on the ookinete surface. Loss of PIMMS2 function through gene disruption by homologous recombination leads to normal development of motile ookinetes that exhibit a severely impaired capacity to traverse the mosquito midgut and transform to oocysts. Genetic complementation of the disrupted locus with a mutated PIMMS2 allele reveals that amino acid residues corresponding to the putative subtilisin-like catalytic triad are important but not essential for protein function. Our data demonstrate that PIMMS2 is a novel ookinete-specific protein that promotes parasite traversal of the mosquito midgut epithelium and establishment of mosquito infection.
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10
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Videvall E, Cornwallis CK, Ahrén D, Palinauskas V, Valkiūnas G, Hellgren O. The transcriptome of the avian malaria parasite Plasmodium ashfordi
displays host-specific gene expression. Mol Ecol 2017; 26:2939-2958. [DOI: 10.1111/mec.14085] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 01/16/2017] [Accepted: 02/17/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Elin Videvall
- Department of Biology; Lund University; Sölvegatan 37 SE-22362 Lund Sweden
| | | | - Dag Ahrén
- Department of Biology; Lund University; Sölvegatan 37 SE-22362 Lund Sweden
- National Bioinformatics Infrastructure Sweden (NBIS); Lund University; Sölvegatan 37 SE-22362 Lund Sweden
| | - Vaidas Palinauskas
- Institute of Ecology; Nature Research Centre; Akademijos 2 LT-08412 Vilnius Lithuania
| | - Gediminas Valkiūnas
- Institute of Ecology; Nature Research Centre; Akademijos 2 LT-08412 Vilnius Lithuania
| | - Olof Hellgren
- Department of Biology; Lund University; Sölvegatan 37 SE-22362 Lund Sweden
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11
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Suárez-Cortés P, Sharma V, Bertuccini L, Costa G, Bannerman NL, Sannella AR, Williamson K, Klemba M, Levashina EA, Lasonder E, Alano P. Comparative Proteomics and Functional Analysis Reveal a Role of Plasmodium falciparum Osmiophilic Bodies in Malaria Parasite Transmission. Mol Cell Proteomics 2016; 15:3243-3255. [PMID: 27432909 DOI: 10.1074/mcp.m116.060681] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Indexed: 11/06/2022] Open
Abstract
An essential step in the transmission of the malaria parasite to the Anopheles vector is the transformation of the mature gametocytes into gametes in the mosquito gut, where they egress from the erythrocytes and mate to produce a zygote, which matures into a motile ookinete. Osmiophilic bodies are electron dense secretory organelles of the female gametocytes which discharge their contents during gamete formation, suggestive of a role in gamete egress. Only one protein with no functional annotation, Pfg377, is described to specifically reside in osmiophilic bodies in Plasmodium falciparum Importantly, Pfg377 defective gametocytes lack osmiophilic bodies and fail to infect mosquitoes, as confirmed here with newly produced pfg377 disrupted parasites. The unique feature of Pfg377 defective gametocytes of lacking osmiophilic bodies was here exploited to perform comparative, label free, global and affinity proteomics analyses of mutant and wild type gametocytes to identify components of these organelles. Subcellular localization studies with fluorescent reporter gene fusions and specific antibodies revealed an osmiophilic body localization for four out of five candidate gene products analyzed: the proteases PfSUB2 (subtilisin 2) and PfDPAP2 (Dipeptidyl aminopeptidase 2), the ortholog of the osmiophilic body component of the rodent malaria gametocytes PbGEST and a previously nonannotated 13 kDa protein. These results establish that osmiophilic bodies and their components are dispensable or marginally contribute (PfDPAP2) to gamete egress. Instead, this work reveals a previously unsuspected role of these organelles in P. falciparum development in the mosquito vector.
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Affiliation(s)
- Pablo Suárez-Cortés
- From the ‡Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy
| | - Vikram Sharma
- §School of Biomedical and Healthcare Sciences, Plymouth University, Drake Circus, Plymouth, Devon, UK
| | - Lucia Bertuccini
- ¶Dipartimento Tecnologie e Salute, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy
| | - Giulia Costa
- ‖Department of Vector Biology, Max-Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
| | - Naa-Lamiley Bannerman
- §School of Biomedical and Healthcare Sciences, Plymouth University, Drake Circus, Plymouth, Devon, UK
| | - Anna Rosa Sannella
- From the ‡Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy
| | - Kim Williamson
- **Department of Biology, Loyola University, 1032 West Sheridan Road, Chicago, Illinois 60660
| | - Michael Klemba
- ‡‡Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061
| | - Elena A Levashina
- ‖Department of Vector Biology, Max-Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
| | - Edwin Lasonder
- §School of Biomedical and Healthcare Sciences, Plymouth University, Drake Circus, Plymouth, Devon, UK
| | - Pietro Alano
- From the ‡Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy;
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12
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Beeson JG, Drew DR, Boyle MJ, Feng G, Fowkes FJI, Richards JS. Merozoite surface proteins in red blood cell invasion, immunity and vaccines against malaria. FEMS Microbiol Rev 2016; 40:343-72. [PMID: 26833236 PMCID: PMC4852283 DOI: 10.1093/femsre/fuw001] [Citation(s) in RCA: 218] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2016] [Indexed: 01/11/2023] Open
Abstract
Malaria accounts for an enormous burden of disease globally, with Plasmodium falciparum accounting for the majority of malaria, and P. vivax being a second important cause, especially in Asia, the Americas and the Pacific. During infection with Plasmodium spp., the merozoite form of the parasite invades red blood cells and replicates inside them. It is during the blood-stage of infection that malaria disease occurs and, therefore, understanding merozoite invasion, host immune responses to merozoite surface antigens, and targeting merozoite surface proteins and invasion ligands by novel vaccines and therapeutics have been important areas of research. Merozoite invasion involves multiple interactions and events, and substantial processing of merozoite surface proteins occurs before, during and after invasion. The merozoite surface is highly complex, presenting a multitude of antigens to the immune system. This complexity has proved challenging to our efforts to understand merozoite invasion and malaria immunity, and to developing merozoite antigens as malaria vaccines. In recent years, there has been major progress in this field, and several merozoite surface proteins show strong potential as malaria vaccines. Our current knowledge on this topic is reviewed, highlighting recent advances and research priorities. The authors summarize current knowledge of merozoite surface proteins of malaria parasites; their function in invasion, processing of surface proteins before, during and after invasion, their importance as targets of immunity, and the current status of malaria vaccines that target merozoite surface proteins.
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Affiliation(s)
- James G Beeson
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Microbiology, Monash University, Clayton, Victoria, Australia Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Damien R Drew
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Michelle J Boyle
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Gaoqian Feng
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Freya J I Fowkes
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Epidemiology and Preventive Medicine, Monash University, Clayton, Victoria, Australia School of Population Health, University of Melbourne, Parkville, Victoria, Australia
| | - Jack S Richards
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Microbiology, Monash University, Clayton, Victoria, Australia Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
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Walker DM, Oghumu S, Gupta G, McGwire BS, Drew ME, Satoskar AR. Mechanisms of cellular invasion by intracellular parasites. Cell Mol Life Sci 2013; 71:1245-63. [PMID: 24221133 DOI: 10.1007/s00018-013-1491-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 10/04/2013] [Accepted: 10/07/2013] [Indexed: 12/22/2022]
Abstract
Numerous disease-causing parasites must invade host cells in order to prosper. Collectively, such pathogens are responsible for a staggering amount of human sickness and death throughout the world. Leishmaniasis, Chagas disease, toxoplasmosis, and malaria are neglected diseases and therefore are linked to socio-economical and geographical factors, affecting well-over half the world's population. Such obligate intracellular parasites have co-evolved with humans to establish a complexity of specific molecular parasite-host cell interactions, forming the basis of the parasite's cellular tropism. They make use of such interactions to invade host cells as a means to migrate through various tissues, to evade the host immune system, and to undergo intracellular replication. These cellular migration and invasion events are absolutely essential for the completion of the lifecycles of these parasites and lead to their for disease pathogenesis. This review is an overview of the molecular mechanisms of protozoan parasite invasion of host cells and discussion of therapeutic strategies, which could be developed by targeting these invasion pathways. Specifically, we focus on four species of protozoan parasites Leishmania, Trypanosoma cruzi, Plasmodium, and Toxoplasma, which are responsible for significant morbidity and mortality.
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Affiliation(s)
- Dawn M Walker
- Department of Microbial Infection and Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, 43210, USA
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Child MA, Harris PK, Collins CR, Withers-Martinez C, Yeoh S, Blackman MJ. Molecular determinants for subcellular trafficking of the malarial sheddase PfSUB2. Traffic 2013; 14:1053-64. [PMID: 23834729 DOI: 10.1111/tra.12092] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 07/04/2013] [Accepted: 07/08/2013] [Indexed: 11/29/2022]
Abstract
The malaria merozoite invades erythrocytes in the vertebrate host. Iterative rounds of asexual intraerythrocytic replication result in disease. Proteases play pivotal roles in erythrocyte invasion, but little is understood about their mode of action. The Plasmodium falciparum malaria merozoite surface sheddase, PfSUB2, is one such poorly characterized example. We have examined the molecular determinants that underlie the mechanisms by which PfSUB2 is trafficked initially to invasion-associated apical organelles (micronemes) and then across the surface of the free merozoite. We show that authentic promoter activity is important for correct localization of PfSUB2, likely requiring canonical features within the intergenic region 5' of the pfsub2 locus. We further demonstrate that trafficking of PfSUB2 beyond an early compartment in the secretory pathway requires autocatalytic protease activity. Finally, we show that the PfSUB2 transmembrane domain is required for microneme targeting, while the cytoplasmic domain is essential for surface translocation of the protease to the parasite posterior following discharge from micronemes. The interplay of pre- and post-translational regulatory elements that coordinate subcellular trafficking of PfSUB2 provides the parasite with exquisite control over enzyme-substrate interactions.
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Affiliation(s)
- Matthew A Child
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, NW7 1AA, UK; Present address: Pathology Department, Stanford University School of Medicine, CA, USA
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15
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Siddiqui FA, Dhawan S, Singh S, Singh B, Gupta P, Pandey A, Mohmmed A, Gaur D, Chitnis CE. A thrombospondin structural repeat containing rhoptry protein from Plasmodium falciparum mediates erythrocyte invasion. Cell Microbiol 2013; 15:1341-56. [PMID: 23387921 DOI: 10.1111/cmi.12118] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 11/30/2012] [Accepted: 01/18/2013] [Indexed: 12/01/2022]
Abstract
Host cell invasion by Plasmodium falciparum requires multiple molecular interactions between host receptors and parasite ligands. A family of parasite proteins, which contain the conserved thrombospondin structural repeat motif (TSR), has been implicated in receptor binding during invasion. In this study we have characterized the functional role of a TSR containing blood stage protein referred to as P. falciparum thrombospondin related apical merozoite protein (PfTRAMP). Both native and recombinant PfTRAMP bind untreated as well as neuraminidase, trypsin or chymotrypsin-treated human erythrocytes. PfTRAMP is localized in the rhoptry bulb and is secreted during invasion. Adhesion of microneme protein EBA175 with its erythrocyte receptor glycophorin A provides the signal that triggers release of PfTRAMP from the rhoptries. Rabbit antibodies raised against PfTRAMP block erythrocyte invasion by P. falciparum suggesting that PfTRAMP plays an important functional role in invasion. Combination of antibodies against PfTRAMP with antibodies against microneme protein EBA175 provides an additive inhibitory effect against invasion. These observations suggest that targeting multiple conserved parasite ligands involved in different steps of invasion may provide an effective strategy for the development of vaccines against blood stage malaria parasites.
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Affiliation(s)
- Faiza Amber Siddiqui
- Malaria Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
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Identification of a potent combination of key Plasmodium falciparum merozoite antigens that elicit strain-transcending parasite-neutralizing antibodies. Infect Immun 2012. [PMID: 23184525 DOI: 10.1128/iai.01107-12] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Blood-stage malaria vaccines that target single Plasmodium falciparum antigens involved in erythrocyte invasion have not induced optimal protection in field trials. Blood-stage malaria vaccine development has faced two major hurdles, antigenic polymorphisms and molecular redundancy, which have led to an inability to demonstrate potent, strain-transcending, invasion-inhibitory antibodies. Vaccines that target multiple invasion-related parasite proteins may inhibit erythrocyte invasion more efficiently. Our approach is to develop a receptor-blocking blood-stage vaccine against P. falciparum that targets the erythrocyte binding domains of multiple parasite adhesins, blocking their interaction with their receptors and thus inhibiting erythrocyte invasion. However, with numerous invasion ligands, the challenge is to identify combinations that elicit potent strain-transcending invasion inhibition. We evaluated the invasion-inhibitory activities of 20 different triple combinations of antibodies mixed in vitro against a diverse set of six key merozoite ligands, including the novel ligands P. falciparum apical asparagine-rich protein (PfAARP), EBA-175 (PfF2), P. falciparum reticulocyte binding-like homologous protein 1 (PfRH1), PfRH2, PfRH4, and Plasmodium thrombospondin apical merozoite protein (PTRAMP), which are localized in different apical organelles and are translocated to the merozoite surface at different time points during invasion. They bind erythrocytes with different specificities and are thus involved in distinct invasion pathways. The antibody combination of EBA-175 (PfF2), PfRH2, and PfAARP produced the most efficacious strain-transcending inhibition of erythrocyte invasion against diverse P. falciparum clones. This potent antigen combination was selected for coimmunization as a mixture that induced balanced antibody responses against each antigen and inhibited erythrocyte invasion efficiently. We have thus demonstrated a novel two-step screening approach to identify a potent antigen combination that elicits strong strain-transcending invasion inhibition, supporting its development as a receptor-blocking malaria vaccine.
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Analysis of the conformation and function of the Plasmodium falciparum merozoite proteins MTRAP and PTRAMP. EUKARYOTIC CELL 2012; 11:615-25. [PMID: 22467743 DOI: 10.1128/ec.00039-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Thrombospondin repeat (TSR)-like domains are structures involved with cell adhesion. Plasmodium falciparum proteins containing TSR domains play crucial roles in parasite development. In particular, the preerythrocytic P. falciparum circumsporozoite protein is involved in hepatocyte invasion. The importance of these domains in two other malaria proteins, the merozoite-specific thrombospondin-related anonymous protein (MTRAP) and the thrombospondin-related apical membrane protein (PTRAMP), were assessed using near-full-length recombinant proteins composed of the extracellular domains produced in Escherichia coli. MTRAP is thought to be released from invasive organelles identified as micronemes during merozoite invasion to mediate motility and host cell invasion through an interaction with aldolase, an actin binding protein involved in the moving junction. PTRAMP function remains unknown. In this study, the conformation of recombinant MTRAP (rMTRAP) appeared to be a highly extended protein (2 nm by 33 nm, width by length, respectively), whereas rPTRAMP had a less extended structure. Using an erythrocyte binding assay, rMTRAP but not rPTRAMP bound human erythrocytes; rMTRAP binding was mediated through the TSR domain. MTRAP- and in general PTRAMP-specific antibodies failed to inhibit P. falciparum development in vitro. Altogether, MTRAP is a highly extended bifunctional protein that binds to an erythrocyte receptor and the merozoite motor.
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Li H, Child MA, Bogyo M. Proteases as regulators of pathogenesis: examples from the Apicomplexa. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1824:177-85. [PMID: 21683169 PMCID: PMC3232290 DOI: 10.1016/j.bbapap.2011.06.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 06/01/2011] [Accepted: 06/02/2011] [Indexed: 11/20/2022]
Abstract
The diverse functional roles that proteases play in basic biological processes make them essential for virtually all organisms. Not surprisingly, proteolysis is also a critical process required for many aspects of pathogenesis. In particular, obligate intracellular parasites must precisely coordinate proteolytic events during their highly regulated life cycle inside multiple host cell environments. Advances in chemical, proteomic and genetic tools that can be applied to parasite biology have led to an increased understanding of the complex events centrally regulated by proteases. In this review, we outline recent advances in our knowledge of specific proteolytic enzymes in two medically relevant apicomplexan parasites: Plasmodium falciparum and Toxoplasma gondii. Efforts over the last decade have begun to provide a map of key proteotolyic events that are essential for both parasite survival and propagation inside host cells. These advances in our molecular understanding of proteolytic events involved in parasite pathogenesis provide a foundation for the validation of new networks and enzyme targets that could be exploited for therapeutic purposes. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.
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Affiliation(s)
- Hao Li
- Departments of Pathology and Microbiology and Immunology and Graduate program in Chemical and Systems Biology, Stanford University, 300 Pasteur Dr. Stanford, CA. 94305
| | - Matthew A. Child
- Departments of Pathology and Microbiology and Immunology and Graduate program in Chemical and Systems Biology, Stanford University, 300 Pasteur Dr. Stanford, CA. 94305
| | - Matthew Bogyo
- Departments of Pathology and Microbiology and Immunology and Graduate program in Chemical and Systems Biology, Stanford University, 300 Pasteur Dr. Stanford, CA. 94305
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Olivieri A, Collins CR, Hackett F, Withers-Martinez C, Marshall J, Flynn HR, Skehel JM, Blackman MJ. Juxtamembrane shedding of Plasmodium falciparum AMA1 is sequence independent and essential, and helps evade invasion-inhibitory antibodies. PLoS Pathog 2011; 7:e1002448. [PMID: 22194692 PMCID: PMC3240622 DOI: 10.1371/journal.ppat.1002448] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 11/04/2011] [Indexed: 12/16/2022] Open
Abstract
The malarial life cycle involves repeated rounds of intraerythrocytic replication interspersed by host cell rupture which releases merozoites that rapidly invade fresh erythrocytes. Apical membrane antigen-1 (AMA1) is a merozoite protein that plays a critical role in invasion. Antibodies against AMA1 prevent invasion and can protect against malaria in vivo, so AMA1 is of interest as a malaria vaccine candidate. AMA1 is efficiently shed from the invading parasite surface, predominantly through juxtamembrane cleavage by a membrane-bound protease called SUB2, but also by limited intramembrane cleavage. We have investigated the structural requirements for shedding of Plasmodium falciparum AMA1 (PfAMA1), and the consequences of its inhibition. Mutagenesis of the intramembrane cleavage site by targeted homologous recombination abolished intramembrane cleavage with no effect on parasite viability in vitro. Examination of PfSUB2-mediated shedding of episomally-expressed PfAMA1 revealed that the position of cleavage is determined primarily by its distance from the parasite membrane. Certain mutations at the PfSUB2 cleavage site block shedding, and parasites expressing these non-cleavable forms of PfAMA1 on a background of expression of the wild type gene invade and replicate normally in vitro. The non-cleavable PfAMA1 is also functional in invasion. However – in contrast to the intramembrane cleavage site - mutations that block PfSUB2-mediated shedding could not be stably introduced into the genomic pfama1 locus, indicating that some shedding of PfAMA1 by PfSUB2 is essential. Remarkably, parasites expressing shedding-resistant forms of PfAMA1 exhibit enhanced sensitivity to antibody-mediated inhibition of invasion. Drugs that inhibit PfSUB2 activity should block parasite replication and may also enhance the efficacy of vaccines based on AMA1 and other merozoite surface proteins. The malaria parasite invades red blood cells. During invasion several parasite proteins, including a vaccine candidate called PfAMA1, are clipped from the parasite surface. Most of this clipping is performed by an enzyme called PfSUB2, but some also occurs through intramembrane cleavage. The function of this shedding is unknown. We have examined the requirements for shedding of PfAMA1, and the effects of mutations that block shedding. Mutations that block intramembrane cleavage have no effect on the parasite. We then show that PfSUB2 does not recognise a specific amino acid sequence in PfAMA1, but rather cleaves it at a position determined primarily by its distance from the parasite membrane. Certain mutations at the PfSUB2 cleavage site prevent shedding, and parasites expressing non-cleavable PfAMA1 along with unmodified PfAMA1 grow normally. However, these mutations cannot be introduced into the parasite's genome, showing that some shedding by PfSUB2 is essential for parasite survival. Parasites expressing shedding-resistant mutants of PfAMA1 show enhanced sensitivity to invasion-inhibitory antibodies, suggesting that shedding of surface proteins during invasion helps the parasite to evade potentially protective antibodies. Drugs that inhibit PfSUB2 may prevent disease and enhance the efficacy of vaccines based on PfAMA1.
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Affiliation(s)
- Anna Olivieri
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Christine R. Collins
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Fiona Hackett
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | | | - Joshua Marshall
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Helen R. Flynn
- Protein Analysis and Proteomics Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms, Hertfordshire, United Kingdom
| | - J. Mark Skehel
- Protein Analysis and Proteomics Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms, Hertfordshire, United Kingdom
| | - Michael J. Blackman
- Protein Analysis and Proteomics Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms, Hertfordshire, United Kingdom
- * E-mail:
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Mongui A, Angel DI, Moreno-Perez DA, Villarreal-Gonzalez S, Almonacid H, Vanegas M, Patarroyo MA. Identification and characterization of the Plasmodium vivax thrombospondin-related apical merozoite protein. Malar J 2010; 9:283. [PMID: 20942952 PMCID: PMC3020679 DOI: 10.1186/1475-2875-9-283] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 10/13/2010] [Indexed: 12/21/2022] Open
Abstract
Background Malaria caused by Plasmodium vivax is a major public health problem worldwide that affects 70-80 million people in the Middle East, Asia, Western Pacific, South America and the Caribbean. Despite its epidemiological importance, few antigens from this parasite species have been characterized to date compared to Plasmodium falciparum, due in part to the difficulties of maintaining an in vitro culture of P. vivax. This study describes the identification of the P. falciparum thrombospondin-related apical merozoite protein homologue in P. vivax (PvTRAMP) and examines its potential to be further evaluated as vaccine candidate. Methods The gene encoding PvTRAMP was identified through an extensive search of the databases hosting the genome sequence of P. vivax. Genes adjacent to pvtramp were identified in silico to determine the degree of similarity between the protein sequences encoded by equivalent chromosomic fragments in P. falciparum and Plasmodium knowlesi. The pvtramp gene was amplified from cDNA of P. vivax schizont stages, cloned and expressed in Escherichia coli. Anti-PvTRAMP antisera was obtained by inoculating rabbits with PvTRAMP B cell epitopes produced as synthetic peptides in order to assess its recognition in parasite lysates by Western blot and in intact parasites by indirect immunofluorescence. The recognition of recombinant PvTRAMP by sera from P. vivax-infected individuals living in endemic areas was also assessed by ELISA. Results The PfTRAMP homologue in P. vivax, here denoted as PvTRAMP, is a 340-amino-acid long antigen encoded by a single exon that could have a potential role in cytoadherence, as indicated by the presence of a thrombospondin structural homology repeat (TSR) domain. According to its transcription and expression profile, PvTRAMP is initially located at the parasite's apical end and later on the parasite surface. Recombinant PvTRAMP is recognized by sera from infected patients, therefore, indicating that it is targeted by the immune system during a natural infection with P. vivax. Conclusions The results of this work support conducting further studies with PvTRAMP to evaluate its immunogenicity and protection-inducing ability in the Aotus animal model.
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Affiliation(s)
- Alvaro Mongui
- Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
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21
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Novel putative glycosylphosphatidylinositol-anchored micronemal antigen of Plasmodium falciparum that binds to erythrocytes. EUKARYOTIC CELL 2009; 8:1869-79. [PMID: 19820120 DOI: 10.1128/ec.00218-09] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have identified a new Plasmodium falciparum erythrocyte binding protein that appears to be located in the micronemes of the merozoite stage of the parasite and membrane linked through a glycosylphosphatidylinositol (GPI) anchor. The protein is designated GPI-anchored micronemal antigen (GAMA) and was identified by applying a set of selection criteria to identify previously uncharacterized merozoite proteins that may have a role in cell invasion. The protein is also present in the proteomes of the sporozoite and ookinete micronemes and is conserved throughout the genus. GAMA contains a novel domain that may be constrained by disulfide bonds and a predicted C-terminal hydrophobic sequence that is presumably replaced by the GPI. The protein is synthesized late during schizogony, processed into two fragments that are linked by a disulfide bond, and translocated to an apical location, which is probably the micronemes. In a proportion of free merozoites GAMA can also be detected on the parasite surface. Following erythrocyte invasion the bulk of the protein is shed in a soluble form, although a short C-terminal fragment may be carried into the newly invaded red blood cell. The protein was shown to bind reversibly to erythrocytes and therefore represents a new example of a host cell binding protein.
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22
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Morahan BJ, Wang L, Coppel RL. No TRAP, no invasion. Trends Parasitol 2008; 25:77-84. [PMID: 19101208 DOI: 10.1016/j.pt.2008.11.004] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 11/06/2008] [Accepted: 11/07/2008] [Indexed: 11/19/2022]
Abstract
Host-cell invasion by apicomplexan parasites is a unique process that is powered by the gliding motility motor and requires a transmembrane link between the parasite cytoskeleton and the host cell. The thrombospondin-related anonymous protein (TRAP) from Plasmodium plays such a part during sporozoite invasion by linking to actin through its cytoplasmic tail while binding to hepatocytes via its extracellular portion. In recent years, there have been major advances in the identification and characterization of TRAP-family proteins in the other invasive stages of Plasmodium as well as other Apicomplexa. This review summarizes the recent experimental data on these TRAP-family proteins, focusing on their structure and function.
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Affiliation(s)
- Belinda J Morahan
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
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23
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Ganesan K, Ponmee N, Jiang L, Fowble JW, White J, Kamchonwongpaisan S, Yuthavong Y, Wilairat P, Rathod PK. A genetically hard-wired metabolic transcriptome in Plasmodium falciparum fails to mount protective responses to lethal antifolates. PLoS Pathog 2008; 4:e1000214. [PMID: 19023412 PMCID: PMC2581438 DOI: 10.1371/journal.ppat.1000214] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 10/21/2008] [Indexed: 11/25/2022] Open
Abstract
Genome sequences of Plasmodium falciparum allow for global analysis of drug responses to antimalarial agents. It was of interest to learn how DNA microarrays may be used to study drug action in malaria parasites. In one large, tightly controlled study involving 123 microarray hybridizations between cDNA from isogenic drug-sensitive and drug-resistant parasites, a lethal antifolate (WR99210) failed to over-produce RNA for the genetically proven principal target, dihydrofolate reductase-thymidylate synthase (DHFR-TS). This transcriptional rigidity carried over to metabolically related RNA encoding folate and pyrimidine biosynthesis, as well as to the rest of the parasite genome. No genes were reproducibly up-regulated by more than 2-fold until 24 h after initial drug exposure, even though clonal viability decreased by 50% within 6 h. We predicted and showed that while the parasites do not mount protective transcriptional responses to antifolates in real time, P. falciparum cells transfected with human DHFR gene, and adapted to long-term WR99210 exposure, adjusted the hard-wired transcriptome itself to thrive in the presence of the drug. A system-wide incapacity for changing RNA levels in response to specific metabolic perturbations may contribute to selective vulnerabilities of Plasmodium falciparum to lethal antimetabolites. In addition, such regulation affects how DNA microarrays are used to understand the mode of action of antimetabolites. Traditional knowledge of gene regulation, learned largely from non-pathogenic model organisms such as E. coli, yeast, and mice, suggests that RNA for metabolic pathways are regulated in large part by DNA-binding transcriptional factors that are responsive to cellular metabolic needs. We demonstrate that the malaria-causing Plasmodium falciparum parasites, under lethal drug pressure from an antifolate with a known mechanism of action, are incapable of large reproducible changes in RNA levels for the target pathways, or for any other gene throughout the genome. Small RNA changes, possibly informative of perturbed pathways, can be detected in dying parasites. In addition, significant RNA changes are seen when the hard-wired program, governing RNA levels, itself is altered. Our data formally proves that RNA levels for intermediary metabolism in malaria parasites are largely predetermined. We propose that as a parasite with a complex life cycle travels from one largely predictable intracellular biochemical environment to another, such hard-wiring may be sufficient to manage transcript levels for intermediary metabolism without employing sensory functions. Such a system-wide host–parasite difference in gene regulation may create unexpected pharmacological opportunities when important target pathways are rigid in the parasite but dynamically regulated in host cells.
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Affiliation(s)
- Karthikeyan Ganesan
- Department of Chemistry and Global Health, University of Washington, Seattle, Washington, United States of America
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Green JL, Rees-Channer RR, Howell SA, Martin SR, Knuepfer E, Taylor HM, Grainger M, Holder AA. The motor complex of Plasmodium falciparum: phosphorylation by a calcium-dependent protein kinase. J Biol Chem 2008; 283:30980-9. [PMID: 18768477 PMCID: PMC2576532 DOI: 10.1074/jbc.m803129200] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 09/03/2008] [Indexed: 11/21/2022] Open
Abstract
Calcium-dependent protein kinases (CDPKs) of Apicomplexan parasites are crucial for the survival of the parasite throughout its life cycle. CDPK1 is expressed in the asexual blood stages of the parasite, particularly late stage schizonts. We have identified two substrates of Plasmodium falciparum CDPK1: myosin A tail domain-interacting protein (MTIP) and glideosome-associated protein 45 (GAP45), both of which are components of the motor complex that generates the force required by the parasite to actively invade host cells. Indirect immunofluorescence shows that CDPK1 localizes to the periphery of P. falciparum merozoites and is therefore suitably located to act on MTIP and GAP45 at the inner membrane complex. A proportion of both GAP45 and MTIP is phosphorylated in schizonts, and we demonstrate that both proteins can be efficiently phosphorylated by CDPK1 in vitro. A primary phosphorylation of MTIP occurs at serine 47, whereas GAP45 is phosphorylated at two sites, one of which could also be detected in phosphopeptides purified from parasite lysates. Both CDPK1 activity and host cell invasion can be inhibited by the kinase inhibitor K252a, suggesting that CDPK1 is a suitable target for antimalarial drug development.
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Affiliation(s)
- Judith L Green
- Medical Research Council National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
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Chen Z, Harb OS, Roos DS. In silico identification of specialized secretory-organelle proteins in apicomplexan parasites and in vivo validation in Toxoplasma gondii. PLoS One 2008; 3:e3611. [PMID: 18974850 PMCID: PMC2575384 DOI: 10.1371/journal.pone.0003611] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Accepted: 10/06/2008] [Indexed: 12/04/2022] Open
Abstract
Apicomplexan parasites, including the human pathogens Toxoplasma gondii and Plasmodium falciparum, employ specialized secretory organelles (micronemes, rhoptries, dense granules) to invade and survive within host cells. Because molecules secreted from these organelles function at the host/parasite interface, their identification is important for understanding invasion mechanisms, and central to the development of therapeutic strategies. Using a computational approach based on predicted functional domains, we have identified more than 600 candidate secretory organelle proteins in twelve apicomplexan parasites. Expression in transgenic T. gondii of eight proteins identified in silico confirms that all enter into the secretory pathway, and seven target to apical organelles associated with invasion. An in silico approach intended to identify possible host interacting proteins yields a dataset enriched in secretory/transmembrane proteins, including most of the antigens known to be engaged by apicomplexan parasites during infection. These domain pattern and projected interactome approaches significantly expand the repertoire of proteins that may be involved in host parasite interactions.
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Affiliation(s)
- ZhongQiang Chen
- Department of Biology, Penn Genomic Frontiers Institute, and the Graduate Program in Genomics and Computational Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Omar S. Harb
- Department of Biology, Penn Genomic Frontiers Institute, and the Graduate Program in Genomics and Computational Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (DSR); (OSH)
| | - David S. Roos
- Department of Biology, Penn Genomic Frontiers Institute, and the Graduate Program in Genomics and Computational Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (DSR); (OSH)
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26
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Rodriguez LE, Curtidor H, Urquiza M, Cifuentes G, Reyes C, Patarroyo ME. Intimate Molecular Interactions of P. falciparum Merozoite Proteins Involved in Invasion of Red Blood Cells and Their Implications for Vaccine Design. Chem Rev 2008; 108:3656-705. [DOI: 10.1021/cr068407v] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Hernando Curtidor
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
| | - Mauricio Urquiza
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
| | - Gladys Cifuentes
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
| | - Claudia Reyes
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
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27
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Arastu-Kapur S, Ponder EL, Fonović UP, Yeoh S, Yuan F, Fonović M, Grainger M, Phillips CI, Powers JC, Bogyo M. Identification of proteases that regulate erythrocyte rupture by the malaria parasite Plasmodium falciparum. Nat Chem Biol 2008; 4:203-13. [PMID: 18246061 DOI: 10.1038/nchembio.70] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 01/08/2008] [Indexed: 11/09/2022]
Abstract
Newly replicated Plasmodium falciparum parasites escape from host erythrocytes through a tightly regulated process that is mediated by multiple classes of proteolytic enzymes. However, the identification of specific proteases has been challenging. We describe here a forward chemical genetic screen using a highly focused library of more than 1,200 covalent serine and cysteine protease inhibitors to identify compounds that block host cell rupture by P. falciparum. Using hits from the library screen, we identified the subtilisin-family serine protease PfSU B1 and the cysteine protease dipeptidyl peptidase 3 (DPAP3) as primary regulators of this process. Inhibition of both DPAP3 and PfSUB1 caused a block in proteolytic processing of the serine repeat antigen (SERA) protein SERA5 that correlated with the observed block in rupture. Furthermore, DPAP3 inhibition reduced the levels of mature PfSUB1. These results suggest that two mechanistically distinct proteases function to regulate processing of downstream substrates required for efficient release of parasites from host red blood cells.
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Affiliation(s)
- Shirin Arastu-Kapur
- Department of Pathology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, USA
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28
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Dowse TJ, Koussis K, Blackman MJ, Soldati-Favre D. Roles of proteases during invasion and egress by Plasmodium and Toxoplasma. Subcell Biochem 2008; 47:121-139. [PMID: 18512347 DOI: 10.1007/978-0-387-78267-6_10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Apicomplexan pathogens replicate exclusively within the confines of a host cell. Entry into (invasion) and exit from (egress) these cells requires an array of specialized parasite molecules, many of which have long been considered to have potential as targets of drug or vaccine-based therapies. In this chapter the authors discuss the current state of knowledge regarding the role of parasite proteolytic enzymes in these critical steps in the life cycle of two clinically important apicomplexan genera, Plasmodium and Toxoplasma. At least three distinct proteases of the cysteine mechanistic class have been implicated in egress of the malaria parasite from cells of its vertebrate and insect host. In contrast, the bulk of the evidence indicates a prime role for serine proteases of the subtilisin and rhomboid families in invasion by both parasites. Whereas proteases involved in egress may function predominantly to degrade host cell structures, proteases involved in invasion probably act primarily as maturases and 'sheddases', required to activate and ultimately remove ligands involved in interactions with the host cell.
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Affiliation(s)
- Timothy J Dowse
- Department of Biological Sciences, Imperial College, London, UK
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29
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Calderón JC, Curtidor H, González O, Cifuentes G, Reyes C, Patarroyo ME. High affinity interactions between red blood cell receptors and synthetic Plasmodium thrombospondin-related apical merozoite protein (PTRAMP) peptides. Biochimie 2007; 90:802-10. [PMID: 18158923 DOI: 10.1016/j.biochi.2007.11.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Accepted: 11/30/2007] [Indexed: 11/19/2022]
Abstract
Plasmodium falciparum thrombospondin-related apical merozoite protein (PTRAMP) has a thrombospondin related (TSR) domain which in many proteins has been reported as a fragment involved in pathogen-host and cell-interactions. Receptor-ligand studies using eighteen non-overlapping 20-aminoacid-long synthetic peptides from this protein were carried out to determine regions involved in parasite invasion of red blood cells (RBC). Two high activity binding peptides (HABPs) were determined, 33405 (21YISSNDLTSTNLKVRNNWEH40) and 33413 (180LEGPIQFSLGKSSGAFRINY199), presenting high dissociation constants and positive cooperativity. One of the HABPs displayed a modified Plasmodium export element (PEXEL), suggesting that this protein could be involved in the merozoite cytoplasmic reticulum, parasitophorous vacuole, red blood cell (RBC) cytosol, and probably infected RBC (iRBC) membrane transport of some other molecules and nutrients. Enzymatic treatment of RBCs increased HABP 33405 binding to them whilst it decreased HABP 33413 binding. Merozoite invasion assays revealed that HABPs have around 57% ability to inhibit new RBC invasion. Circular dichroism revealed the presence of possible alpha-helical elements in both HABPs structures. RBC binding interaction specificity and the presence of a PEXEL motif make these 2 HABPs good candidates for being included in further studies to develop a new multi-antigenic, multi-stage, subunit-based, chemically-synthesised, anti-malarial vaccine.
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30
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Baker RP, Wijetilaka R, Urban S. Two Plasmodium rhomboid proteases preferentially cleave different adhesins implicated in all invasive stages of malaria. PLoS Pathog 2006; 2:e113. [PMID: 17040128 PMCID: PMC1599764 DOI: 10.1371/journal.ppat.0020113] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Accepted: 09/14/2006] [Indexed: 11/18/2022] Open
Abstract
Invasion of host cells by the malaria pathogen Plasmodium relies on parasite transmembrane adhesins that engage host-cell receptors. Adhesins must be released by cleavage before the parasite can enter the cell, but the processing enzymes have remained elusive. Recent work indicates that the Toxoplasma rhomboid intramembrane protease TgROM5 catalyzes this essential cleavage. However, Plasmodium does not encode a direct TgROM5 homolog. We examined processing of the 14 Plasmodium falciparum adhesins currently thought to be involved in invasion by both model and Plasmodium rhomboid proteases in a heterologous assay. While most adhesins contain aromatic transmembrane residues and could not be cleaved by nonparasite rhomboid proteins, including Drosophila Rhomboid-1, Plasmodium falciparum rhomboid protein (PfROM)4 (PFE0340c) was able to process these adhesins efficiently and displayed novel substrate specificity. Conversely, PfROM1 (PF11_0150) shared specificity with rhomboid proteases from other organisms and was the only PfROM able to cleave apical membrane antigen 1 (AMA1). PfROM 1 and/or 4 was thus able to cleave diverse adhesins including TRAP, CTRP, MTRAP, PFF0800c, EBA-175, BAEBL, JESEBL, MAEBL, AMA1, Rh1, Rh2a, Rh2b, and Rh4, but not PTRAMP, and cleavage relied on the adhesin transmembrane domains. Swapping transmembrane regions between BAEBL and AMA1 switched the relative preferences of PfROMs 1 and 4 for these two substrates. Our analysis indicates that PfROMs 1 and 4 function with different substrate specificities that together constitute the specificity of TgROM5 to cleave diverse adhesins. This is the first enzymatic analysis of Plasmodium rhomboid proteases and suggests an involvement of PfROMs in all invasive stages of the malaria lifecycle, in both the vertebrate host and the mosquito vector. Malaria is a devastating global disease that afflicts over 10% of the world's population, claiming between 1 and 3 million lives annually. Invasion of host cells by the malaria parasite Plasmodium ultimately requires enzymes to release close contacts made between the parasite and host cell, but these enzymes have not been identified. Rhomboid enzymes were previously found to be involved in this process in the related pathogen Toxoplasma. The present work examined the activity of Plasmodium rhomboid enzymes, and revealed that two Plasmodium rhomboid enzymes can cleave most, if not all, of the proteins currently known to mediate contacts between the parasite and host-cell membranes during invasion. The two rhomboid enzymes had different specificities for the different target proteins, but together could process all of the proteins that the similar Toxoplasma rhomboid enzyme could process alone. This analysis suggests that rhomboid enzymes may be essential for the ability of the parasite to invade host cells through different pathways both in the human and mosquito hosts, and therefore offers a possible new therapeutic target to explore for treating or controlling the devastating effects of malaria.
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Affiliation(s)
- Rosanna P Baker
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Center of Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Ruvini Wijetilaka
- Center of Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Sinisa Urban
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Center of Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail:
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