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Patel PN, Dickey TH, Diouf A, Salinas ND, McAleese H, Ouahes T, Long CA, Miura K, Lambert LE, Tolia NH. Structure-based design of a strain transcending AMA1-RON2L malaria vaccine. Nat Commun 2023; 14:5345. [PMID: 37660103 PMCID: PMC10475129 DOI: 10.1038/s41467-023-40878-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/14/2023] [Indexed: 09/04/2023] Open
Abstract
Apical membrane antigen 1 (AMA1) is a key malaria vaccine candidate and target of neutralizing antibodies. AMA1 binds to a loop in rhoptry neck protein 2 (RON2L) to form the moving junction during parasite invasion of host cells, and this complex is conserved among apicomplexan parasites. AMA1-RON2L complex immunization achieves higher growth inhibitory activity than AMA1 alone and protects mice against Plasmodium yoelii challenge. Here, three single-component AMA1-RON2L immunogens were designed that retain the structure of the two-component AMA1-RON2L complex: one structure-based design (SBD1) and two insertion fusions. All immunogens elicited high antibody titers with potent growth inhibitory activity, yet these antibodies did not block RON2L binding to AMA1. The SBD1 immunogen induced significantly more potent strain-transcending neutralizing antibody responses against diverse strains of Plasmodium falciparum than AMA1 or AMA1-RON2L complex vaccination. This indicates that SBD1 directs neutralizing antibody responses to strain-transcending epitopes in AMA1 that are independent of RON2L binding. This work underscores the importance of neutralization mechanisms that are distinct from RON2 blockade. The stable single-component SBD1 immunogen elicits potent strain-transcending protection that may drive the development of next-generation vaccines for improved malaria and apicomplexan parasite control.
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Affiliation(s)
- Palak N Patel
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Thayne H Dickey
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Nichole D Salinas
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Holly McAleese
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tarik Ouahes
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Lynn E Lambert
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Niraj H Tolia
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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Mukherjee S, Nguyen S, Sharma E, Goldberg DE. Maturation and substrate processing topography of the Plasmodium falciparum invasion/egress protease plasmepsin X. Nat Commun 2022; 13:4537. [PMID: 35927261 PMCID: PMC9352755 DOI: 10.1038/s41467-022-32271-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 07/22/2022] [Indexed: 11/08/2022] Open
Abstract
The malaria parasite Plasmodium invades a host erythrocyte, multiplies within a parasitophorous vacuole (PV) and then ruptures the PV and erythrocyte membranes in a process known as egress. Both egress and invasion are controlled by effector proteins discharged from specialized secretory organelles. The aspartic protease plasmepsin X (PM X) regulates activity for many of these effectors, but it is unclear how PM X accesses its diverse substrates that reside in different organelles. PM X also autoprocesses to generate different isoforms. The function of this processing is not understood. We have mapped the self-cleavage sites and have constructed parasites with cleavage site mutations. Surprisingly, a quadruple mutant that remains full-length retains in vitro activity, is trafficked normally, and supports normal egress, invasion and parasite growth. The N-terminal half of the prodomain stays bound to the catalytic domain even after processing and is required for proper intracellular trafficking of PM X. We find that this enzyme cleaves microneme and exoneme substrates before discharge, while the rhoptry substrates that are dependent on PM X activity are cleaved after exoneme discharge into the PV. The data give insight into the temporal, spatial and biochemical control of this unusual but important aspartic protease.
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Affiliation(s)
- Sumit Mukherjee
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Suong Nguyen
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Eashan Sharma
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.
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3
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Abugri J, Ayariga J, Sunwiale SS, Wezena CA, Gyamfi JA, Adu-Frimpong M, Agongo G, Dongdem JT, Abugri D, Dinko B. Targeting the Plasmodium falciparum proteome and organelles for potential antimalarial drug candidates. Heliyon 2022; 8:e10390. [PMID: 36033316 PMCID: PMC9398786 DOI: 10.1016/j.heliyon.2022.e10390] [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: 09/12/2021] [Revised: 01/12/2022] [Accepted: 08/15/2022] [Indexed: 11/28/2022] Open
Abstract
There is an unmet need to unearth alternative treatment options for malaria, wherein this quest is more pressing in recent times due to high morbidity and mortality data arising mostly from the endemic countries coupled with partial diversion of attention from the disease in view of the SARS-Cov-2 pandemic. Available therapeutic options for malaria have been severely threatened with the emergence of resistance to almost all the antimalarial drugs by the Plasmodium falciparum parasite in humans, which is a worrying situation. Artemisinin combination therapies (ACT) that have so far been the mainstay of malaria have encountered resistance by malaria parasite in South East Asia, which is regarded as a notorious ground zero for the emergence of resistance to antimalarial drugs. This review analyzes a few key druggable targets for the parasite and the potential of specific inhibitors to mitigate the emerging antimalarial drug resistance problem by providing a concise assessment of the essential proteins of the malaria parasite that could serve as targets. Moreover, this work provides a summary of the advances made in malaria parasite biology and the potential to leverage these findings for antimalarial drug production.
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Affiliation(s)
- James Abugri
- Department of Biochemistry and Forensic Sciences, School of Chemical and Biochemical Sciences, C. K. Tedam University of Technology and Applied Sciences (CKT-UTAS), Navrongo, Ghana
| | - Joseph Ayariga
- The Biomedical Engineering Programme, Alabama State University, Montgomery, AL, 36104, USA
| | - Samuel Sunyazi Sunwiale
- Department of Biochemistry and Forensic Sciences, School of Chemical and Biochemical Sciences, C. K. Tedam University of Technology and Applied Sciences (CKT-UTAS), Navrongo, Ghana
| | - Cletus Adiyaga Wezena
- Department of Microbiology, School of Biosciences, University for Development Studies (UDS), Nyankpala Campus, Tamale, Ghana
| | - Julien Agyemang Gyamfi
- Department of Biochemistry and Forensic Sciences, School of Chemical and Biochemical Sciences, C. K. Tedam University of Technology and Applied Sciences (CKT-UTAS), Navrongo, Ghana
| | - Michael Adu-Frimpong
- Department of Biochemistry and Forensic Sciences, School of Chemical and Biochemical Sciences, C. K. Tedam University of Technology and Applied Sciences (CKT-UTAS), Navrongo, Ghana
| | - Godfred Agongo
- Department of Biochemistry and Forensic Sciences, School of Chemical and Biochemical Sciences, C. K. Tedam University of Technology and Applied Sciences (CKT-UTAS), Navrongo, Ghana
| | - Julius Tieroyaare Dongdem
- Department of Biochemistry and Molecular Medicine. School of Medicine. University for Development Studies (UDS), Tamale-Campus, Ghana
| | - Daniel Abugri
- Department of Biological Sciences, Microbiology PhD Programme, Laboratory of Ethnomedicine, Parasitology, and Drug Discovery, College of Science, Technology, Engineering and Mathematics, Alabama State University, Montgomery, USA
| | - Bismarck Dinko
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho. Ghana
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4
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Paone S, D'Alessandro S, Parapini S, Celani F, Tirelli V, Pourshaban M, Olivieri A. Characterization of the erythrocyte GTPase Rac1 in relation to Plasmodium falciparum invasion. Sci Rep 2020; 10:22054. [PMID: 33328606 PMCID: PMC7744522 DOI: 10.1038/s41598-020-79052-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 11/30/2020] [Indexed: 12/01/2022] Open
Abstract
Malaria is still a devastating disease with 228 million cases globally and 405,000 lethal outcomes in 2018, mainly in children under five years of age. The threat of emerging malaria strains resistant to currently available drugs has made the search for novel drug targets compelling. The process by which Plasmodium falciparum parasites invade the host cell has been widely studied, but only a few erythrocyte proteins involved in this process have been identified so far. The erythrocyte protein Rac1 is a GTPase that plays an important role in host cell invasion by many intracellular pathogens. Here we show that Rac1 is recruited in proximity to the site of parasite entry during P. falciparum invasion process and that subsequently localizes to the parasitophorous vacuole membrane. We also suggest that this GTPase may be involved in erythrocyte invasion by P. falciparum, by testing the effect of specific Rac1 inhibitory compounds. Finally, we suggest a secondary role of the erythrocyte GTPase also in parasite intracellular development. We here characterize a new erythrocyte protein potentially involved in P. falciparum invasion of the host cell and propose the human GTPase Rac1 as a novel and promising antimalarial drug target.
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Affiliation(s)
- Silvio Paone
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy.,Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza University of Rome, Rome, Italy
| | - Sarah D'Alessandro
- Dipartimento di Scienze Biomediche, Chirurgiche e Odontoiatriche, University of Milan, Milan, Italy
| | - Silvia Parapini
- Dipartimento di Scienze Biomediche Per La Salute, University of Milan, Milan, Italy
| | - Francesco Celani
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
| | - Valentina Tirelli
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
| | | | - Anna Olivieri
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy.
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5
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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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6
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Favuzza P, de Lera Ruiz M, Thompson JK, Triglia T, Ngo A, Steel RWJ, Vavrek M, Christensen J, Healer J, Boyce C, Guo Z, Hu M, Khan T, Murgolo N, Zhao L, Penington JS, Reaksudsan K, Jarman K, Dietrich MH, Richardson L, Guo KY, Lopaticki S, Tham WH, Rottmann M, Papenfuss T, Robbins JA, Boddey JA, Sleebs BE, Sabroux HJ, McCauley JA, Olsen DB, Cowman AF. Dual Plasmepsin-Targeting Antimalarial Agents Disrupt Multiple Stages of the Malaria Parasite Life Cycle. Cell Host Microbe 2020; 27:642-658.e12. [PMID: 32109369 PMCID: PMC7146544 DOI: 10.1016/j.chom.2020.02.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/22/2019] [Accepted: 02/11/2020] [Indexed: 01/07/2023]
Abstract
Artemisin combination therapy (ACT) is the main treatment option for malaria, which is caused by the intracellular parasite Plasmodium. However, increased resistance to ACT highlights the importance of finding new drugs. Recently, the aspartic proteases Plasmepsin IX and X (PMIX and PMX) were identified as promising drug targets. In this study, we describe dual inhibitors of PMIX and PMX, including WM382, that block multiple stages of the Plasmodium life cycle. We demonstrate that PMX is a master modulator of merozoite invasion and direct maturation of proteins required for invasion, parasite development, and egress. Oral administration of WM382 cured mice of P. berghei and prevented blood infection from the liver. In addition, WM382 was efficacious against P. falciparum asexual infection in humanized mice and prevented transmission to mosquitoes. Selection of resistant P. falciparum in vitro was not achievable. Together, these show that dual PMIX and PMX inhibitors are promising candidates for malaria treatment and prevention.
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Affiliation(s)
- Paola Favuzza
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Jennifer K Thompson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Tony Triglia
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Anna Ngo
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Ryan W J Steel
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Marissa Vavrek
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Janni Christensen
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Julie Healer
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Zhuyan Guo
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Mengwei Hu
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Tanweer Khan
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Nicholas Murgolo
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Lianyun Zhao
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | | | - Kitsanapong Reaksudsan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Kate Jarman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Melanie H Dietrich
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Lachlan Richardson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Kai-Yuan Guo
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Wai-Hong Tham
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Tony Papenfuss
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Justin A Boddey
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Hélène Jousset Sabroux
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - John A McCauley
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - David B Olsen
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA.
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia.
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7
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Pace T, Grasso F, Camarda G, Suarez C, Blackman MJ, Ponzi M, Olivieri A. The Plasmodium berghei serine protease PbSUB1 plays an important role in male gamete egress. Cell Microbiol 2019; 21:e13028. [PMID: 30941868 PMCID: PMC6766862 DOI: 10.1111/cmi.13028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 03/07/2019] [Accepted: 03/28/2019] [Indexed: 01/10/2023]
Abstract
The Plasmodium subtilisin-like serine protease SUB1 is expressed in hepatic and both asexual and sexual blood parasite stages. SUB1 is required for egress of invasive forms of the parasite from both erythrocytes and hepatocytes, but its subcellular localisation, function, and potential substrates in the sexual stages are unknown. Here, we have characterised the expression profile and subcellular localisation of SUB1 in Plasmodium berghei sexual stages. We show that the protease is selectively expressed in mature male gametocytes and localises to secretory organelles known to be involved in gamete egress, called male osmiophilic bodies. We have investigated PbSUB1 function in the sexual stages by generating P. berghei transgenic lines deficient in PbSUB1 expression or enzyme activity in gametocytes. Our results demonstrate that PbSUB1 plays a role in male gamete egress. We also show for the first time that the PbSUB1 substrate PbSERA3 is expressed in gametocytes and processed by PbSUB1 upon gametocyte activation. Taken together, our results strongly suggest that PbSUB1 is not only a promising drug target for asexual stages but could also be an attractive malaria transmission-blocking target.
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Affiliation(s)
- Tomasino Pace
- Dipartimento di Malattie InfettiveIstituto Superiore di SanitàRomeItaly
| | - Felicia Grasso
- Dipartimento di Malattie InfettiveIstituto Superiore di SanitàRomeItaly
| | - Grazia Camarda
- Dipartimento di Malattie InfettiveIstituto Superiore di SanitàRomeItaly
| | - Catherine Suarez
- Malaria Biochemistry LaboratoryThe Francis Crick InstituteLondonUK
| | - Michael J. Blackman
- Malaria Biochemistry LaboratoryThe Francis Crick InstituteLondonUK
- Faculty of Infectious and Tropical DiseasesLondon School of Hygiene and Tropical MedicineLondonUK
| | - Marta Ponzi
- Dipartimento di Malattie InfettiveIstituto Superiore di SanitàRomeItaly
| | - Anna Olivieri
- Dipartimento di Malattie InfettiveIstituto Superiore di SanitàRomeItaly
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8
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Patel A, Perrin AJ, Flynn HR, Bisson C, Withers-Martinez C, Treeck M, Flueck C, Nicastro G, Martin SR, Ramos A, Gilberger TW, Snijders AP, Blackman MJ, Baker DA. Cyclic AMP signalling controls key components of malaria parasite host cell invasion machinery. PLoS Biol 2019; 17:e3000264. [PMID: 31075098 PMCID: PMC6530879 DOI: 10.1371/journal.pbio.3000264] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 05/22/2019] [Accepted: 04/26/2019] [Indexed: 01/01/2023] Open
Abstract
Cyclic AMP (cAMP) is an important signalling molecule across evolution, but its role in malaria parasites is poorly understood. We have investigated the role of cAMP in asexual blood stage development of Plasmodium falciparum through conditional disruption of adenylyl cyclase beta (ACβ) and its downstream effector, cAMP-dependent protein kinase (PKA). We show that both production of cAMP and activity of PKA are critical for erythrocyte invasion, whilst key developmental steps that precede invasion still take place in the absence of cAMP-dependent signalling. We also show that another parasite protein with putative cyclic nucleotide binding sites, Plasmodium falciparum EPAC (PfEpac), does not play an essential role in blood stages. We identify and quantify numerous sites, phosphorylation of which is dependent on cAMP signalling, and we provide mechanistic insight as to how cAMP-dependent phosphorylation of the cytoplasmic domain of the essential invasion adhesin apical membrane antigen 1 (AMA1) regulates erythrocyte invasion.
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Affiliation(s)
- Avnish Patel
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Abigail J. Perrin
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Helen R. Flynn
- Mass Spectrometry Proteomics Platform, The Francis Crick Institute, London, United Kingdom
| | - Claudine Bisson
- Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, London, United Kingdom
| | | | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Christian Flueck
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Giuseppe Nicastro
- Macromolecular Structure Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Stephen R. Martin
- Macromolecular Structure Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Andres Ramos
- Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Tim W. Gilberger
- Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ambrosius P. Snijders
- Mass Spectrometry Proteomics Platform, The Francis Crick Institute, London, United Kingdom
| | - Michael J. Blackman
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - David A. Baker
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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9
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Das S, Lemgruber L, Tay CL, Baum J, Meissner M. Multiple essential functions of Plasmodium falciparum actin-1 during malaria blood-stage development. BMC Biol 2017; 15:70. [PMID: 28810863 PMCID: PMC5557482 DOI: 10.1186/s12915-017-0406-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/14/2017] [Indexed: 01/04/2023] Open
Abstract
Background The phylum Apicomplexa includes intracellular parasites causing immense global disease burden, the deadliest of them being the human malaria parasite Plasmodium falciparum, which invades and replicates within erythrocytes. The cytoskeletal protein actin is well conserved within apicomplexans but divergent from mammalian actins, and was primarily reported to function during host cell invasion. However, novel invasion mechanisms have been described for several apicomplexans, and specific functions of the acto-myosin system are being reinvestigated. Of the two actin genes in P. falciparum, actin-1 (pfact1) is ubiquitously expressed in all life-cycle stages and is thought to be required for erythrocyte invasion, although its functions during parasite development are unknown, and definitive in vivo characterisation during invasion is lacking. Results Here we have used a conditional Cre-lox system to investigate the functions of PfACT1 during P. falciparum blood-stage development and host cell invasion. We demonstrate that PfACT1 is crucially required for segregation of the plastid-like organelle, the apicoplast, and for efficient daughter cell separation during the final stages of cytokinesis. Surprisingly, we observe that egress from the host cell is not an actin-dependent process. Finally, we show that parasites lacking PfACT1 are capable of microneme secretion, attachment and formation of a junction with the erythrocyte, but are incapable of host cell invasion. Conclusions This study provides important mechanistic insights into the definitive essential functions of PfACT1 in P. falciparum, which are not only of biological interest, but owing to functional divergence from mammalian actins, could also form the basis for the development of novel therapeutics against apicomplexans. Electronic supplementary material The online version of this article (doi:10.1186/s12915-017-0406-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sujaan Das
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK.
| | - Leandro Lemgruber
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Chwen L Tay
- Department of Life Sciences, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Jake Baum
- Department of Life Sciences, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Markus Meissner
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK. .,Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Munich, Germany.
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10
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Purification and antiparasitic activity of a few legume serine proteinase inhibitors: Effect on erythrocyte invasion, schizont rupture and proteolytic processing of the Plasmodium falciparum AMA1 protein. Process Biochem 2017. [DOI: 10.1016/j.procbio.2017.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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11
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Dogga SK, Soldati-Favre D. Biology of rhomboid proteases in infectious diseases. Semin Cell Dev Biol 2016; 60:38-45. [PMID: 27567708 DOI: 10.1016/j.semcdb.2016.08.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/04/2016] [Accepted: 08/23/2016] [Indexed: 12/26/2022]
Abstract
Rhomboids are a well-conserved class of intramembrane serine proteases found in all kingdoms of life, sharing a conserved core structure of at least six transmembrane (TM) domains that contain the catalytic serine-histidine dyad. The rhomboid proteases, which cleave membrane embedded substrates within their TM domains, are emerging as an important group of enzymes controlling a myriad of biological processes. These enzymes are found in a wide variety of pathogens manifesting important roles in their pathological processes. Accordingly, they have received considerable attention as potential targets for pharmacological intervention over the past few years. This review provides a general update on rhomboid proteases and their roles in pathogenesis of human infectious agents.
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Affiliation(s)
- Sunil Kumar Dogga
- Department of Microbiology and Molecular Medicine, University of Geneva, CMU, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland.
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva, CMU, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland
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12
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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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13
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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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14
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Kim JJ, Flueck C, Franz E, Sanabria-Figueroa E, Thompson E, Lorenz R, Bertinetti D, Baker DA, Herberg FW, Kim C. Crystal structures of the carboxyl cGMP binding domain of the Plasmodium falciparum cGMP-dependent protein kinase reveal a novel capping triad crucial for merozoite egress. PLoS Pathog 2015; 11:e1004639. [PMID: 25646845 PMCID: PMC4412288 DOI: 10.1371/journal.ppat.1004639] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 12/20/2014] [Indexed: 01/05/2023] Open
Abstract
The Plasmodium falciparum cGMP-dependent protein kinase (PfPKG) is a key regulator across the malaria parasite life cycle. Little is known about PfPKG’s activation mechanism. Here we report that the carboxyl cyclic nucleotide binding domain functions as a “gatekeeper” for activation by providing the highest cGMP affinity and selectivity. To understand the mechanism, we have solved its crystal structures with and without cGMP at 2.0 and 1.9 Å, respectively. These structures revealed a PfPKG-specific capping triad that forms upon cGMP binding, and disrupting the triad reduces kinase activity by 90%. Furthermore, mutating these residues in the parasite prevents blood stage merozoite egress, confirming the essential nature of the triad in the parasite. We propose a mechanism of activation where cGMP binding allosterically triggers the conformational change at the αC-helix, which bridges the regulatory and catalytic domains, causing the capping triad to form and stabilize the active conformation. Malaria causes up to a million fatalities per year worldwide. Most of these deaths are caused by Plasmodium falciparum, which has a complex life cycle in both humans and mosquitoes. One key regulator of this process is P. falciparum cGMP-dependent protein kinase (PfPKG), the main effector of the cGMP-signaling pathway. Specifically blocking this kinase stops both replication and transmission of the parasites, suggesting that PfPKG is a promising drug target. Here we identified the carboxyl cGMP-binding domain of PfPKG serving as a gatekeeper for activation of the entire kinase by having the highest affinity and selectivity for cGMP. High-resolution crystal structures with and without cGMP allowed us to identify a novel cGMP capping triad that dynamically forms upon binding cGMP and stabilizes the activated conformation. Mutation of the capping triad forming residues not only reduces its kinase activity, but also prevents blood stage merozoite egress, demonstrating its crucial role in PfPKG activation.
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Affiliation(s)
- Jeong Joo Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | - Christian Flueck
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Eugen Franz
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | | | - Eloise Thompson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Robin Lorenz
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | - Daniela Bertinetti
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | - David A. Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Choel Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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15
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Abstract
Host cell invasion by Toxoplasma gondii and other apicomplexan parasites requires transmembrane adhesins that mediate binding to receptors on the substrate and host cell to facilitate motility and invasion. Rhomboid proteases (ROMs) are thought to cleave adhesins within their transmembrane segments, thus allowing the parasite to disengage from receptors and completely enter the host cell. To examine the specific roles of individual ROMs during invasion, we generated single, double, and triple knockouts for the three ROMs expressed in T. gondii tachyzoites. Analysis of these mutants demonstrated that ROM4 is the primary protease involved in adhesin processing and host cell invasion, whereas ROM1 or ROM5 plays negligible roles in these processes. Deletion of ROM4 blocked the shedding of adhesins such as MIC2 (microneme protein 2), causing them to accumulate on the surface of extracellular parasites. Increased surface adhesins led to nonproductive attachment, altered gliding motility, impaired moving junction formation, and reduced invasion efficiency. Despite the importance of ROM4 for efficient invasion, mutants lacking all three ROMs were viable and MIC2 was still efficiently removed from the surface of invaded mutant parasites, implying the existence of ROM-independent mechanisms for adhesin removal during invasion. Collectively, these results suggest that although ROM processing of adhesins is not absolutely essential, it is important for efficient host cell invasion by T. gondii. Apicomplexan parasites such as Toxoplasma gondii express surface proteins that bind host cell receptors to aid invasion. Many of these adhesins are subject to cleavage by rhomboid proteases (ROMs) within their transmembrane segments during invasion. Previous studies have demonstrated the importance of adhesin cleavage for parasite invasion and proposed that the ROMs responsible for processing would be essential for parasite survival. In T. gondii, ROM5 was thought to be the critical ROM for adhesin shedding due to its robust protease activity in vitro and posterior localization on the parasite surface. Here, we knocked out all three ROMs in T. gondii tachyzoites and found that ROM4, but not ROM5, was key for adhesin cleavage. However, none of the ROMs individually or in combination was essential for cell entry, further emphasizing that essential pathways such as invasion typically rely on redundant pathways to ensure survival.
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16
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Bargieri D, Lagal V, Andenmatten N, Tardieux I, Meissner M, Ménard R. Host cell invasion by apicomplexan parasites: the junction conundrum. PLoS Pathog 2014; 10:e1004273. [PMID: 25232721 PMCID: PMC4169498 DOI: 10.1371/journal.ppat.1004273] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Daniel Bargieri
- Institut Pasteur, Malaria Biology and Genetics Unit, Department of Parasitology and Mycology, Paris, France
| | - Vanessa Lagal
- Institut Cochin, Laboratory Barriers and Pathogens, INSERM U-1016, CNRS UMR-8104, University of Paris Descartes, Paris, France
| | - Nicole Andenmatten
- Institute of Infection, Immunity and Inflammation, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Isabelle Tardieux
- Institut Cochin, Laboratory Barriers and Pathogens, INSERM U-1016, CNRS UMR-8104, University of Paris Descartes, Paris, France
| | - Markus Meissner
- Institute of Infection, Immunity and Inflammation, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Robert Ménard
- Institut Pasteur, Malaria Biology and Genetics Unit, Department of Parasitology and Mycology, Paris, France
- * E-mail:
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17
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Harvey KL, Yap A, Gilson PR, Cowman AF, Crabb BS. Insights and controversies into the role of the key apicomplexan invasion ligand, Apical Membrane Antigen 1. Int J Parasitol 2014; 44:853-7. [PMID: 25157917 DOI: 10.1016/j.ijpara.2014.08.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 08/04/2014] [Accepted: 08/06/2014] [Indexed: 10/24/2022]
Abstract
Apicomplexan parasites are obligate intracellular pathogens that cause a host of human and animal diseases. These parasites have developed a universal mechanism of invasion involving formation of a 'moving junction' that provides a stable anchoring point through which the parasite invades host cells. The composition of the moving junction, particularly the presence of the protein Apical Membrane Antigen 1 (AMA1), has recently been the subject of some controversy. In this commentary we review findings that led to the current model of the moving junction complex and dissect the major conflicts to determine whether a substantial reassessment of the role of AMA1 is justified.
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Affiliation(s)
- Katherine L Harvey
- Centre for Biomedical Research, Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia; Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Alan Yap
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria 3010, Australia; Infection and Immunity Division, Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - Paul R Gilson
- Centre for Biomedical Research, Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia; Department of Immunology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Alan F Cowman
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria 3010, Australia; Infection and Immunity Division, Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - Brendan S Crabb
- Centre for Biomedical Research, Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia; Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria 3010, Australia; Department of Immunology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia.
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18
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Smith RC, Colón-López DD, Bosch J. Immunization against a merozoite sheddase promotes multiple invasion of red blood cells and attenuates Plasmodium infection in mice. Malar J 2014; 13:313. [PMID: 25115675 PMCID: PMC4248431 DOI: 10.1186/1475-2875-13-313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 08/05/2014] [Indexed: 12/31/2022] Open
Abstract
Background Subtilisin-like protease 2 (SUB2) is a conserved serine protease utilized by Plasmodium parasites as a surface sheddase required for successful merozoite invasion of host red blood cells and has been implicated in ookinete invasion of the mosquito midgut. To determine if SUB2 is a suitable vaccine target to interfere with malaria parasite development, the effects of SUB2-immunization on the Plasmodium life cycle were examined in its vertebrate and invertebrate hosts. Methods Swiss Webster mice were immunized with SUB2 peptides conjugated to Keyhole limpet hemocyanin (KLH) or KLH alone, and then challenged with Plasmodium berghei. To determine the effects of immunization on parasite development, infected mice were evaluated by blood film and Giemsa staining. In addition, collected immune sera were used to perform passive immunization experiments in non-immunized, P. berghei-infected mice to determine the potential role of SUB2 in parasite development in the mosquito. Results Following P. berghei challenge, SUB2-immunized mice develop a lower parasitaemia and show improved survival when compared to control immunized mice. Moreover, SUB2 immunization results in an increase in the number of multiply invaded red blood cells, suggesting that SUB2 antibodies interfere with merozoite invasion. Passive immunization experiments imply that SUB2 may not have a major role in ookinete invasion, but this requires further investigation. Conclusion By interfering with red blood cell invasion, immunization against SUB2 limits malaria parasite development and confers protection from severe malaria. Together, these results provide proof-of-principle evidence for future investigation into the use of SUB2 as a vaccine or drug target to interrupt parasite development in more relevant human malaria models. Electronic supplementary material The online version of this article (doi:10.1186/1475-2875-13-313) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | - Jürgen Bosch
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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19
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Dutta S, Dlugosz LS, Drew DR, Ge X, Ababacar D, Rovira YI, Moch JK, Shi M, Long CA, Foley M, Beeson JG, Anders RF, Miura K, Haynes JD, Batchelor AH. Overcoming antigenic diversity by enhancing the immunogenicity of conserved epitopes on the malaria vaccine candidate apical membrane antigen-1. PLoS Pathog 2013; 9:e1003840. [PMID: 24385910 PMCID: PMC3873463 DOI: 10.1371/journal.ppat.1003840] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 11/04/2013] [Indexed: 12/16/2022] Open
Abstract
Malaria vaccine candidate Apical Membrane Antigen-1 (AMA1) induces protection, but only against parasite strains that are closely related to the vaccine. Overcoming the AMA1 diversity problem will require an understanding of the structural basis of cross-strain invasion inhibition. A vaccine containing four diverse allelic proteins 3D7, FVO, HB3 and W2mef (AMA1 Quadvax or QV) elicited polyclonal rabbit antibodies that similarly inhibited the invasion of four vaccine and 22 non-vaccine strains of P. falciparum. Comparing polyclonal anti-QV with antibodies against a strain-specific, monovalent, 3D7 AMA1 vaccine revealed that QV induced higher levels of broadly inhibitory antibodies which were associated with increased conserved face and domain-3 responses and reduced domain-2 response. Inhibitory monoclonal antibodies (mAb) raised against the QV reacted with a novel cross-reactive epitope at the rim of the hydrophobic trough on domain-1; this epitope mapped to the conserved face of AMA1 and it encompassed the 1e-loop. MAbs binding to the 1e-loop region (1B10, 4E8 and 4E11) were ∼10-fold more potent than previously characterized AMA1-inhibitory mAbs and a mode of action of these 1e-loop mAbs was the inhibition of AMA1 binding to its ligand RON2. Unlike the epitope of a previously characterized 3D7-specific mAb, 1F9, the 1e-loop inhibitory epitope was partially conserved across strains. Another novel mAb, 1E10, which bound to domain-3, was broadly inhibitory and it blocked the proteolytic processing of AMA1. By itself mAb 1E10 was weakly inhibitory but it synergized with a previously characterized, strain-transcending mAb, 4G2, which binds close to the hydrophobic trough on the conserved face and inhibits RON2 binding to AMA1. Novel inhibition susceptible regions and epitopes, identified here, can form the basis for improving the antigenic breadth and inhibitory response of AMA1 vaccines. Vaccination with a few diverse antigenic proteins could provide universal coverage by redirecting the immune response towards conserved epitopes. Numerous reports of vaccine failure are attributed to a mismatch between the genotype of the vaccine and the circulating target strains. This observation is congruent to the view that polyvalent vaccines protect broadly by inducing a multitude of type-specific antibodies. Polyvalent vaccines that can overcome antigenic diversity by refocusing antibody responses towards conserved functional epitopes are highly desirable. Development of an Apical Membrane Antigen-1 (AMA1) malaria vaccine has been impeded by extreme antigenic diversity in the field. We present here a solution to the AMA1 diversity problem. Antibodies against a mixture of only four naturally occurring AMA1 allelic proteins “Quadvax” inhibited invasion of red blood cells by a diverse panel of malaria parasites that represented the global diversity of AMA1 in the field. Competition experiments suggested that in addition to improving the diversity of strain-specific antibodies, the mechanism of broadened inhibition involved an increase in responses against conserved inhibitory epitopes. Monoclonal antibodies against the Quadvax inhibited invasion either by blocking the binding of AMA1 to its receptor RON2 or by blocking a crucial proteolytic processing event. Some mixtures of these antibodies were much more effective than expected and were shown to act synergistically. Together these two classes of functional invasion inhibitory epitopes can be targeted to engineer a more potent AMA1 vaccine.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/immunology
- Antigenic Variation/genetics
- Antigenic Variation/immunology
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Cells, Cultured
- Conserved Sequence/immunology
- Epitope Mapping
- Epitopes/genetics
- Epitopes/immunology
- Immunity, Humoral
- Malaria Vaccines/chemistry
- Malaria Vaccines/immunology
- Membrane Proteins/chemistry
- Membrane Proteins/genetics
- Membrane Proteins/immunology
- Mice
- Mice, Nude
- Models, Molecular
- Plasmodium berghei/genetics
- Plasmodium berghei/immunology
- Plasmodium falciparum/immunology
- Protein Structure, Tertiary
- Protozoan Proteins/chemistry
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- Rabbits
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/immunology
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Affiliation(s)
- Sheetij Dutta
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- * E-mail:
| | - Lisa S. Dlugosz
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | | | - Xiopeng Ge
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | - Diouf Ababacar
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - Yazmin I. Rovira
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - J. Kathleen Moch
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Meng Shi
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Carole A. Long
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - Michael Foley
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | | | - Robin F. Anders
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - J. David Haynes
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Adrian H. Batchelor
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
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20
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Sibley LD. The roles of intramembrane proteases in protozoan parasites. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2908-15. [PMID: 24099008 DOI: 10.1016/j.bbamem.2013.04.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/02/2013] [Accepted: 04/11/2013] [Indexed: 11/30/2022]
Abstract
Intramembrane proteolysis is widely conserved throughout different forms of life, with three major types of proteases being known for their ability to cleave peptide bonds directly within the transmembrane domains of their substrates. Although intramembrane proteases have been extensively studied in humans and model organisms, they have only more recently been investigated in protozoan parasites, where they turn out to play important and sometimes unexpected roles. Signal peptide peptidases are involved in endoplasmic reticulum (ER) quality control and signal peptide degradation from exported proteins. Recent studies suggest that repurposing inhibitors developed for blocking presenilins may be useful for inhibiting the growth of Plasmodium, and possibly other protozoan parasites, by blocking signal peptide peptidases. Rhomboid proteases, originally described in the fly, are also widespread in parasites, and are especially expanded in apicomplexans. Their study in parasites has revealed novel roles that expand our understanding of how these proteases function. Within this diverse group of parasites, rhomboid proteases contribute to processing of adhesins involved in attachment, invasion, intracellular replication, phagocytosis, and immune evasion, placing them at the vertex of host-parasite interactions. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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21
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Arnott A, Mueller I, Ramsland PA, Siba PM, Reeder JC, Barry AE. Global Population Structure of the Genes Encoding the Malaria Vaccine Candidate, Plasmodium vivax Apical Membrane Antigen 1 (PvAMA1). PLoS Negl Trop Dis 2013; 7:e2506. [PMID: 24205419 PMCID: PMC3814406 DOI: 10.1371/journal.pntd.0002506] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/16/2013] [Indexed: 12/22/2022] Open
Abstract
Background The Plasmodium vivax Apical Membrane Antigen 1 (PvAMA1) is a promising malaria vaccine candidate, however it remains unclear which regions are naturally targeted by host immunity and whether its high genetic diversity will preclude coverage by a monovalent vaccine. To assess its feasibility as a vaccine candidate, we investigated the global population structure of PvAMA1. Methodology and Principal Findings New sequences from Papua New Guinea (PNG, n = 102) were analysed together with published sequences from Thailand (n = 158), India (n = 8), Sri Lanka (n = 23), Venezuela (n = 74) and a collection of isolates from disparate geographic locations (n = 8). A total of 92 single nucleotide polymorphisms (SNPs) were identified including 22 synonymous SNPs and 70 non-synonymous (NS) SNPs. Polymorphisms and signatures of balancing (positive Tajima's D and low FST values) selection were predominantly clustered in domain I, suggesting it is a dominant target of protective immune responses. To estimate global antigenic diversity, haplotypes comprised of (i) non-singleton (n = 40) and (ii) common (≥10% minor allele frequency, n = 23) polymorphic amino acid sites were then analysed revealing a total of 219 and 210 distinct haplotypes, respectively. Although highly diverse, the 210 haplotypes comprised of only common polymorphisms were grouped into eleven clusters, however substantial geographic differentiation was observed, and this may have implications for the efficacy of PvAMA1 vaccines in different malaria-endemic areas. The PNG haplotypes form a distinct group of clusters not found in any other geographic region. Vaccine haplotypes were rare and geographically restricted, suggesting potentially poor efficacy of candidate PvAMA1 vaccines. Conclusions It may be possible to cover the existing global PvAMA1 diversity by selection of diverse alleles based on these analyses however it will be important to first define the relationships between the genetic and antigenic diversity of this molecule. Traditionally misclassified as benign and neglected as a research priority, it is now understood that P. vivax is an increasingly important cause of human malaria. This important human pathogen poses an enormous obstacle to malaria control and elimination efforts due its broad geographic distribution, ability to cause recurring episodes of malaria after long periods of inactivity and extreme biodiversity. Vaccines are an essential component of global malaria control and elimination campaigns but the diversity of malaria antigens is thought to be a major cause of vaccine failure. Furthermore, at present the majority of current vaccine research is directed toward P. falciparum. The aims of this study were to investigate the global diversity of the P. vivax vaccine candidate, Apical Membrane Antigen 1 (PvAMA1), to determine the feasibility of designing a globally effective PvAMA1 vaccine and to determine which region of PvAMA1 is targeted by host immune responses, in order to identify the most promising vaccine candidates. We report that PvAMA1 diversity is extremely high, and that PvAMA1 domain I is a dominant target of host immune responses. These analyses of PvAMA1 diversity from several geographic regions provide a framework to guide development of a broadly efficacious P. vivax vaccine.
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Affiliation(s)
- Alicia Arnott
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
| | - Ivo Mueller
- Barcelona Centre for International Health Research, Barcelona, Spain
- Division of Infection and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Paul A. Ramsland
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
- Department of Immunology, Monash University, Melbourne, Australia
- Department of Surgery Austin Health, University of Melbourne, Heidelberg, Australia
- School of Biomedical Sciences, CHIRI Biosciences, Faculty of Health Sciences, Curtin University, Perth, Australia
| | - Peter M. Siba
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea
| | - John C. Reeder
- Centre for Population Health, Burnet Institute, Melbourne, Australia
- Department of Epidemiology and Preventative Medicine, Monash University, Melbourne, Australia
| | - Alyssa E. Barry
- Division of Infection and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- * E-mail:
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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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Immunization with apical membrane antigen 1 confers sterile infection-blocking immunity against Plasmodium sporozoite challenge in a rodent model. Infect Immun 2013; 81:3586-99. [PMID: 23836827 DOI: 10.1128/iai.00544-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Apical membrane antigen 1 (AMA-1) is a leading blood-stage malaria vaccine candidate. Consistent with a key role in erythrocytic invasion, AMA-1-specific antibodies have been implicated in AMA-1-induced protective immunity. AMA-1 is also expressed in sporozoites and in mature liver schizonts where it may be a target of protective cell-mediated immunity. Here, we demonstrate for the first time that immunization with AMA-1 can induce sterile infection-blocking immunity against Plasmodium sporozoite challenge in 80% of immunized mice. Significantly higher levels of gamma interferon (IFN-γ)/interleukin-2 (IL-2)/tumor necrosis factor (TNF) multifunctional T cells were noted in immunized mice than in control mice. We also report the first identification of minimal CD8(+) and CD4(+) T cell epitopes on Plasmodium yoelii AMA-1. These data establish AMA-1 as a target of both preerythrocytic- and erythrocytic-stage protective immune responses and validate vaccine approaches designed to induce both cellular and humoral immunity.
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24
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Lin JW, Meireles P, Prudêncio M, Engelmann S, Annoura T, Sajid M, Chevalley-Maurel S, Ramesar J, Nahar C, Avramut CMC, Koster AJ, Matuschewski K, Waters AP, Janse CJ, Mair GR, Khan SM. Loss-of-function analyses defines vital and redundant functions of the Plasmodium rhomboid protease family. Mol Microbiol 2013; 88:318-38. [PMID: 23490234 DOI: 10.1111/mmi.12187] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/13/2013] [Indexed: 11/26/2022]
Abstract
Rhomboid-like proteases cleave membrane-anchored proteins within their transmembrane domains. In apicomplexan parasites substrates include molecules that function in parasite motility and host cell invasion. While two Plasmodium rhomboids, ROM1 and ROM4, have been examined, the roles of the remaining six rhomboids during the malaria parasite's life cycle are unknown. We present systematic gene deletion analyses of all eight Plasmodium rhomboid-like proteins as a means to discover stage-specific phenotypes and potential functions in the rodent malaria model, P. berghei. Four rhomboids (ROM4, 6, 7 and 8) are refractory to gene deletion, suggesting an essential role during asexual blood stage development. In contrast ROM1, 3, 9 and 10 were dispensable for blood stage development and exhibited no, subtle or severe defects in mosquito or liver development. Parasites lacking ROM9 and ROM10 showed no major phenotypic defects. Parasites lacking ROM1 presented a delay in blood stage patency following liver infection, but in contrast to a previous study blood stage parasites had similar growth and virulence characteristics as wild type parasites. Parasites lacking ROM3 in mosquitoes readily established oocysts but failed to produce sporozoites. ROM3 is the first apicomplexan rhomboid identified to play a vital role in sporogony.
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Affiliation(s)
- Jing-Wen Lin
- Leiden Malaria Research Group (Parasitology), Leiden University Medical Centre, Leiden, The Netherlands
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25
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Adaptation of the genetically tractable malaria pathogen Plasmodium knowlesi to continuous culture in human erythrocytes. Proc Natl Acad Sci U S A 2012; 110:531-6. [PMID: 23267069 DOI: 10.1073/pnas.1216457110] [Citation(s) in RCA: 185] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Research into the aetiological agent of the most widespread form of severe malaria, Plasmodium falciparum, has benefitted enormously from the ability to culture and genetically manipulate blood-stage forms of the parasite in vitro. However, most malaria outside Africa is caused by a distinct Plasmodium species, Plasmodium vivax, and it has become increasingly apparent that zoonotic infection by the closely related simian parasite Plasmodium knowlesi is a frequent cause of life-threatening malaria in regions of southeast Asia. Neither of these important malarial species can be cultured in human cells in vitro, requiring access to primates with the associated ethical and practical constraints. We report the successful adaptation of P. knowlesi to continuous culture in human erythrocytes. Human-adapted P. knowlesi clones maintain their capacity to replicate in monkey erythrocytes and can be genetically modified with unprecedented efficiency, providing an important and unique model for studying conserved aspects of malarial biology as well as species-specific features of an emerging pathogen.
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26
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Ruecker A, Shea M, Hackett F, Suarez C, Hirst EMA, Milutinovic K, Withers-Martinez C, Blackman MJ. Proteolytic activation of the essential parasitophorous vacuole cysteine protease SERA6 accompanies malaria parasite egress from its host erythrocyte. J Biol Chem 2012; 287:37949-63. [PMID: 22984267 PMCID: PMC3488066 DOI: 10.1074/jbc.m112.400820] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 09/04/2012] [Indexed: 12/22/2022] Open
Abstract
The malaria parasite replicates within an intraerythrocytic parasitophorous vacuole (PV). The PV and host cell membranes eventually rupture, releasing merozoites in a process called egress. Certain inhibitors of serine and cysteine proteases block egress, indicating a crucial role for proteases. The Plasmodium falciparum genome encodes nine serine-repeat antigens (SERAs), each of which contains a central domain homologous to the papain-like (clan CA, family C1) protease family. SERA5 and SERA6 are indispensable in blood-stage parasites, but the function of neither is known. Here we show that SERA6 localizes to the PV where it is precisely cleaved just prior to egress by an essential serine protease called PfSUB1. Mutations that replace the predicted catalytic Cys of SERA6, or that block SERA6 processing by PfSUB1, could not be stably introduced into the parasite genomic sera6 locus, indicating that SERA6 is an essential enzyme and that processing is important for its function. We demonstrate that cleavage of SERA6 by PfSUB1 converts it to an active cysteine protease. Our observations reveal a proteolytic activation step in the malarial PV that may be required for release of the parasite from its host erythrocyte.
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Affiliation(s)
- Andrea Ruecker
- From the Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | - Michael Shea
- From the Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | - Fiona Hackett
- From the Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | - Catherine Suarez
- From the Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | - Elizabeth M. A. Hirst
- From the Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | - Katarina Milutinovic
- From the Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | - Chrislaine Withers-Martinez
- From the Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | - Michael J. Blackman
- From the Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
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27
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He Y, Chen Y, Oganesyan N, Ruan B, O'Brochta D, Bryan PN, Orban J. Solution NMR structure of a sheddase inhibitor prodomain from the malarial parasite Plasmodium falciparum. Proteins 2012; 80:2810-7. [PMID: 23011838 DOI: 10.1002/prot.24187] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 09/06/2012] [Accepted: 09/19/2012] [Indexed: 11/10/2022]
Abstract
Plasmodium subtilisin 2 (Sub2) is a multidomain protein that plays an important role in malaria infection. Here, we describe the solution NMR structure of a conserved region of the inhibitory prodomain of Sub2 from Plasmodium falciparum, termed prosub2. Despite the absence of any detectable sequence homology, the protozoan prosub2 has structural similarity to bacterial and mammalian subtilisin-like prodomains. Comparison with the three-dimensional structures of these other prodomains suggests a likely binding interface with the catalytic domain of Sub2 and provides insights into the locations of primary and secondary processing sites in Plasmodium prodomains.
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Affiliation(s)
- Yanan He
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
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28
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Jacot D, Soldati-Favre D. Does protein phosphorylation govern host cell entry and egress by the Apicomplexa? Int J Med Microbiol 2012; 302:195-202. [DOI: 10.1016/j.ijmm.2012.07.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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29
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Structural basis for the sheddase function of human meprin β metalloproteinase at the plasma membrane. Proc Natl Acad Sci U S A 2012; 109:16131-6. [PMID: 22988105 DOI: 10.1073/pnas.1211076109] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Ectodomain shedding at the cell surface is a major mechanism to regulate the extracellular and circulatory concentration or the activities of signaling proteins at the plasma membrane. Human meprin β is a 145-kDa disulfide-linked homodimeric multidomain type-I membrane metallopeptidase that sheds membrane-bound cytokines and growth factors, thereby contributing to inflammatory diseases, angiogenesis, and tumor progression. In addition, it cleaves amyloid precursor protein (APP) at the β-secretase site, giving rise to amyloidogenic peptides. We have solved the X-ray crystal structure of a major fragment of the meprin β ectoprotein, the first of a multidomain oligomeric transmembrane sheddase, and of its zymogen. The meprin β dimer displays a compact shape, whose catalytic domain undergoes major rearrangement upon activation, and reveals an exosite and a sugar-rich channel, both of which possibly engage in substrate binding. A plausible structure-derived working mechanism suggests that substrates such as APP are shed close to the plasma membrane surface following an "N-like" chain trace.
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30
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Intramembrane proteolysis of Toxoplasma apical membrane antigen 1 facilitates host-cell invasion but is dispensable for replication. Proc Natl Acad Sci U S A 2012; 109:7463-8. [PMID: 22523242 DOI: 10.1073/pnas.1114661109] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Apical membrane antigen 1 (AMA1) is a conserved transmembrane adhesin of apicomplexan parasites that plays an important role in host-cell invasion. Toxoplasma gondii AMA1 (TgAMA1) is secreted onto the parasite surface and subsequently released by proteolytic cleavage within its transmembrane domain. To elucidate the function of TgAMA1 intramembrane proteolysis, we used a heterologous cleavage assay to characterize the determinants within the TgAMA1 transmembrane domain (ALIAGLAVGGVLLLALLGGGCYFA) that govern its processing. Quantitative analysis revealed that the TgAMA1(L/G) mutation enhanced cleavage by 13-fold compared with wild type. In contrast, the TgAMA1(AG/FF) mutation reduced cleavage by 30-fold, whereas the TgAMA1(GG/FF) mutation had a minor effect on proteolysis; mutating both motifs in a quadruple mutant blocked cleavage completely. We then complemented a TgAMA1 conditional knockout parasite line with plasmids expressing these TgAMA1 variants. Contrary to expectation, variants that increased or decreased TgAMA1 processing by >10-fold had no phenotypic consequences, revealing that the levels of rhomboid proteolysis in parasites are not delicately balanced. Only parasites transgenically expressing or carrying a true knock-in allele of the uncleavable TgAMA1(AG/FF+GG/FF) mutant showed a growth defect, which resulted from inhibiting invasion without perturbing intracellular replication. These data demonstrate that TgAMA1 cleavage plays a role in invasion, but refute a recently proposed model in which parasite replication within the host cell is regulated by intramembrane proteolysis of TgAMA1.
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31
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Shen B, Sibley LD. The moving junction, a key portal to host cell invasion by apicomplexan parasites. Curr Opin Microbiol 2012; 15:449-55. [PMID: 22445360 DOI: 10.1016/j.mib.2012.02.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 02/23/2012] [Indexed: 10/28/2022]
Abstract
One defining feature of apicomplexan parasites is their special ability to actively invade host cells. Although rapid, invasion is a complicated process that requires coordinated activities of host cell attachment, protein secretion, and motility by the parasite. Central to this process is the establishment of a structure called moving junction (MJ), which forms a tight connection between invading parasite and host cell membranes through which the parasite passes to enter into the host. Although recognized microscopically for decades, molecular characterization of the MJ was only enabled by the recent discovery of components that make up this multi-protein complex. Exciting progress made during the past few years on both the structure and function of the components of the MJ is reviewed here.
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Affiliation(s)
- Bang Shen
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
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32
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Bargieri D, Lagal V, Tardieux I, Ménard R. Host cell invasion by apicomplexans: what do we know? Trends Parasitol 2012; 28:131-5. [PMID: 22326913 DOI: 10.1016/j.pt.2012.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 01/21/2012] [Accepted: 01/23/2012] [Indexed: 10/14/2022]
Abstract
Apicomplexan zoites enter host cells by forming and actively moving through a tight junction (TJ) formed between the parasite and host cell surfaces. Although the TJ was first described decades ago, its molecular characterization has proved difficult mainly because of its transient existence during an internalization process that lasts only seconds. In the past 7 years, work has led to a model of the TJ in which the association between AMA1 and RON proteins structures the TJ and bridges the cytoskeletons of the two cells. However, more recent work questions this view. Here, we critically discuss the current model and speculate on alternative models of the AMA1-RON association and of the apicomplexan TJ.
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Affiliation(s)
- Daniel Bargieri
- Institut Pasteur, Unité de Biologie et Génétique du Paludisme, 75015 Paris, France
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