1
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McConville R, Krol JMM, Steel RWJ, O’Neill MT, Davey BK, Hodder AN, Nebl T, Cowman AF, Kneteman N, Boddey JA. Flp/ FRT-mediated disruption of ptex150 and exp2 in Plasmodium falciparum sporozoites inhibits liver-stage development. Proc Natl Acad Sci U S A 2024; 121:e2403442121. [PMID: 38968107 PMCID: PMC11252984 DOI: 10.1073/pnas.2403442121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 05/31/2024] [Indexed: 07/07/2024] Open
Abstract
Plasmodium falciparum causes severe malaria and assembles a protein translocon (PTEX) complex at the parasitophorous vacuole membrane (PVM) of infected erythrocytes, through which several hundred proteins are exported to facilitate growth. The preceding liver stage of infection involves growth in a hepatocyte-derived PVM; however, the importance of protein export during P. falciparum liver infection remains unexplored. Here, we use the FlpL/FRT system to conditionally excise genes in P. falciparum sporozoites for functional liver-stage studies. Disruption of PTEX members ptex150 and exp2 did not affect sporozoite development in mosquitoes or infectivity for hepatocytes but attenuated liver-stage growth in humanized mice. While PTEX150 deficiency reduced fitness on day 6 postinfection by 40%, EXP2 deficiency caused 100% loss of liver parasites, demonstrating that PTEX components are required for growth in hepatocytes to differing degrees. To characterize PTEX loss-of-function mutations, we localized four liver-stage Plasmodium export element (PEXEL) proteins. P. falciparum liver specific protein 2 (LISP2), liver-stage antigen 3 (LSA3), circumsporozoite protein (CSP), and a Plasmodium berghei LISP2 reporter all localized to the periphery of P. falciparum liver stages but were not exported beyond the PVM. Expression of LISP2 and CSP but not LSA3 was reduced in ptex150-FRT and exp2-FRT liver stages, suggesting that expression of some PEXEL proteins is affected directly or indirectly by PTEX disruption. These results show that PTEX150 and EXP2 are important for P. falciparum development in hepatocytes and emphasize the emerging complexity of PEXEL protein trafficking.
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Affiliation(s)
- Robyn McConville
- Division of Infectious Diseases & Immune Defence, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC3052, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC3010, Australia
| | - Jelte M. M. Krol
- Division of Infectious Diseases & Immune Defence, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC3052, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC3010, Australia
| | - Ryan W. J. Steel
- Division of Infectious Diseases & Immune Defence, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC3052, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC3010, Australia
| | - Matthew T. O’Neill
- Division of Infectious Diseases & Immune Defence, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC3052, Australia
| | - Bethany K. Davey
- Division of Infectious Diseases & Immune Defence, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC3052, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC3010, Australia
| | - Anthony N. Hodder
- Division of Infectious Diseases & Immune Defence, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC3052, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC3010, Australia
| | - Thomas Nebl
- Division of Infectious Diseases & Immune Defence, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC3052, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC3010, Australia
| | - Alan F. Cowman
- Division of Infectious Diseases & Immune Defence, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC3052, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC3010, Australia
| | - Norman Kneteman
- Departments of Surgery, University of Alberta, Edmonton, ABT6G 2E1, Canada
| | - Justin A. Boddey
- Division of Infectious Diseases & Immune Defence, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC3052, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC3010, Australia
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2
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Hollin T, Abel S, Banks C, Hristov B, Prudhomme J, Hales K, Florens L, Stafford Noble W, Le Roch KG. Proteome-Wide Identification of RNA-dependent proteins and an emerging role for RNAs in Plasmodium falciparum protein complexes. Nat Commun 2024; 15:1365. [PMID: 38355719 PMCID: PMC10866993 DOI: 10.1038/s41467-024-45519-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 01/26/2024] [Indexed: 02/16/2024] Open
Abstract
Ribonucleoprotein complexes are composed of RNA, RNA-dependent proteins (RDPs) and RNA-binding proteins (RBPs), and play fundamental roles in RNA regulation. However, in the human malaria parasite, Plasmodium falciparum, identification and characterization of these proteins are particularly limited. In this study, we use an unbiased proteome-wide approach, called R-DeeP, a method based on sucrose density gradient ultracentrifugation, to identify RDPs. Quantitative analysis by mass spectrometry identifies 898 RDPs, including 545 proteins not yet associated with RNA. Results are further validated using a combination of computational and molecular approaches. Overall, this method provides the first snapshot of the Plasmodium protein-protein interaction network in the presence and absence of RNA. R-DeeP also helps to reconstruct Plasmodium multiprotein complexes based on co-segregation and deciphers their RNA-dependence. One RDP candidate, PF3D7_0823200, is functionally characterized and validated as a true RBP. Using enhanced crosslinking and immunoprecipitation followed by high-throughput sequencing (eCLIP-seq), we demonstrate that this protein interacts with various Plasmodium non-coding transcripts, including the var genes and ap2 transcription factors.
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Affiliation(s)
- Thomas Hollin
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA, USA
| | - Steven Abel
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA, USA
| | - Charles Banks
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Borislav Hristov
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Jacques Prudhomme
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA, USA
| | - Kianna Hales
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | | | - William Stafford Noble
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, USA
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA, USA.
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3
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Pitman EL, Counihan NA, Modak JK, Chowdury M, Gilson PR, Webb CT, de Koning-Ward TF. Dissecting EXP2 sequence requirements for protein export in malaria parasites. Front Cell Infect Microbiol 2024; 13:1332146. [PMID: 38282616 PMCID: PMC10811066 DOI: 10.3389/fcimb.2023.1332146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 12/19/2023] [Indexed: 01/30/2024] Open
Abstract
Apicomplexan parasites that reside within a parasitophorous vacuole harbor a conserved pore-forming protein that enables small-molecule transfer across the parasitophorous vacuole membrane (PVM). In Plasmodium parasites that cause malaria, this nutrient pore is formed by EXP2 which can complement the function of GRA17, an orthologous protein in Toxoplasma gondii. EXP2, however, has an additional function in Plasmodium parasites, serving also as the pore-forming component of the protein export machinery PTEX. To examine how EXP2 can play this additional role, transgenes that encoded truncations of EXP2, GRA17, hybrid GRA17-EXP2, or EXP2 under the transcriptional control of different promoters were expressed in EXP2 knockdown parasites to determine which could complement EXP2 function. This revealed that EXP2 is a unique pore-forming protein, and its protein export role in P. falciparum cannot be complemented by T. gondii GRA17. This was despite the addition of the EXP2 assembly strand and part of the linker helix to GRA17, which are regions necessary for the interaction of EXP2 with the other core PTEX components. This indicates that the body region of EXP2 plays a critical role in PTEX assembly and/or that the absence of other T. gondii GRA proteins in P. falciparum leads to its reduced efficiency of insertion into the PVM and complementation potential. Altering the timing and abundance of EXP2 expression did not affect protein export but affected parasite viability, indicating that the unique transcriptional profile of EXP2 when compared to other PTEX components enables it to serve an additional role in nutrient exchange.
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Affiliation(s)
- Ethan L. Pitman
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
| | - Natalie A. Counihan
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
| | - Joyanta K. Modak
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
| | - Mrittika Chowdury
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
| | - Paul R. Gilson
- Burnet Institute, Melbourne, VIC, Australia
- Department of Microbiology and Immunology, University of Melbourne, Parkville, VIC, Australia
| | - Chaille T. Webb
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia
- Centre to Impact AMR, Monash University, Clayton, VIC, Australia
| | - Tania F. de Koning-Ward
- School of Medicine, Deakin University, Geelong, VIC, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
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4
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Siau A, Ang JW, Sheriff O, Hoo R, Loh HP, Tay D, Huang X, Yam XY, Lai SK, Meng W, Julca I, Kwan SS, Mutwil M, Preiser PR. Comparative spatial proteomics of Plasmodium-infected erythrocytes. Cell Rep 2023; 42:113419. [PMID: 37952150 DOI: 10.1016/j.celrep.2023.113419] [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: 02/15/2022] [Revised: 07/14/2023] [Accepted: 10/25/2023] [Indexed: 11/14/2023] Open
Abstract
Plasmodium parasites contribute to one of the highest global infectious disease burdens. To achieve this success, the parasite has evolved a range of specialized subcellular compartments to extensively remodel the host cell for its survival. The information to fully understand these compartments is likely hidden in the so far poorly characterized Plasmodium species spatial proteome. To address this question, we determined the steady-state subcellular location of more than 12,000 parasite proteins across five different species by extensive subcellular fractionation of erythrocytes infected by Plasmodium falciparum, Plasmodium knowlesi, Plasmodium yoelii, Plasmodium berghei, and Plasmodium chabaudi. This comparison of the pan-species spatial proteomes and their expression patterns indicates increasing species-specific proteins associated with the more external compartments, supporting host adaptations and post-transcriptional regulation. The spatial proteome offers comprehensive insight into the different human, simian, and rodent Plasmodium species, establishing a powerful resource for understanding species-specific host adaptation processes in the parasite.
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Affiliation(s)
- Anthony Siau
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Jing Wen Ang
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Omar Sheriff
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Regina Hoo
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Han Ping Loh
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Donald Tay
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Ximei Huang
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Xue Yan Yam
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Soak Kuan Lai
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Wei Meng
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Irene Julca
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Sze Siu Kwan
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Marek Mutwil
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore
| | - Peter R Preiser
- Nanyang Technological University, School of Biological Sciences, Singapore 637551, Singapore.
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5
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Hasan MM, Polino AJ, Mukherjee S, Vaupel B, Goldberg DE. The mature N-termini of Plasmodium effector proteins confer specificity of export. mBio 2023; 14:e0121523. [PMID: 37646514 PMCID: PMC10653839 DOI: 10.1128/mbio.01215-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/10/2023] [Indexed: 09/01/2023] Open
Abstract
IMPORTANCE Malaria parasites export hundreds of proteins to the cytoplasm of the host red blood cells for their survival. A five amino acid sequence, called the PEXEL motif, is conserved among many exported proteins and is thought to be a signal for export. However, the motif is cleaved inside the endoplasmic reticulum of the parasite, and mature proteins starting from the fourth PEXEL residue travel to the parasite periphery for export. We showed that the PEXEL motif is dispensable for export as long as identical mature proteins can be efficiently produced via alternative means in the ER. We also showed that the exported and non-exported proteins are differentiated at the parasite periphery based on their mature N-termini; however, any discernible export signal within that region remained cryptic. Our study resolves a longstanding paradox in PEXEL protein trafficking.
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Affiliation(s)
- Muhammad M. Hasan
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alexander J. Polino
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sumit Mukherjee
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Barbara Vaupel
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Daniel E. Goldberg
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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6
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Almaazmi SY, Kaur RP, Singh H, Blatch GL. The Plasmodium falciparum exported J domain proteins fine-tune human and malarial Hsp70s: pathological exploitation of proteostasis machinery. Front Mol Biosci 2023; 10:1216192. [PMID: 37457831 PMCID: PMC10349383 DOI: 10.3389/fmolb.2023.1216192] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 06/12/2023] [Indexed: 07/18/2023] Open
Abstract
Cellular proteostasis requires a network of molecular chaperones and co-chaperones, which facilitate the correct folding and assembly of other proteins, or the degradation of proteins misfolded beyond repair. The function of the major chaperones, heat shock protein 70 (Hsp70) and heat shock protein 90 (Hsp90), is regulated by a cohort of co-chaperone proteins. The J domain protein (JDP) family is one of the most diverse co-chaperone families, playing an important role in functionalizing the Hsp70 chaperone system to form a powerful protein quality control network. The intracellular malaria parasite, Plasmodium falciparum, has evolved the capacity to invade and reboot mature human erythrocytes, turning them into a vehicles of pathology. This process appears to involve the harnessing of both the human and parasite chaperone machineries. It is well known that malaria parasite-infected erythrocytes are highly enriched in functional human Hsp70 (HsHsp70) and Hsp90 (HsHsp90), while recent proteomics studies have provided evidence that human JDPs (HsJDPs) may also be enriched, but at lower levels. Interestingly, P. falciparum JDPs (PfJDPs) are the most prominent and diverse family of proteins exported into the infected erythrocyte cytosol. We hypothesize that the exported PfJPDs may be an evolutionary consequence of the need to boost chaperone power for specific protein folding pathways that enable both survival and pathogenesis of the malaria parasite. The evidence suggests that there is an intricate network of PfJDP interactions with the exported malarial Hsp70 (PfHsp70-x) and HsHsp70, which appear to be important for the trafficking of key malarial virulence factors, and the proteostasis of protein complexes of human and parasite proteins associated with pathology. This review will critically evaluate the current understanding of the role of exported PfJDPs in pathological exploitation of the proteostasis machinery by fine-tuning the chaperone properties of both human and malarial Hsp70s.
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Affiliation(s)
- Shaikha Y. Almaazmi
- Biomedical Research and Drug Discovery Research Group, Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
| | - Rupinder P. Kaur
- The Department of Chemistry, Guru Nanak Dev University College Verka, Amritsar, Punjab, India
| | - Harpreet Singh
- Department of Bioinformatics, Hans Raj Mahila Maha Vidyalaya, Jalandhar, Punjab, India
| | - Gregory L. Blatch
- Biomedical Research and Drug Discovery Research Group, Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
- Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa
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7
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Jeninga MD, Tang J, Selvarajah SA, Maier AG, Duffy MF, Petter M. Plasmodium falciparum gametocytes display global chromatin remodelling during sexual differentiation. BMC Biol 2023; 21:65. [PMID: 37013531 PMCID: PMC10071754 DOI: 10.1186/s12915-023-01568-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 03/17/2023] [Indexed: 04/05/2023] Open
Abstract
BACKGROUND The protozoan malaria parasite Plasmodium falciparum has a complex life cycle during which it needs to differentiate into multiple morphologically distinct life forms. A key process for transmission of the disease is the development of male and female gametocytes in the human blood, yet the mechanisms determining sexual dimorphism in these haploid, genetically identical sexual precursor cells remain largely unknown. To understand the epigenetic program underlying the differentiation of male and female gametocytes, we separated the two sexual forms by flow cytometry and performed RNAseq as well as comprehensive ChIPseq profiling of several histone variants and modifications. RESULTS We show that in female gametocytes the chromatin landscape is globally remodelled with respect to genome-wide patterns and combinatorial usage of histone variants and histone modifications. We identified sex specific differences in heterochromatin distribution, implicating exported proteins and ncRNAs in sex determination. Specifically in female gametocytes, the histone variants H2A.Z/H2B.Z were highly enriched in H3K9me3-associated heterochromatin. H3K27ac occupancy correlated with stage-specific gene expression, but in contrast to asexual parasites this was unlinked to H3K4me3 co-occupancy at promoters in female gametocytes. CONCLUSIONS Collectively, we defined novel combinatorial chromatin states differentially organising the genome in gametocytes and asexual parasites and unravelled fundamental, sex-specific differences in the epigenetic code. Our chromatin maps represent an important resource for future understanding of the mechanisms driving sexual differentiation in P. falciparum.
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Affiliation(s)
- Myriam D Jeninga
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Jingyi Tang
- Department of Medicine, University of Melbourne, Bio21 Institute, 30 Flemington Road, Parkville, VIC, 3052, Australia
| | - Shamista A Selvarajah
- Department of Medicine, University of Melbourne, Bio21 Institute, 30 Flemington Road, Parkville, VIC, 3052, Australia
| | - Alexander G Maier
- The Australian National University, Research School of Biology, 134 Linnaeus Way, Canberra, ACT, 2601, Australia
| | - Michael F Duffy
- Department of Microbiology and Immunology, University of Melbourne, Peter Doherty Institute, 792 Elizabeth Street, Melbourne, VIC, 3000, Australia
- Bio21 Institute, 30 Flemington Road, Parkville, VIC, 3052, Australia
| | - Michaela Petter
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany.
- Department of Medicine, University of Melbourne, Bio21 Institute, 30 Flemington Road, Parkville, VIC, 3052, Australia.
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8
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A member of the tryptophan-rich protein family is required for efficient sequestration of Plasmodium berghei schizonts. PLoS Pathog 2022; 18:e1010846. [PMID: 36126089 PMCID: PMC9524624 DOI: 10.1371/journal.ppat.1010846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/30/2022] [Accepted: 08/31/2022] [Indexed: 11/20/2022] Open
Abstract
Protein export and host membrane remodeling are crucial for multiple Plasmodium species to establish a niche in infected hosts. To better understand the contribution of these processes to successful parasite infection in vivo, we sought to find and characterize protein components of the intraerythrocytic Plasmodium berghei-induced membrane structures (IBIS) that form in the cytoplasm of infected erythrocytes. We identified proteins that immunoprecipitate with IBIS1, a signature member of the IBIS in P. berghei-infected erythrocytes. In parallel, we also report our data describing proteins that co-precipitate with the PTEX (Plasmodium translocon of exported proteins) component EXP2. To validate our findings, we examined the location of three candidate IBIS1-interactors that are conserved across multiple Plasmodium species, and we found they localized to IBIS in infected red blood cells and two further colocalized with IBIS1 in the liver-stage parasitophorous vacuole membrane. Successful gene deletion revealed that these two tryptophan-rich domain-containing proteins, termed here IPIS2 and IPIS3 (for intraerythrocytic Plasmodium-induced membrane structures), are required for efficient blood-stage growth. Erythrocytes infected with IPIS2-deficient schizonts in particular fail to bind CD36 as efficiently as wild-type P. berghei-infected cells and therefore fail to effectively sequester out of the circulating blood. Our findings support the idea that intra-erythrocytic membrane compartments are required across species for alterations of the host erythrocyte that facilitate interactions of infected cells with host tissues.
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9
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Almaazmi SY, Singh H, Dutta T, Blatch GL. Exported J domain proteins of the human malaria parasite. Front Mol Biosci 2022; 9:978663. [PMID: 36120546 PMCID: PMC9470956 DOI: 10.3389/fmolb.2022.978663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 08/02/2022] [Indexed: 11/21/2022] Open
Abstract
The heat shock protein 40 (Hsp40) family, also called J domain proteins (JDPs), regulate their Hsp70 partners by ensuring that they are engaging the right substrate at the right time and in the right location within the cell. A number of JDPs can serve as co-chaperone for a particular Hsp70, and so one generally finds many more JDPs than Hsp70s in the cell. In humans there are 13 Hsp70s and 49 JDPs. The human malaria parasite, Plasmodium falciparum, has dedicated an unusually large proportion of its genome to molecular chaperones, with a disproportionately high number of JDPs (PfJDPs) of 49 members. Interestingly, just under half of the PfJDPs are exported into the host cell during the asexual stage of the life cycle, when the malaria parasite invades mature red blood cells. Recent evidence suggests that these PfJDPs may be functionalizing both host and parasite Hsp70s within the infected red blood cell, and thereby driving the renovation of the host cell towards pathological ends. PfJDPs have been found to localize to the host cytosol, mobile structures within the host cytosol (so called “J Dots”), the host plasma membrane, and specialized structures associated with malaria pathology such as the knobs. A number of these exported PfJDPs are essential, and there is growing experimental evidence that they are important for the survival and pathogenesis of the malaria parasite. This review critiques our understanding of the important role these exported PfJDPs play at the host-parasite interface.
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Affiliation(s)
- Shaikha Y. Almaazmi
- Biomedical Research and Drug Discovery Research Group, Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
| | - Harpreet Singh
- Department of Bioinformatics, Hans Raj Mahila Maha Vidyalaya, Jalandhar, India
| | - Tanima Dutta
- Vice Chancellery, The University of Notre Dame Australia, Fremantle, WA, Australia
- The Institute of Immunology and Infectious Diseases, Murdoch University, Perth, WA, Australia
- PathWest Nedlands, QEII Medical Centre, Nedlands, WA, Australia
| | - Gregory L. Blatch
- Biomedical Research and Drug Discovery Research Group, Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
- Vice Chancellery, The University of Notre Dame Australia, Fremantle, WA, Australia
- The Institute of Immunology and Infectious Diseases, Murdoch University, Perth, WA, Australia
- Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa
- *Correspondence: Gregory L. Blatch,
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10
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Blatch GL. Plasmodium falciparum Molecular Chaperones: Guardians of the Malaria Parasite Proteome and Renovators of the Host Proteome. Front Cell Dev Biol 2022; 10:921739. [PMID: 35652103 PMCID: PMC9149364 DOI: 10.3389/fcell.2022.921739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 04/28/2022] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum is a unicellular protozoan parasite and causative agent of the most severe form of malaria in humans. The malaria parasite has had to develop sophisticated mechanisms to preserve its proteome under the changing stressful conditions it confronts, particularly when it invades host erythrocytes. Heat shock proteins, especially those that function as molecular chaperones, play a key role in protein homeostasis (proteostasis) of P. falciparum. Soon after invading erythrocytes, the malaria parasite exports a large number of proteins including chaperones, which are responsible for remodeling the infected erythrocyte to enable its survival and pathogenesis. The infected host cell has parasite-resident and erythrocyte-resident chaperones, which appear to play a vital role in the folding and functioning of P. falciparum proteins and potentially host proteins. This review critiques the current understanding of how the major chaperones, particularly the Hsp70 and Hsp40 (or J domain proteins, JDPs) families, contribute to proteostasis of the malaria parasite-infected erythrocytes.
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Affiliation(s)
- Gregory L Blatch
- The Vice Chancellery, The University of Notre Dame Australia, Fremantle, WA, Australia.,Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa.,Biomedical Research and Drug Discovery Research Group, Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
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11
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Bullen HE, Sanders PR, Dans MG, Jonsdottir TK, Riglar DT, Looker O, Palmer CS, Kouskousis B, Charnaud SC, Triglia T, Gabriela M, Schneider MP, Chan J, de Koning‐Ward TF, Baum J, Kazura JW, Beeson JG, Cowman AF, Gilson PR, Crabb BS. The
Plasmodium falciparum
parasitophorous vacuole protein
P113
interacts with the parasite protein export machinery and maintains normal vacuole architecture. Mol Microbiol 2022; 117:1245-1262. [PMID: 35403274 PMCID: PMC9544671 DOI: 10.1111/mmi.14904] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/31/2022] [Accepted: 04/05/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Hayley E. Bullen
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
| | | | - Madeline G. Dans
- Burnet Institute 85 Commercial Road Prahran Australia
- School of Medicine Deakin University Waurn Ponds Victoria Australia
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
| | - Thorey K. Jonsdottir
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
| | - David T. Riglar
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
- Imperial College London Department of Infectious Diseases, South Kensington Campus, SW72AZ UK
| | - Oliver Looker
- Burnet Institute 85 Commercial Road Prahran Australia
| | - Catherine S. Palmer
- Burnet Institute 85 Commercial Road Prahran Australia
- Bio21, 30 Road Parkville Flemington Australia
| | | | - Sarah C. Charnaud
- Burnet Institute 85 Commercial Road Prahran Australia
- WHO Geneva Switzerland
| | - Tony Triglia
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
| | - Mikha Gabriela
- Burnet Institute 85 Commercial Road Prahran Australia
- School of Medicine Deakin University Waurn Ponds Victoria Australia
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
| | | | - Jo‐Anne Chan
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Medicine University of Melbourne Parkville Victoria Australia
| | | | - Jake Baum
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
- Imperial College London Department of Infectious Diseases, South Kensington Campus, SW72AZ UK
| | - James W. Kazura
- Centre for Global Health and Diseases Case Western Reserve University Cleveland Ohio USA
| | - James G. Beeson
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Medicine University of Melbourne Parkville Victoria Australia
- Department of Immunology, Central clinical school Monash University Melbourne Victoria Australia
| | - Alan F. Cowman
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
| | - Paul R. Gilson
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
| | - Brendan S. Crabb
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
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Gabriela M, Matthews KM, Boshoven C, Kouskousis B, Jonsdottir TK, Bullen HE, Modak J, Steer DL, Sleebs BE, Crabb BS, de Koning-Ward TF, Gilson PR. A revised mechanism for how Plasmodium falciparum recruits and exports proteins into its erythrocytic host cell. PLoS Pathog 2022; 18:e1009977. [PMID: 35192672 PMCID: PMC8896661 DOI: 10.1371/journal.ppat.1009977] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 03/04/2022] [Accepted: 02/10/2022] [Indexed: 11/18/2022] Open
Abstract
Plasmodium falciparum exports ~10% of its proteome into its host erythrocyte to modify the host cell's physiology. The Plasmodium export element (PEXEL) motif contained within the N-terminus of most exported proteins directs the trafficking of those proteins into the erythrocyte. To reach the host cell, the PEXEL motif of exported proteins is processed by the endoplasmic reticulum (ER) resident aspartyl protease plasmepsin V. Then, following secretion into the parasite-encasing parasitophorous vacuole, the mature exported protein must be unfolded and translocated across the parasitophorous vacuole membrane by the Plasmodium translocon of exported proteins (PTEX). PTEX is a protein-conducting channel consisting of the pore-forming protein EXP2, the protein unfoldase HSP101, and structural component PTEX150. The mechanism of how exported proteins are specifically trafficked from the parasite's ER following PEXEL cleavage to PTEX complexes on the parasitophorous vacuole membrane is currently not understood. Here, we present evidence that EXP2 and PTEX150 form a stable subcomplex that facilitates HSP101 docking. We also demonstrate that HSP101 localises both within the parasitophorous vacuole and within the parasite's ER throughout the ring and trophozoite stage of the parasite, coinciding with the timeframe of protein export. Interestingly, we found that HSP101 can form specific interactions with model PEXEL proteins in the parasite's ER, irrespective of their PEXEL processing status. Collectively, our data suggest that HSP101 recognises and chaperones PEXEL proteins from the ER to the parasitophorous vacuole and given HSP101's specificity for the EXP2-PTEX150 subcomplex, this provides a mechanism for how exported proteins are specifically targeted to PTEX for translocation into the erythrocyte.
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Affiliation(s)
- Mikha Gabriela
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- School of Medicine, Deakin University, Geelong, Australia
| | - Kathryn M. Matthews
- School of Medicine, Deakin University, Geelong, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Australia
| | - Cas Boshoven
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Betty Kouskousis
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Thorey K. Jonsdottir
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
| | - Hayley E. Bullen
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
| | - Joyanta Modak
- School of Medicine, Deakin University, Geelong, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Australia
| | - David L. Steer
- Monash Biomedical Proteomics and Metabolomics Facility, Monash University, Melbourne, Australia
| | - Brad E. Sleebs
- ACRF Chemical Biology Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Brendan S. Crabb
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Australia
| | - Tania F. de Koning-Ward
- School of Medicine, Deakin University, Geelong, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Australia
| | - Paul R. Gilson
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
- * E-mail:
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13
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PCRCR complex is essential for invasion of human erythrocytes by Plasmodium falciparum. Nat Microbiol 2022; 7:2039-2053. [PMID: 36396942 PMCID: PMC9712106 DOI: 10.1038/s41564-022-01261-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 10/03/2022] [Indexed: 11/18/2022]
Abstract
The most severe form of malaria is caused by Plasmodium falciparum. These parasites invade human erythrocytes, and an essential step in this process involves the ligand PfRh5, which forms a complex with cysteine-rich protective antigen (CyRPA) and PfRh5-interacting protein (PfRipr) (RCR complex) and binds basigin on the host cell. We identified a heteromeric disulfide-linked complex consisting of P. falciparum Plasmodium thrombospondin-related apical merozoite protein (PfPTRAMP) and P. falciparum cysteine-rich small secreted protein (PfCSS) and have shown that it binds RCR to form a pentameric complex, PCRCR. Using P. falciparum lines with conditional knockouts, invasion inhibitory nanobodies to both PfPTRAMP and PfCSS, and lattice light-sheet microscopy, we show that they are essential for merozoite invasion. The PCRCR complex functions to anchor the contact between merozoite and erythrocyte membranes brought together by strong parasite deformations. We solved the structure of nanobody-PfCSS complexes to identify an inhibitory epitope. Our results define the function of the PCRCR complex and identify invasion neutralizing epitopes providing a roadmap for structure-guided development of these proteins for a blood stage malaria vaccine.
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14
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Kreutzfeld O, Grützke J, Ingmundson A, Müller K, Matuschewski K. Absence of PEXEL-Dependent Protein Export in Plasmodium Liver Stages Cannot Be Restored by Gain of the HSP101 Protein Translocon ATPase. Front Genet 2021; 12:742153. [PMID: 34956312 PMCID: PMC8693896 DOI: 10.3389/fgene.2021.742153] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022] Open
Abstract
Host cell remodeling is critical for successful Plasmodium replication inside erythrocytes and achieved by targeted export of parasite-encoded proteins. In contrast, during liver infection the malarial parasite appears to avoid protein export, perhaps to limit exposure of parasite antigens by infected liver cells. HSP101, the force-generating ATPase of the protein translocon of exported proteins (PTEX) is the only component that is switched off during early liver infection. Here, we generated transgenic Plasmodium berghei parasite lines that restore liver stage expression of HSP101. HSP101 expression in infected hepatocytes was achieved by swapping the endogenous promoter with the ptex150 promoter and by inserting an additional copy under the control of the elongation one alpha (ef1α) promoter. Both promoters drive constitutive and, hence, also pre-erythrocytic expression. Transgenic parasites were able to complete the life cycle, but failed to export PEXEL-proteins in early liver stages. Our results suggest that PTEX-dependent early liver stage export cannot be restored by addition of HSP101, indicative of alternative export complexes or other functions of the PTEX core complex during liver infection.
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Affiliation(s)
- Oriana Kreutzfeld
- Molecular Parasitology, Institute of Biology/Faculty for Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany.,Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Josephine Grützke
- Molecular Parasitology, Institute of Biology/Faculty for Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany.,Department of Biological Safety, Federal Institute for Risk Assessment, Berlin, Germany
| | - Alyssa Ingmundson
- Molecular Parasitology, Institute of Biology/Faculty for Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Katja Müller
- Molecular Parasitology, Institute of Biology/Faculty for Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Kai Matuschewski
- Molecular Parasitology, Institute of Biology/Faculty for Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
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15
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Daniyan MO. Heat Shock Proteins as Targets for Novel Antimalarial Drug Discovery. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1340:205-236. [PMID: 34569027 DOI: 10.1007/978-3-030-78397-6_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Plasmodium falciparum, the parasitic agent that is responsible for a severe and dangerous form of human malaria, has a history of long years of cohabitation with human beings with attendant negative consequences. While there have been some gains in the fight against malaria through the application of various control measures and the use of chemotherapeutic agents, and despite the global decline in malaria cases and associated deaths, the continual search for new and effective therapeutic agents is key to achieving sustainable development goals. An important parasite survival strategy, which is also of serious concern to the scientific community, is the rate at which the parasites continually develop resistance to drugs. Among the key players in the parasite's ability to develop resistance, maintain cellular integrity, and survives within an unusual environment of the red blood cells are the molecular chaperones of the heat shock proteins (HSP) family. HSPs constitute a novel avenue for antimalarial drug discovery and by exploring their ubiquitous nature and multifunctional activities, they may be suitable targets for the discovery of multi-targets antimalarial drugs, needed to fight incessant drug resistance. In this chapter, features of selected families of plasmodial HSPs that can be exploited in drug discovery are presented. Also, known applications of HSPs in small molecule screening, their potential usefulness in high throughput drug screening, as well as possible challenges are highlighted.
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Affiliation(s)
- Michael Oluwatoyin Daniyan
- Department of Pharmacology, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria.
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16
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Protein Sorting in Plasmodium Falciparum. Life (Basel) 2021; 11:life11090937. [PMID: 34575086 PMCID: PMC8467625 DOI: 10.3390/life11090937] [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: 06/30/2021] [Revised: 09/04/2021] [Accepted: 09/04/2021] [Indexed: 11/23/2022] Open
Abstract
Plasmodium falciparum is a unicellular eukaryote with a very polarized secretory system composed of micronemes rhoptries and dense granules that are required for host cell invasion. P. falciparum, like its relative T. gondii, uses the endolysosomal system to produce the secretory organelles and to ingest host cell proteins. The parasite also has an apicoplast, a secondary endosymbiotic organelle, which depends on vesicular trafficking for appropriate incorporation of nuclear-encoded proteins into the apicoplast. Recently, the central molecules responsible for sorting and trafficking in P. falciparum and T. gondii have been characterized. From these studies, it is now evident that P. falciparum has repurposed the molecules of the endosomal system to the secretory pathway. Additionally, the sorting and vesicular trafficking mechanism seem to be conserved among apicomplexans. This review described the most recent findings on the molecular mechanisms of protein sorting and vesicular trafficking in P. falciparum and revealed that P. falciparum has an amazing secretory machinery that has been cleverly modified to its intracellular lifestyle.
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Ndwiga L, Osoti V, Ochwedo KO, Wamae K, Bejon P, Rayner JC, Githinji G, Ochola-Oyier LI. The Plasmodium falciparum Rh5 invasion protein complex reveals an excess of rare variant mutations. Malar J 2021; 20:278. [PMID: 34162366 PMCID: PMC8220363 DOI: 10.1186/s12936-021-03815-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 06/12/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The invasion of the red blood cells by Plasmodium falciparum merozoites involves the interplay of several proteins that are also targets for vaccine development. The proteins PfRh5-PfRipr-PfCyRPA-Pfp113 assemble into a complex at the apical end of the merozoite and are together essential for erythrocyte invasion. They have also been shown to induce neutralizing antibodies and appear to be less polymorphic than other invasion-associated proteins, making them high priority blood-stage vaccine candidates. Using available whole genome sequencing data (WGS) and new capillary sequencing data (CS), this study describes the genetic polymorphism in the Rh5 complex in P. falciparum isolates obtained from Kilifi, Kenya. METHODS 162 samples collected in 2013 and 2014 were genotyped by capillary sequencing (CS) and re-analysed WGS from 68 culture-adapted P. falciparum samples obtained from a drug trial conducted from 2005 to 2007. The frequency of polymorphisms in the merozoite invasion proteins, PfRh5, PfRipr, PfCyRPA and PfP113 were examined and where possible polymorphisms co-occurring in the same isolates. RESULTS From a total 70 variants, including 2 indels, 19 SNPs [27.1%] were identified by both CS and WGS, while an additional 15 [21.4%] and 36 [51.4%] SNPs were identified only by either CS or WGS, respectively. All the SNPs identified by CS were non-synonymous, whereas WGS identified 8 synonymous and 47 non-synonymous SNPs. CS identified indels in repeat regions in the p113 gene in codons 275 and 859 that were not identified in the WGS data. The minor allele frequencies of the SNPs ranged between 0.7 and 34.9% for WGS and 1.1-29.6% for CS. Collectively, 12 high frequency SNPs (> 5%) were identified: four in Rh5 codon 147, 148, 203 and 429, two in p113 at codons 7 and 267 and six in Ripr codons 190, 259, 524, 985, 1003 and 1039. CONCLUSION This study reveals that the majority of the polymorphisms are rare variants and confirms a low level of genetic polymorphisms in all proteins within the Rh5 complex.
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Affiliation(s)
- Leonard Ndwiga
- KEMRI-Wellcome Trust Research Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Victor Osoti
- KEMRI-Wellcome Trust Research Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Kevin Omondi Ochwedo
- Centre for Biotechnology and Bioinformatics, University of Nairobi, Nairobi, Kenya
| | - Kevin Wamae
- KEMRI-Wellcome Trust Research Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, P.O. Box 230, Kilifi, 80108, Kenya
- Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK
| | - Julian C Rayner
- Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge, CB2 0XY, UK
| | - George Githinji
- KEMRI-Wellcome Trust Research Programme, P.O. Box 230, Kilifi, 80108, Kenya
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Jonsdottir TK, Gabriela M, Crabb BS, F de Koning-Ward T, Gilson PR. Defining the Essential Exportome of the Malaria Parasite. Trends Parasitol 2021; 37:664-675. [PMID: 33985912 DOI: 10.1016/j.pt.2021.04.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/15/2021] [Accepted: 04/15/2021] [Indexed: 02/06/2023]
Abstract
To survive inside red blood cells (RBCs), malaria parasites export many proteins to alter their host cell's physiological properties. Although most proteins of this exportome are involved in immune avoidance or in the trafficking of exported proteins to the host membrane, about 20% are essential for parasite survival in culture but little is known about their biological functions. Here, we have combined information from large-scale genetic screens and targeted gene-disruption studies to tabulate all currently known Plasmodium falciparum exported proteins according to their likelihood of being essential. We also discuss the essential functional pathways that exported proteins might be involved in to help direct research efforts towards a more comprehensive understanding of host-cell remodelling.
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Affiliation(s)
- Thorey K Jonsdottir
- Burnet Institute, Melbourne, Victoria 3004, Australia; Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Mikha Gabriela
- Burnet Institute, Melbourne, Victoria 3004, Australia; School of Medicine, Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Brendan S Crabb
- Burnet Institute, Melbourne, Victoria 3004, Australia; Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria 3010, Australia
| | | | - Paul R Gilson
- Burnet Institute, Melbourne, Victoria 3004, Australia.
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Miyazaki S, Chitama BYA, Kagaya W, Lucky AB, Zhu X, Yahata K, Morita M, Takashima E, Tsuboi T, Kaneko O. Plasmodium falciparum SURFIN 4.1 forms an intermediate complex with PTEX components and Pf113 during export to the red blood cell. Parasitol Int 2021; 83:102358. [PMID: 33901679 DOI: 10.1016/j.parint.2021.102358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/08/2021] [Accepted: 04/14/2021] [Indexed: 02/04/2023]
Abstract
Plasmodium falciparum malaria parasites export several hundred proteins to the cytoplasm of infected red blood cells (RBCs) to modify the cell environment suitable for their growth. A Plasmodium translocon of exported proteins (PTEX) is necessary for both soluble and integral membrane proteins to cross the parasitophorous vacuole (PV) membrane surrounding the parasite inside the RBC. However, the molecular composition of the translocation complex for integral membrane proteins is not fully characterized, especially at the parasite plasma membrane. To examine the translocation complex, here we used mini-SURFIN4.1, consisting of a short N-terminal region, a transmembrane region, and a cytoplasmic region of an exported integral membrane protein SURFIN4.1. We found that mini-SURFIN4.1 forms a translocation intermediate complex with core PTEX components, EXP2, HSP101, and PTEX150. We also found that several proteins are exposed to the PV space, including Pf113, an uncharacterized PTEX-associated protein. We determined that Pf113 localizes in dense granules at the merozoite stage and on the parasite periphery after RBC invasion. Using an inducible translocon-clogged mini-SURFIN4.1, we found that a stable translocation intermediate complex forms at the parasite plasma membrane and contains EXP2 and a processed form of Pf113. These results suggest a potential role of Pf113 for the translocation step of mini-SURFIN4.1, providing further insights into the translocation mechanisms for parasite integral membrane proteins.
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Affiliation(s)
- Shinya Miyazaki
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Ben-Yeddy Abel Chitama
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Infectious Diseases, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Wataru Kagaya
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan; Department of Environmental Parasitology, Graduate School of Tokyo Medical and Dental University, Tokyo, Japan
| | - Amuza Byaruhanga Lucky
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Infectious Diseases, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Xiaotong Zhu
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Kazuhide Yahata
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Masayuki Morita
- Division of Malaria Research, Proteo-Science Center, Ehime University, Ehime, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Ehime, Japan
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Ehime, Japan
| | - Osamu Kaneko
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Infectious Diseases, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
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Abstract
Obligate intracellular malaria parasites reside within a vacuolar compartment generated during invasion which is the principal interface between pathogen and host. To subvert their host cell and support their metabolism, these parasites coordinate a range of transport activities at this membrane interface that are critically important to parasite survival and virulence, including nutrient import, waste efflux, effector protein export, and uptake of host cell cytosol. Here, we review our current understanding of the transport mechanisms acting at the malaria parasite vacuole during the blood and liver-stages of development with a particular focus on recent advances in our understanding of effector protein translocation into the host cell by the Plasmodium Translocon of EXported proteins (PTEX) and small molecule transport by the PTEX membrane-spanning pore EXP2. Comparison to Toxoplasma gondii and other related apicomplexans is provided to highlight how similar and divergent mechanisms are employed to fulfill analogous transport activities.
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Affiliation(s)
- Josh R. Beck
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Chi-Min Ho
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
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21
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Dousti M, Manzano-Román R, Rashidi S, Barzegar G, Ahmadpour NB, Mohammadi A, Hatam G. A proteomic glimpse into the effect of antimalarial drugs on Plasmodium falciparum proteome towards highlighting possible therapeutic targets. Pathog Dis 2021; 79:ftaa071. [PMID: 33202000 DOI: 10.1093/femspd/ftaa071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 11/13/2020] [Indexed: 02/07/2023] Open
Abstract
There is no effective vaccine against malaria; therefore, chemotherapy is to date the only choice to fight against this infectious disease. However, there is growing evidences of drug-resistance mechanisms in malaria treatments. Therefore, the identification of new drug targets is an urgent need for the clinical management of the disease. Proteomic approaches offer the chance of determining the effects of antimalarial drugs on the proteome of Plasmodium parasites. Accordingly, we reviewed the effects of antimalarial drugs on the Plasmodium falciparum proteome pointing out the relevance of several proteins as possible drug targets in malaria treatment. In addition, some of the P. falciparum stage-specific altered proteins and parasite-host interactions might play important roles in pathogenicity, survival, invasion and metabolic pathways and thus serve as potential sources of drug targets. In this review, we have identified several proteins, including thioredoxin reductase, helicases, peptidyl-prolyl cis-trans isomerase, endoplasmic reticulum-resident calcium-binding protein, choline/ethanolamine phosphotransferase, purine nucleoside phosphorylase, apical membrane antigen 1, glutamate dehydrogenase, hypoxanthine guanine phosphoribosyl transferase, heat shock protein 70x, knob-associated histidine-rich protein and erythrocyte membrane protein 1, as promising antimalarial drugs targets. Overall, proteomic approaches are able to partially facilitate finding possible drug targets. However, the integration of other 'omics' and specific pharmaceutical techniques with proteomics may increase the therapeutic properties of the critical proteins identified in the P. falciparum proteome.
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Affiliation(s)
- Majid Dousti
- Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Raúl Manzano-Román
- Proteomics Unit, Cancer Research Centre (IBMCC/CSIC/USAL/IBSAL), 37007, Salamanca, Spain
| | - Sajad Rashidi
- Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Gholamreza Barzegar
- Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Alireza Mohammadi
- Department of Disease Control, Komijan Treatment and Health Network, Arak University of Medical Science, Iran
| | - Gholamreza Hatam
- Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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22
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Role of the J Domain Protein Family in the Survival and Pathogenesis of Plasmodium falciparum. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1340:97-123. [PMID: 34569022 DOI: 10.1007/978-3-030-78397-6_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Plasmodium falciparum has dedicated an unusually large proportion of its genome to molecular chaperones (2% of all genes), with the heat shock protein 40 (Hsp40) family (now called J domain proteins, JDPs) exhibiting evolutionary radiation into 49 members. A large number of the P. falciparum JDPs (PfJDPs) are predicted to be exported, with certain members shown experimentally to be present in the erythrocyte cytosol (PFA0660w and PFE0055c) or erythrocyte membrane (ring-infected erythrocyte surface antigen, RESA). PFA0660w and PFE0055c are associated with an exported plasmodial Hsp70 (PfHsp70-x) within novel mobile structures called J-dots, which have been proposed to be dedicated to the trafficking of key membrane proteins such as erythrocyte membrane protein 1 (PfEMP1). Well over half of the PfJDPs appear to be essential, including the J-dot PfJDP, PFE0055c, while others have been found to be required for growth under febrile conditions (e.g. PFA0110w, the ring-infected erythrocyte surface antigen protein [RESA]) or involved in pathogenesis (e.g. PF10_0381 has been shown to be important for protrusions of the infected red blood cell membrane, the so-called knobs). Here we review what is known about those PfJDPs that have been well characterised, and may be directly or indirectly involved in the survival and pathogenesis of the malaria parasite.
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Shonhai A, Blatch GL. Heat Shock Proteins of Malaria: Highlights and Future Prospects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1340:237-246. [PMID: 34569028 DOI: 10.1007/978-3-030-78397-6_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The deadliest malaria parasite of humans, Plasmodium falciparum, is an obligate parasite that has had to develop mechanisms for survival under the unfavourable conditions it confronts within host cells. The chapters in the book "Heat Shock Proteins of Malaria" provide a critique of the evidence that heat shock proteins (Hsps) play a key role in the survival of P. falciparum in host cells. The role of the plasmodial Hsp arsenal is not limited to the protection of the parasite cell (largely through their role as molecular chaperones), as some of these proteins also promote the pathological development of malaria. This is largely due to the export of a large number of these proteins into the infected erythrocyte cytosol. Although P. falciparum erythrocyte membrane protein 1 (PfEMP1) is the main virulence factor for the malaria parasite, some of the exported plasmodial Hsps appear to augment parasite virulence. While this book largely delves into experimentally validated information on the role of Hsps in the development and pathogenicity of malaria, some of the information is based on hypotheses yet to be fully tested. Therefore, here we highlight what we know to be definite roles of plasmodial Hsps. Furthermore, we distill information that could provide practical insights on the options available for future research directions, including interventions against malaria that may target the role of Hsps in the development of the disease.
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Affiliation(s)
- Addmore Shonhai
- Department of Biochemistry, University of Venda, Thohoyandou, South Africa.
| | - Gregory L Blatch
- The Vice Chancellery, The University of Notre Dame Australia, Fremantle, WA, Australia. .,Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa. .,The Institute of Immunology and Infectious Diseases, Murdoch University, Murdoch, WA, Australia. .,Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates.
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PV1 Protein from Plasmodium falciparum Exhibits Chaperone-Like Functions and Cooperates with Hsp100s. Int J Mol Sci 2020; 21:ijms21228616. [PMID: 33207549 PMCID: PMC7697860 DOI: 10.3390/ijms21228616] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 01/17/2023] Open
Abstract
Plasmodium falciparum parasitophorous vacuolar protein 1 (PfPV1), a protein unique to malaria parasites, is localized in the parasitophorous vacuolar (PV) and is essential for parasite growth. Previous studies suggested that PfPV1 cooperates with the Plasmodium translocon of exported proteins (PTEX) complex to export various proteins from the PV. However, the structure and function of PfPV1 have not been determined in detail. In this study, we undertook the expression, purification, and characterization of PfPV1. The tetramer appears to be the structural unit of PfPV1. The activity of PfPV1 appears to be similar to that of molecular chaperones, and it may interact with various proteins. PfPV1 could substitute CtHsp40 in the CtHsp104, CtHsp70, and CtHsp40 protein disaggregation systems. Based on these results, we propose a model in which PfPV1 captures various PV proteins and delivers them to PTEX through a specific interaction with HSP101.
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The Structure of the Cysteine-Rich Domain of Plasmodium falciparum P113 Identifies the Location of the RH5 Binding Site. mBio 2020; 11:mBio.01566-20. [PMID: 32900802 PMCID: PMC7482062 DOI: 10.1128/mbio.01566-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Malaria is a deadly infectious disease primarily caused by the parasite Plasmodium falciparum. It remains a major global health problem, and there is no highly effective vaccine. A parasite protein called RH5 is centrally involved in the invasion of host red blood cells, making it—and the other parasite proteins it interacts with—promising vaccine targets. We recently identified a protein called P113 that binds RH5, suggesting that it anchors RH5 to the parasite surface. In this paper, we use structural biology to locate and characterize the RH5 binding region on P113. These findings will be important to guide the development of new antimalarial vaccines to ultimately prevent this disease, which affects some of the poorest people on the planet. Plasmodium falciparum RH5 is a secreted parasite ligand that is essential for erythrocyte invasion through direct interaction with the host erythrocyte receptor basigin. RH5 forms a tripartite complex with two other secreted parasite proteins, CyRPA and RIPR, and is tethered to the surface of the parasite through membrane-anchored P113. Antibodies against RH5, CyRPA, and RIPR can inhibit parasite invasion, suggesting that vaccines containing these three components have the potential to prevent blood-stage malaria. To further explore the role of the P113-RH5 interaction, we selected monoclonal antibodies against P113 that were either inhibitory or noninhibitory for RH5 binding. Using a Fab fragment as a crystallization chaperone, we determined the crystal structure of the RH5 binding region of P113 and showed that it is composed of two domains with structural similarities to rhamnose-binding lectins. We identified the RH5 binding site on P113 by using a combination of hydrogen-deuterium exchange mass spectrometry and site-directed mutagenesis. We found that a monoclonal antibody to P113 that bound to this interface and inhibited the RH5-P113 interaction did not inhibit parasite blood-stage growth. These findings provide further structural information on the protein interactions of RH5 and will be helpful in guiding the development of blood-stage malaria vaccines that target RH5.
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El Chamy Maluf S, Icimoto MY, Melo PMS, Budu A, Coimbra R, Gazarini ML, Carmona AK. Human plasma plasminogen internalization route in Plasmodium falciparum-infected erythrocytes. Malar J 2020; 19:302. [PMID: 32847585 PMCID: PMC7449074 DOI: 10.1186/s12936-020-03377-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/14/2020] [Indexed: 02/03/2023] Open
Abstract
Background The intra-erythrocytic development of the malaria parasite Plasmodium falciparum depends on the uptake of a number of essential nutrients from the host cell and blood plasma. It is widely recognized that the parasite imports low molecular weight solutes from the plasma and the consumption of these nutrients by P. falciparum has been extensively analysed. However, although it was already shown that the parasite also imports functional proteins from the vertebrate host, the internalization route through the different infected erythrocyte membranes has not yet been elucidated. In order to further understand the uptake mechanism, the study examined the trafficking of human plasminogen from the extracellular medium into P. falciparum-infected red blood cells. Methods Plasmodium falciparum clone 3D7 was cultured in standard HEPES-buffered RPMI 1640 medium supplemented with 0.5% AlbuMAX. Exogenous human plasminogen was added to the P. falciparum culture and the uptake of this protein by the parasites was analysed by electron microscopy and Western blotting. Immunoprecipitation and mass spectrometry were performed to investigate possible protein interactions that may assist plasminogen import into infected erythrocytes. The effect of pharmacological inhibitors of different cellular physiological processes in plasminogen uptake was also tested. Results It was observed that plasminogen was selectively internalized by P. falciparum-infected erythrocytes, with localization in plasma membrane erythrocyte and parasite’s cytosol. The protein was not detected in parasitic food vacuole and haemoglobin-containing vesicles. Furthermore, in erythrocyte cytoplasm, plasminogen was associated with the parasite-derived membranous structures tubovesicular network (TVN) and Maurer’s clefts. Several proteins were identified in immunoprecipitation assay and may be involved in the delivery of plasminogen across the P. falciparum multiple compartments. Conclusion The findings here reported reveal new features regarding the acquisition of plasma proteins of the host by P. falciparum-infected erythrocytes, a mechanism that involves the exomembrane system, which is distinct from the haemoglobin uptake, clarifying a route that may be potentially targeted for inhibition studies.
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Affiliation(s)
- Sarah El Chamy Maluf
- Departamento de Biofísica, Universidade Federal de São Paulo, Rua Pedro de Toledo 669, 7°andar, Vila Clementino, São Paulo, 04039032, Brazil
| | - Marcelo Yudi Icimoto
- Departamento de Biofísica, Universidade Federal de São Paulo, Rua Pedro de Toledo 669, 7°andar, Vila Clementino, São Paulo, 04039032, Brazil
| | - Pollyana Maria Saud Melo
- Departamento de Biofísica, Universidade Federal de São Paulo, Rua Pedro de Toledo 669, 7°andar, Vila Clementino, São Paulo, 04039032, Brazil
| | - Alexandre Budu
- Departamento de Biofísica, Universidade Federal de São Paulo, Rua Pedro de Toledo 669, 7°andar, Vila Clementino, São Paulo, 04039032, Brazil
| | - Rita Coimbra
- Centro de Microscopia Eletrônica (CEME), Universidade Federal de São Paulo, Rua Botucatu 862, Vila Clementino, São Paulo, Brazil
| | - Marcos Leoni Gazarini
- Departamento de Biociências, Universidade Federal de São Paulo, Rua Silva Jardim 136, Lab. 329, 3°andar, Vila Mathias, Santos, São Paulo, 11015020, Brazil.
| | - Adriana Karaoglanovic Carmona
- Departamento de Biofísica, Universidade Federal de São Paulo, Rua Pedro de Toledo 669, 7°andar, Vila Clementino, São Paulo, 04039032, Brazil.
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Crossing the Vacuolar Rubicon: Structural Insights into Effector Protein Trafficking in Apicomplexan Parasites. Microorganisms 2020; 8:microorganisms8060865. [PMID: 32521667 PMCID: PMC7355975 DOI: 10.3390/microorganisms8060865] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 12/13/2022] Open
Abstract
Apicomplexans form a large phylum of parasitic protozoa, including the genera Plasmodium, Toxoplasma, and Cryptosporidium, the causative agents of malaria, toxoplasmosis, and cryptosporidiosis, respectively. They cause diseases not only in humans but also in animals, with dramatic consequences in agriculture. Most apicomplexans are vacuole-dwelling and obligate intracellular parasites; as they invade the host cell, they become encased in a parasitophorous vacuole (PV) derived from the host cellular membrane. This creates a parasite-host interface that acts as a protective barrier but also constitutes an obstacle through which the pathogen must import nutrients, eliminate wastes, and eventually break free upon egress. Completion of the parasitic life cycle requires intense remodeling of the infected host cell. Host cell subversion is mediated by a subset of essential effector parasitic proteins and virulence factors actively trafficked across the PV membrane. In the malaria parasite Plasmodium, a unique and highly specialized ATP-driven vacuolar secretion system, the Plasmodium translocon of exported proteins (PTEX), transports effector proteins across the vacuolar membrane. Its core is composed of the three essential proteins EXP2, PTEX150, and HSP101, and is supplemented by the two auxiliary proteins TRX2 and PTEX88. Many but not all secreted malarial effector proteins contain a vacuolar trafficking signal or Plasmodium export element (PEXEL) that requires processing by an endoplasmic reticulum protease, plasmepsin V, for proper export. Because vacuolar parasitic protein export is essential to parasite survival and virulence, this pathway is a promising target for the development of novel antimalarial therapeutics. This review summarizes the current state of structural and mechanistic knowledge on the Plasmodium parasitic vacuolar secretion and effector trafficking pathway, describing its most salient features and discussing the existing differences and commonalities with the vacuolar effector translocation MYR machinery recently described in Toxoplasma and other apicomplexans of significance to medical and veterinary sciences.
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Ragotte RJ, Higgins MK, Draper SJ. The RH5-CyRPA-Ripr Complex as a Malaria Vaccine Target. Trends Parasitol 2020; 36:545-559. [PMID: 32359873 PMCID: PMC7246332 DOI: 10.1016/j.pt.2020.04.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/03/2020] [Accepted: 04/03/2020] [Indexed: 11/04/2022]
Abstract
Despite ongoing efforts, a highly effective vaccine against Plasmodium falciparum remains elusive. Vaccines targeting the pre-erythrocytic stages of the P. falciparum life cycle are the most advanced to date, affording moderate levels of efficacy in field trials. However, the discovery that the members of the merozoite PfRH5-PfCyRPA-PfRipr (RCR) complex are capable of inducing strain-transcendent neutralizing antibodies has renewed enthusiasm for the possibility of preventing disease by targeting the parasite during the blood stage of infection. With Phase I/II clinical trials now underway using first-generation vaccines against PfRH5, and more on the horizon for PfCyRPA and PfRipr, this review explores the rationale and future potential of the RCR complex as a P. falciparum vaccine target.
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Affiliation(s)
- Robert J Ragotte
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK.
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Simon J Draper
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK.
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Florentin A, Cobb DW, Kudyba HM, Muralidharan V. Directing traffic: Chaperone-mediated protein transport in malaria parasites. Cell Microbiol 2020; 22:e13215. [PMID: 32388921 PMCID: PMC7282954 DOI: 10.1111/cmi.13215] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/12/2020] [Accepted: 04/14/2020] [Indexed: 12/16/2022]
Abstract
The ability of eukaryotic parasites from the phylum Apicomplexa to cause devastating diseases is predicated upon their ability to maintain faithful and precise protein trafficking mechanisms. Their parasitic life cycle depends on the trafficking of effector proteins to the infected host cell, transport of proteins to several critical organelles required for survival, as well as transport of parasite and host proteins to the digestive organelles to generate the building blocks for parasite growth. Several recent studies have shed light on the molecular mechanisms parasites utilise to transform the infected host cells, transport proteins to essential metabolic organelles and for biogenesis of organelles required for continuation of their life cycle. Here, we review key pathways of protein transport originating and branching from the endoplasmic reticulum, focusing on the essential roles of chaperones in these processes. Further, we highlight key gaps in our knowledge that prevents us from building a holistic view of protein trafficking in these deadly human pathogens.
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Affiliation(s)
- Anat Florentin
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - David W Cobb
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Heather M Kudyba
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Vasant Muralidharan
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
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The parasitophorous vacuole of the blood-stage malaria parasite. Nat Rev Microbiol 2020; 18:379-391. [PMID: 31980807 DOI: 10.1038/s41579-019-0321-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2019] [Indexed: 12/31/2022]
Abstract
The pathology of malaria is caused by infection of red blood cells with unicellular Plasmodium parasites. During blood-stage development, the parasite replicates within a membrane-bound parasitophorous vacuole. A central nexus for host-parasite interactions, this unique parasite shelter functions in nutrient acquisition, subcompartmentalization and the export of virulence factors, making its functional molecules attractive targets for the development of novel intervention strategies to combat the devastating impact of malaria. In this Review, we explore the origin, development, molecular composition and functions of the parasitophorous vacuole of Plasmodium blood stages. We also discuss the relevance of the malaria parasite's intravacuolar lifestyle for successful erythrocyte infection and provide perspectives for future research directions in parasitophorous vacuole biology.
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31
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Sexton AE, Doerig C, Creek DJ, Carvalho TG. Post-Genomic Approaches to Understanding Malaria Parasite Biology: Linking Genes to Biological Functions. ACS Infect Dis 2019; 5:1269-1278. [PMID: 31243988 DOI: 10.1021/acsinfecdis.9b00093] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Plasmodium species are evolutionarily distant from model eukaryotes, and as a consequence they exhibit many non-canonical cellular processes. In the post-genomic era, functional "omics" disciplines (transcriptomics, proteomics, and metabolomics) have accelerated our understanding of unique aspects of the biology of malaria parasites. Functional "omics" tools, in combination with genetic manipulations, have offered new opportunities to investigate the function of previously uncharacterized genes. Knowledge of basic parasite biology is fundamental to understanding drug modes of action, mechanisms of drug resistance, and relevance of vaccine candidates. This Perspective highlights recent "omics"-based discoveries in basic biology and gene function of the most virulent human malaria parasite, Plasmodium falciparum.
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Affiliation(s)
- Anna E. Sexton
- Drug Delivery Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Christian Doerig
- Centre for Chronic, Inflammatory and Infectious Diseases, Biomedical Sciences Cluster, School of Health and Biomedical Sciences, RMIT University, 264 Plenty Road, Bundoora, VIC 3083, Australia
| | - Darren J. Creek
- Drug Delivery Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Teresa G. Carvalho
- Molecular Parasitology Laboratory, Department of Physiology, Anatomy and Microbiology, La Trobe University, Kingsbury Drive, Bundoora, VIC 3086, Australia
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Healer J, Wong W, Thompson JK, He W, Birkinshaw RW, Miura K, Long CA, Soroka V, Søgaard TMM, Jørgensen T, de Jongh WA, Weir C, Svahn E, Czabotar PE, Tham W, Mueller I, Barlow PN, Cowman AF. Neutralising antibodies block the function of Rh5/Ripr/CyRPA complex during invasion of Plasmodium falciparum into human erythrocytes. Cell Microbiol 2019; 21:e13030. [PMID: 30965383 PMCID: PMC6594224 DOI: 10.1111/cmi.13030] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/04/2019] [Accepted: 03/11/2019] [Indexed: 01/19/2023]
Abstract
An effective vaccine is a priority for malaria control and elimination. The leading candidate in the Plasmodium falciparum blood stage is PfRh5. PfRh5 assembles into trimeric complex with PfRipr and PfCyRPA in the parasite, and this complex is essential for erythrocyte invasion. In this study, we show that antibodies specific for PfRh5 and PfCyRPA prevent trimeric complex formation. We identify the EGF-7 domain on PfRipr as a neutralising epitope and demonstrate that antibodies against this region act downstream of complex formation to prevent merozoite invasion. Antibodies against the C-terminal region of PfRipr were more inhibitory than those against either PfRh5 or PfCyRPA alone, and a combination of antibodies against PfCyRPA and PfRipr acted synergistically to reduce invasion. This study supports prioritisation of PfRipr for development as part of a next-generation antimalarial vaccine.
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Affiliation(s)
- Julie Healer
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Wilson Wong
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Jennifer K. Thompson
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
| | - Wengqiang He
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Richard W. Birkinshaw
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector ResearchNational Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesdaMarylandUSA
| | - Carol A. Long
- Laboratory of Malaria and Vector ResearchNational Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesdaMarylandUSA
| | | | | | | | | | - Christopher Weir
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
- Schools of Chemistry and Biological SciencesUniversity of EdinburghEdinburghScotland, UK
| | - Ella Svahn
- Schools of Chemistry and Biological SciencesUniversity of EdinburghEdinburghScotland, UK
| | - Peter E. Czabotar
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Wai‐Hong Tham
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Ivo Mueller
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Paul N. Barlow
- Schools of Chemistry and Biological SciencesUniversity of EdinburghEdinburghScotland, UK
| | - Alan F. Cowman
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
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Illingworth JJ, Alanine DG, Brown R, Marshall JM, Bartlett HE, Silk SE, Labbé GM, Quinkert D, Cho JS, Wendler JP, Pattinson DJ, Barfod L, Douglas AD, Shea MW, Wright KE, de Cassan SC, Higgins MK, Draper SJ. Functional Comparison of Blood-Stage Plasmodium falciparum Malaria Vaccine Candidate Antigens. Front Immunol 2019; 10:1254. [PMID: 31214195 PMCID: PMC6558156 DOI: 10.3389/fimmu.2019.01254] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 05/17/2019] [Indexed: 12/22/2022] Open
Abstract
The malaria genome encodes over 5,000 proteins and many of these have also been proposed to be potential vaccine candidates, although few of these have been tested clinically. RH5 is one of the leading blood-stage Plasmodium falciparum malaria vaccine antigens and Phase I/II clinical trials of vaccines containing this antigen are currently underway. Its likely mechanism of action is to elicit antibodies that can neutralize merozoites by blocking their invasion of red blood cells (RBC). However, many other antigens could also elicit neutralizing antibodies against the merozoite, and most of these have never been compared directly to RH5. The objective of this study was to compare a range of blood-stage antigens to RH5, to identify any antigens that outperform or synergize with anti-RH5 antibodies. We selected 55 gene products, covering 15 candidate antigens that have been described in the literature and 40 genes selected on the basis of bioinformatics functional prediction. We were able to make 20 protein-in-adjuvant vaccines from the original selection. Of these, S-antigen and CyRPA robustly elicited antibodies with neutralizing properties. Anti-CyRPA IgG generally showed additive GIA with anti-RH5 IgG, although high levels of anti-CyRPA-specific rabbit polyclonal IgG were required to achieve 50% GIA. Our data suggest that further vaccine antigen screening efforts are required to identify a second merozoite target with similar antibody-susceptibility to RH5.
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Affiliation(s)
| | | | - Rebecca Brown
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | | | - Sarah E Silk
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Doris Quinkert
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Jee Sun Cho
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Jason P Wendler
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Lea Barfod
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Michael W Shea
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Katherine E Wright
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | | | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Simon J Draper
- Jenner Institute, University of Oxford, Oxford, United Kingdom
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34
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Matthews KM, Kalanon M, de Koning-Ward TF. Uncoupling the Threading and Unfoldase Actions of Plasmodium HSP101 Reveals Differences in Export between Soluble and Insoluble Proteins. mBio 2019; 10:e01106-19. [PMID: 31164473 PMCID: PMC6550532 DOI: 10.1128/mbio.01106-19] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 05/06/2019] [Indexed: 12/02/2022] Open
Abstract
Plasmodium parasites must export proteins into their erythrocytic host to survive. Exported proteins must cross the parasite plasma membrane (PPM) and the parasitophorous vacuolar membrane (PVM) encasing the parasite to access the host cell. Crossing the PVM requires protein unfolding and passage through a translocon, the Plasmodium translocon of exported proteins (PTEX). In this study, we provide the first direct evidence that heat shock protein 101 (HSP101), a core component of PTEX, unfolds proteins for translocation across the PVM by creating transgenic Plasmodium parasites in which the unfoldase and translocation functions of HSP101 have become uncoupled. Strikingly, while these parasites could export native proteins, they were unable to translocate soluble, tightly folded reporter proteins bearing the Plasmodium export element (PEXEL) across the PVM into host erythrocytes under the same conditions. In contrast, an identical PEXEL reporter protein but harboring a transmembrane domain could be exported, suggesting that a prior unfolding step occurs at the PPM. Together, these results demonstrate that the export of parasite proteins is dependent on how these proteins are presented to the secretory pathway before they reach PTEX as well as their folded status. Accordingly, only tightly folded soluble proteins secreted into the vacuolar space and not proteins containing transmembrane domains or the majority of erythrocyte-stage exported proteins have an absolute requirement for the full unfoldase activity of HSP101 to be exported.IMPORTANCE The Plasmodium parasites that cause malaria export hundreds of proteins into their host red blood cell (RBC). These exported proteins drastically alter the structural and functional properties of the RBC and play critical roles in parasite virulence and survival. To access the RBC cytoplasm, parasite proteins must pass through the Plasmodium translocon of exported proteins (PTEX) located at the membrane interfacing the parasite and host cell. Our data provide evidence that HSP101, a component of PTEX, serves to unfold protein cargo requiring translocation. We also reveal that addition of a transmembrane domain to soluble cargo influences its ability to be translocated by parasites in which the HSP101 motor and unfolding activities have become uncoupled. Therefore, we propose that proteins with transmembrane domains use an alternative unfolding pathway prior to PTEX to facilitate export.
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Affiliation(s)
| | - Ming Kalanon
- School of Medicine, Deakin University, Waurn Ponds, Victoria, Australia
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35
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Matthews KM, Pitman EL, de Koning-Ward TF. Illuminating how malaria parasites export proteins into host erythrocytes. Cell Microbiol 2019; 21:e13009. [PMID: 30656810 DOI: 10.1111/cmi.13009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/06/2018] [Accepted: 12/17/2018] [Indexed: 12/11/2022]
Abstract
Plasmodium parasites that cause the disease malaria have developed an elaborate trafficking pathway to facilitate the export of hundreds of effector proteins into their host cell, the erythrocyte. In this review, we outline how certain effector proteins contribute to parasite survival, virulence, and immune evasion. We also highlight how parasite proteins destined for export are recognised at the endoplasmic reticulum to facilitate entry into the export pathway and how the effector proteins are able to transverse the bounding parasitophorous vaculoar membrane via the Plasmodium translocon of exported proteins to gain access to the host cell. Some of the gaps in our understanding of the export pathway are also presented. Finally, we examine the degree of conservation of some of the key components of the Plasmodium export pathway in closely related apicomplexan parasites, which may provide insight into how the diverse apicomplexan parasites have adapted to survival pressures encountered within their respective host cells.
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Affiliation(s)
| | - Ethan L Pitman
- School of Medicine, Deakin University, Waurn Ponds, Victoria, Australia
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36
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Engel JA, Norris EL, Gilson P, Przyborski J, Shonhai A, Blatch GL, Skinner-Adams TS, Gorman J, Headlam M, Andrews KT. Proteomic analysis of Plasmodium falciparum histone deacetylase 1 complex proteins. Exp Parasitol 2019; 198:7-16. [PMID: 30682336 DOI: 10.1016/j.exppara.2019.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/01/2018] [Accepted: 01/20/2019] [Indexed: 01/12/2023]
Abstract
Plasmodium falciparum histone deacetylases (PfHDACs) are an important class of epigenetic regulators that alter protein lysine acetylation, contributing to regulation of gene expression and normal parasite growth and development. PfHDACs are therefore under investigation as drug targets for malaria. Despite this, our understanding of the biological roles of these enzymes is only just beginning to emerge. In higher eukaryotes, HDACs function as part of multi-protein complexes and act on both histone and non-histone substrates. Here, we present a proteomics analysis of PfHDAC1 immunoprecipitates, identifying 26 putative P. falciparum complex proteins in trophozoite-stage asexual intraerythrocytic parasites. The co-migration of two of these (P. falciparum heat shock proteins 70-1 and 90) with PfHDAC1 was validated using Blue Native PAGE combined with Western blot. These data provide a snapshot of possible PfHDAC1 interactions and a starting point for future studies focused on elucidating the broader function of PfHDACs in Plasmodium parasites.
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Affiliation(s)
- Jessica A Engel
- Griffith Institute for Drug Discovery, Griffith University, Queensland, Australia
| | - Emma L Norris
- QIMR Berghofer Medical Research Institute, Queensland, Australia
| | - Paul Gilson
- Burnet Institute, Monash University, Victoria, Australia
| | - Jude Przyborski
- Centre of Infectious Diseases, Parasitology, University Hospital Heidelberg, Germany
| | - Addmore Shonhai
- Biochemistry Department, University of Venda, Thohoyandou, South Africa
| | - Gregory L Blatch
- The Vice Chancellery, The University of Notre Dame Australia, Fremantle, WA, Australia
| | - Tina S Skinner-Adams
- Griffith Institute for Drug Discovery, Griffith University, Queensland, Australia
| | - Jeffrey Gorman
- QIMR Berghofer Medical Research Institute, Queensland, Australia
| | | | - Katherine T Andrews
- Griffith Institute for Drug Discovery, Griffith University, Queensland, Australia.
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37
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Sanders PR, Dickerman BK, Charnaud SC, Ramsland PA, Crabb BS, Gilson PR. The N-terminus of EXP2 forms the membrane-associated pore of the protein exporting translocon PTEX in Plasmodium falciparum. J Biochem 2018; 165:239-248. [DOI: 10.1093/jb/mvy099] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/20/2018] [Indexed: 12/12/2022] Open
Affiliation(s)
| | | | | | - Paul A Ramsland
- Burnet Institute, Melbourne, VIC, Australia
- University of Melbourne, Melbourne, VIC, Australia
- RMIT University, Bundoora, VIC, Australia
- Monash University, Melbourne, VIC, Australia
| | - Brendan S Crabb
- Burnet Institute, Melbourne, VIC, Australia
- University of Melbourne, Melbourne, VIC, Australia
- Monash University, Melbourne, VIC, Australia
| | - Paul R Gilson
- Burnet Institute, Melbourne, VIC, Australia
- Monash University, Melbourne, VIC, Australia
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38
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Knockdown of the translocon protein EXP2 in Plasmodium falciparum reduces growth and protein export. PLoS One 2018; 13:e0204785. [PMID: 30439948 PMCID: PMC6237293 DOI: 10.1371/journal.pone.0204785] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/30/2018] [Indexed: 11/23/2022] Open
Abstract
Malaria parasites remodel their host erythrocytes to gain nutrients and avoid the immune system. Host erythrocytes are modified by hundreds of effector proteins exported from the parasite into the host cell. Protein export is mediated by the PTEX translocon comprising five core components of which EXP2 is considered to form the putative pore that spans the vacuole membrane enveloping the parasite within its erythrocyte. To explore the function and importance of EXP2 for parasite survival in the asexual blood stage of Plasmodium falciparum we inducibly knocked down the expression of EXP2. Reduction in EXP2 expression strongly reduced parasite growth proportional to the degree of protein knockdown and tended to stall development about half way through the asexual cell cycle. Once the knockdown inducer was removed and EXP2 expression restored, parasite growth recovered dependent upon the length and degree of knockdown. To establish EXP2 function and hence the basis for growth reduction, the trafficking of an exported protein was monitored following EXP2 knockdown. This resulted in severe attenuation of protein export and is consistent with EXP2, and PTEX in general, being the conduit for export of proteins into the host compartment.
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39
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Ho CM, Beck JR, Lai M, Cui Y, Goldberg DE, Egea PF, Zhou ZH. Malaria parasite translocon structure and mechanism of effector export. Nature 2018; 561:70-75. [PMID: 30150771 PMCID: PMC6555636 DOI: 10.1038/s41586-018-0469-4] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/19/2018] [Indexed: 12/18/2022]
Abstract
The putative Plasmodium translocon of exported proteins (PTEX) is essential for transport of malarial effector proteins across a parasite-encasing vacuolar membrane into host erythrocytes, but the mechanism of this process remains unknown. Here we show that PTEX is a bona fide translocon by determining structures of the PTEX core complex at near-atomic resolution using cryo-electron microscopy. We isolated the endogenous PTEX core complex containing EXP2, PTEX150 and HSP101 from Plasmodium falciparum in the 'engaged' and 'resetting' states of endogenous cargo translocation using epitope tags inserted using the CRISPR-Cas9 system. In the structures, EXP2 and PTEX150 interdigitate to form a static, funnel-shaped pseudo-seven-fold-symmetric protein-conducting channel spanning the vacuolar membrane. The spiral-shaped AAA+ HSP101 hexamer is tethered above this funnel, and undergoes pronounced compaction that allows three of six tyrosine-bearing pore loops lining the HSP101 channel to dissociate from the cargo, resetting the translocon for the next threading cycle. Our work reveals the mechanism of P. falciparum effector export, and will inform structure-based design of drugs targeting this unique translocon.
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Affiliation(s)
- Chi-Min Ho
- The Molecular Biology Institute, University of California, Los Angeles, CA, USA
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, CA, USA
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Josh R Beck
- Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Mason Lai
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, CA, USA
| | - Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Daniel E Goldberg
- Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Pascal F Egea
- The Molecular Biology Institute, University of California, Los Angeles, CA, USA.
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
| | - Z Hong Zhou
- The Molecular Biology Institute, University of California, Los Angeles, CA, USA.
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, CA, USA.
- California NanoSystems Institute, University of California, Los Angeles, CA, USA.
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40
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Charnaud SC, Jonsdottir TK, Sanders PR, Bullen HE, Dickerman BK, Kouskousis B, Palmer CS, Pietrzak HM, Laumaea AE, Erazo AB, McHugh E, Tilley L, Crabb BS, Gilson PR. Spatial organization of protein export in malaria parasite blood stages. Traffic 2018; 19:605-623. [DOI: 10.1111/tra.12577] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 04/21/2018] [Accepted: 04/24/2018] [Indexed: 12/29/2022]
Affiliation(s)
| | - Thorey K. Jonsdottir
- Burnet Institute; Melbourne Australia
- Peter Doherty Institute for Infection and Immunity, University of Melbourne; Melbourne Australia
| | | | | | | | - Betty Kouskousis
- Burnet Institute; Melbourne Australia
- Monash Micro Imaging, Monash University; Melbourne Australia
| | - Catherine S. Palmer
- Burnet Institute; Melbourne Australia
- Monash Micro Imaging, Monash University; Melbourne Australia
| | | | | | | | - Emma McHugh
- Department of Biochemistry and Molecular Biology, University of Melbourne; Melbourne Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, University of Melbourne; Melbourne Australia
| | - Brendan S. Crabb
- Burnet Institute; Melbourne Australia
- Peter Doherty Institute for Infection and Immunity, University of Melbourne; Melbourne Australia
- Department of Microbiology, Monash University; Melbourne Australia
| | - Paul R. Gilson
- Burnet Institute; Melbourne Australia
- Department of Microbiology, Monash University; Melbourne Australia
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41
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Chisholm SA, Kalanon M, Nebl T, Sanders PR, Matthews KM, Dickerman BK, Gilson PR, de Koning-Ward TF. The malaria PTEX component PTEX88 interacts most closely with HSP101 at the host-parasite interface. FEBS J 2018; 285:2037-2055. [PMID: 29637707 DOI: 10.1111/febs.14463] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 03/08/2018] [Accepted: 04/03/2018] [Indexed: 12/28/2022]
Abstract
The pathogenic nature of malaria infections is due in part to the export of hundreds of effector proteins that actively remodel the host erythrocyte. The Plasmodium translocon of exported proteins (PTEX) has been shown to facilitate the trafficking of proteins into the host cell, a process that is essential for the survival of the parasite. The role of the auxiliary PTEX component PTEX88 remains unclear, as previous attempts to elucidate its function through reverse genetic approaches showed that in contrast to the core components PTEX150 and HSP101, knockdown of PTEX88 did not give rise to an export phenotype. Here, we have used biochemical approaches to understand how PTEX88 assembles within the translocation machinery. Proteomic analysis of the PTEX88 interactome showed that PTEX88 interacts closely with HSP101 but has a weaker affinity with the other core constituents of PTEX. PTEX88 was also found to associate with other PV-resident proteins, including chaperones and members of the exported protein-interacting complex that interacts with the major virulence factor PfEMP1, the latter contributing to cytoadherence and parasite virulence. Despite being expressed for the duration of the blood-stage life cycle, PTEX88 was only discretely observed at the parasitophorous vacuole membrane during ring stages and could not always be detected in the major high molecular weight complex that contains the other core components of PTEX, suggesting that its interaction with the PTEX complex may be dynamic. Together, these data have enabled the generation of an updated model of PTEX that now includes how PTEX88 assembles within the complex.
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Affiliation(s)
| | - Ming Kalanon
- School of Medicine, Deakin University, Waurn Ponds, Australia
| | - Thomas Nebl
- The Walter and Eliza Hall Institute, Parkville, Australia
| | - Paul R Sanders
- Burnet Institute, Prahran, Australia.,Monash University, Melbourne, Australia
| | | | | | - Paul R Gilson
- Burnet Institute, Prahran, Australia.,Monash University, Melbourne, Australia
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42
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Naor A, Panas MW, Marino N, Coffey MJ, Tonkin CJ, Boothroyd JC. MYR1-Dependent Effectors Are the Major Drivers of a Host Cell's Early Response to Toxoplasma, Including Counteracting MYR1-Independent Effects. mBio 2018; 9:e02401-17. [PMID: 29615509 PMCID: PMC5885026 DOI: 10.1128/mbio.02401-17] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 03/07/2018] [Indexed: 01/08/2023] Open
Abstract
The obligate intracellular parasite Toxoplasma gondii controls its host cell from within the parasitophorous vacuole (PV) by using a number of diverse effector proteins, a subset of which require the aspartyl protease 5 enzyme (ASP5) and/or the recently discovered MYR1 protein to cross the PV membrane. To examine the impact these effectors have in the context of the entirety of the host response to Toxoplasma, we used RNA-Seq to analyze the transcriptome expression profiles of human foreskin fibroblasts infected with wild-type RH (RH-WT), RHΔmyr1, and RHΔasp5 tachyzoites. Interestingly, the majority of the differentially regulated genes responding to Toxoplasma infection are MYR1 dependent. A subset of MYR1 responses were ASP5 independent, and MYR1 function did not require ASP5 cleavage, suggesting the export of some effectors requires only MYR1. Gene set enrichment analysis of MYR1-dependent host responses suggests an upregulation of E2F transcription factors and the cell cycle and a downregulation related to interferon signaling, among numerous others. Most surprisingly, "hidden" responses arising in RHΔmyr1- but not RH-WT-infected host cells indicate counterbalancing actions of MYR1-dependent and -independent activities. The host genes and gene sets revealed here to be MYR1 dependent provide new insight into the parasite's ability to co-opt host cell functions.IMPORTANCEToxoplasma gondii is unique in its ability to successfully invade and replicate in a broad range of host species and cells within those hosts. The complex interplay of effector proteins exported by Toxoplasma is key to its success in co-opting the host cell to create a favorable replicative niche. Here we show that a majority of the transcriptomic effects in tachyzoite-infected cells depend on the activity of a novel translocation system involving MYR1 and that the effectors delivered by this system are part of an intricate interplay of activators and suppressors. Removal of all MYR1-dependent effectors reveals previously unknown activities that are masked or hidden by the action of these proteins.
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Affiliation(s)
- Adit Naor
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Michael W Panas
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Nicole Marino
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Michael J Coffey
- Division of Infection and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Christopher J Tonkin
- Division of Infection and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - John C Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
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Abstract
Plasmodium species cause malaria by proliferating in human erythrocytes. Invasion of immunologically privileged erythrocytes provides a relatively protective niche as well as access to a rich source of nutrients. Plasmodium spp. target erythrocytes of different ages, but share a common mechanism of invasion. Specific engagement of erythrocyte receptors defines target cell tropism, activating downstream events and resulting in the physical penetration of the erythrocyte, powered by the parasite's actinomyosin-based motor. Here we review the latest in our understanding of the molecular composition of this highly complex and fascinating biological process.
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44
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Morita M, Nagaoka H, Ntege EH, Kanoi BN, Ito D, Nakata T, Lee JW, Tokunaga K, Iimura T, Torii M, Tsuboi T, Takashima E. PV1, a novel Plasmodium falciparum merozoite dense granule protein, interacts with exported protein in infected erythrocytes. Sci Rep 2018; 8:3696. [PMID: 29487358 PMCID: PMC5829233 DOI: 10.1038/s41598-018-22026-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 02/07/2018] [Indexed: 01/09/2023] Open
Abstract
Upon invasion, Plasmodium falciparum exports hundreds of proteins across its surrounding parasitophorous vacuole membrane (PVM) to remodel the infected erythrocyte. Although this phenomenon is crucial for the parasite growth and virulence, elucidation of precise steps in the export pathway is still required. A translocon protein complex, PTEX, is the only known pathway that mediates passage of exported proteins across the PVM. P. falciparum Parasitophorous Vacuolar protein 1 (PfPV1), a previously reported parasitophorous vacuole (PV) protein, is considered essential for parasite growth. In this study, we characterized PfPV1 as a novel merozoite dense granule protein. Structured illumination microscopy (SIM) analyses demonstrated that PfPV1 partially co-localized with EXP2, suggesting the protein could be a PTEX accessory molecule. Furthermore, PfPV1 and exported protein PTP5 co-immunoprecipitated with anti-PfPV1 antibody. Surface plasmon resonance (SPR) confirmed the proteins’ direct interaction. Additionally, we identified a PfPV1 High-affinity Region (PHR) at the C-terminal side of PTP5 where PfPV1 dominantly bound. SIM analysis demonstrated an export arrest of PTP5ΔPHR, a PTP5 mutant lacking PHR, suggesting PHR is essential for PTP5 export to the infected erythrocyte cytosol. The overall results suggest that PfPV1, a novel dense granule protein, plays an important role in protein export at PV.
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Affiliation(s)
- Masayuki Morita
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Edward H Ntege
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Bernard N Kanoi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Daisuke Ito
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan.,Division of Medical Zoology, Department of Microbiology and Immunology, Faculty of Medicine, Tottori University, Yonago, Tottori, 683-8503, Japan
| | - Takahiro Nakata
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Ji-Won Lee
- Division of Bio-Imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime, Japan
| | | | - Tadahiro Iimura
- Division of Bio-Imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime, Japan.,Division of Analytical Bio-Medicine, Advanced Research Support Center, Ehime University, Shitsukawa, Toon, Ehime, Japan
| | - Motomi Torii
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime, Japan
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan.
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45
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Sherling ES, van Ooij C. Host cell remodeling by pathogens: the exomembrane system in Plasmodium-infected erythrocytes. FEMS Microbiol Rev 2017; 40:701-21. [PMID: 27587718 PMCID: PMC5007283 DOI: 10.1093/femsre/fuw016] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2016] [Indexed: 12/22/2022] Open
Abstract
Malaria is caused by infection of erythrocytes by parasites of the genus Plasmodium. To survive inside erythrocytes, these parasites induce sweeping changes within the host cell, one of the most dramatic of which is the formation of multiple membranous compartments, collectively referred to as the exomembrane system. As an uninfected mammalian erythrocyte is devoid of internal membranes, the parasite must be the force and the source behind the formation of these compartments. Even though the first evidence of the presence these of internal compartments was obtained over a century ago, their functions remain mostly unclear, and in some cases completely unknown, and the mechanisms underlying their formation are still mysterious. In this review, we provide an overview of the different parts of the exomembrane system, describing the parasitophorous vacuole, the tubovesicular network, Maurer's clefts, the caveola-vesicle complex, J dots and other mobile compartments, and the small vesicles that have been observed in Plasmodium-infected cells. Finally, we combine the data into a simplified view of the exomembrane system and its relation to the alterations of the host erythrocyte. Plasmodium parasites remodel the host erythrocyte in various ways, including the formation of several membranous compartments, together referred to as the exomembrane system, within the erythrocyte cytosol that together are key to the sweeping changes in the host cell.
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Affiliation(s)
- Emma S Sherling
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Christiaan van Ooij
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK
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46
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Abdi A, Yu L, Goulding D, Rono MK, Bejon P, Choudhary J, Rayner J. Proteomic analysis of extracellular vesicles from a Plasmodium falciparum Kenyan clinical isolate defines a core parasite secretome. Wellcome Open Res 2017; 2:50. [PMID: 28944300 PMCID: PMC5583745 DOI: 10.12688/wellcomeopenres.11910.2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Many pathogens secrete effector molecules to subvert host immune responses, to acquire nutrients, and/or to prepare host cells for invasion. One of the ways that effector molecules are secreted is through extracellular vesicles (EVs) such as exosomes. Recently, the malaria parasite P. falciparum has been shown to produce EVs that can mediate transfer of genetic material between parasites and induce sexual commitment. Characterizing the content of these vesicles may improve our understanding of P. falciparum pathogenesis and virulence. METHODS Previous studies of P. falciparum EVs have been limited to long-term adapted laboratory isolates. In this study, we isolated EVs from a Kenyan P. falciparum clinical isolate adapted to in vitro culture for a short period and characterized their protein content by mass spectrometry (data are available via ProteomeXchange, with identifier PXD006925). RESULTS We show that P. falciparum extracellular vesicles ( PfEVs) are enriched in proteins found within the exomembrane compartments of infected erythrocytes such as Maurer's clefts (MCs), as well as the secretory endomembrane compartments in the apical end of the merozoites, suggesting that these proteins play a role in parasite-host interactions. Comparison of this novel clinically relevant dataset with previously published datasets helps to define a core secretome present in Plasmodium EVs. CONCLUSIONS P. falciparum extracellular vesicles contain virulence-associated parasite proteins. Therefore, analysis of PfEVs contents from a range of clinical isolates, and their functional validation may improve our understanding of the virulence mechanisms of the parasite, and potentially identify targets for interventions or diagnostics.
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Affiliation(s)
- Abdirahman Abdi
- Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya.,KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Lu Yu
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - David Goulding
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Martin K Rono
- Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya.,KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Jyoti Choudhary
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Julian Rayner
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
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47
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Abdi A, Yu L, Goulding D, Rono MK, Bejon P, Choudhary J, Rayner J. Proteomic analysis of extracellular vesicles from a Plasmodium falciparum Kenyan clinical isolate defines a core parasite secretome. Wellcome Open Res 2017. [PMID: 28944300 DOI: 10.12688/wellcomeopenres.11910.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Many pathogens secrete effector molecules to subvert host immune responses, to acquire nutrients, and/or to prepare host cells for invasion. One of the ways that effector molecules are secreted is through extracellular vesicles (EVs) such as exosomes. Recently, the malaria parasite P. falciparum has been shown to produce EVs that can mediate transfer of genetic material between parasites and induce sexual commitment. Characterizing the content of these vesicles may improve our understanding of P. falciparum pathogenesis and virulence. METHODS Previous studies of P. falciparum EVs have been limited to long-term adapted laboratory isolates. In this study, we isolated EVs from a Kenyan P. falciparum clinical isolate adapted to in vitro culture for a short period and characterized their protein content by mass spectrometry (data are available via ProteomeXchange, with identifier PXD006925). RESULTS We show that P. falciparum extracellular vesicles ( PfEVs) are enriched in proteins found within the exomembrane compartments of infected erythrocytes such as Maurer's clefts (MCs), as well as the secretory endomembrane compartments in the apical end of the merozoites, suggesting that these proteins play a role in parasite-host interactions. Comparison of this novel clinically relevant dataset with previously published datasets helps to define a core secretome present in Plasmodium EVs. CONCLUSIONS P. falciparum extracellular vesicles contain virulence-associated parasite proteins. Therefore, analysis of PfEVs contents from a range of clinical isolates, and their functional validation may improve our understanding of the virulence mechanisms of the parasite, and potentially identify targets for interventions or diagnostics.
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Affiliation(s)
- Abdirahman Abdi
- Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya.,KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Lu Yu
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - David Goulding
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Martin K Rono
- Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya.,KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Jyoti Choudhary
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Julian Rayner
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
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The Exported Chaperone PfHsp70x Is Dispensable for the Plasmodium falciparum Intraerythrocytic Life Cycle. mSphere 2017; 2:mSphere00363-17. [PMID: 28959740 PMCID: PMC5615134 DOI: 10.1128/msphere.00363-17] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 09/07/2017] [Indexed: 11/24/2022] Open
Abstract
Half of the world’s population lives at risk for malaria. The intraerythrocytic life cycle of Plasmodium spp. is responsible for clinical manifestations of malaria; therefore, knowledge of the parasite’s ability to survive within the erythrocyte is needed to combat the deadliest agent of malaria, P. falciparum. An outstanding question in the field is how P. falciparum undertakes the essential process of trafficking its proteins within the host cell. In most organisms, chaperones such as Hsp70 are employed in protein trafficking. Of the Plasmodium species causing human disease, the chaperone PfHsp70x is unique to P. falciparum, and it is the only parasite protein of its kind exported to the host (S. Külzer et al., Cell Microbiol 14:1784–1795, 2012). This has placed PfHsp70x as an ideal target to inhibit protein trafficking and kill the parasite. However, we show that PfHsp70x is not required for export of parasite effectors and it is not essential for parasite survival inside the RBC. Export of parasite proteins into the host erythrocyte is essential for survival of Plasmodium falciparum during its asexual life cycle. While several studies described key factors within the parasite that are involved in protein export, the mechanisms employed to traffic exported proteins within the host cell are currently unknown. Members of the Hsp70 family of chaperones, together with their Hsp40 cochaperones, facilitate protein trafficking in other organisms, and are thus likely used by P. falciparum in the trafficking of its exported proteins. A large group of Hsp40 proteins is encoded by the parasite and exported to the host cell, but only one Hsp70, P. falciparum Hsp70x (PfHsp70x), is exported with them. PfHsp70x is absent in most Plasmodium species and is found only in P. falciparum and closely related species that infect apes. Herein, we have utilized clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 genome editing in P. falciparum to investigate the essentiality of PfHsp70x. We show that parasitic growth was unaffected by knockdown of PfHsp70x using both the dihydrofolate reductase (DHFR)-based destabilization domain and the glmS ribozyme system. Similarly, a complete gene knockout of PfHsp70x did not affect the ability of P. falciparum to proceed through its intraerythrocytic life cycle. The effect of PfHsp70x knockdown/knockout on the export of proteins to the host red blood cell (RBC), including the critical virulence factor P. falciparum erythrocyte membrane protein 1 (PfEMP1), was tested, and we found that this process was unaffected. These data show that although PfHsp70x is the sole exported Hsp70, it is not essential for the asexual development of P. falciparum. IMPORTANCE Half of the world’s population lives at risk for malaria. The intraerythrocytic life cycle of Plasmodium spp. is responsible for clinical manifestations of malaria; therefore, knowledge of the parasite’s ability to survive within the erythrocyte is needed to combat the deadliest agent of malaria, P. falciparum. An outstanding question in the field is how P. falciparum undertakes the essential process of trafficking its proteins within the host cell. In most organisms, chaperones such as Hsp70 are employed in protein trafficking. Of the Plasmodium species causing human disease, the chaperone PfHsp70x is unique to P. falciparum, and it is the only parasite protein of its kind exported to the host (S. Külzer et al., Cell Microbiol 14:1784–1795, 2012). This has placed PfHsp70x as an ideal target to inhibit protein trafficking and kill the parasite. However, we show that PfHsp70x is not required for export of parasite effectors and it is not essential for parasite survival inside the RBC.
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Nyboer B, Heiss K, Mueller AK, Ingmundson A. The Plasmodium liver-stage parasitophorous vacuole: A front-line of communication between parasite and host. Int J Med Microbiol 2017; 308:107-117. [PMID: 28964681 DOI: 10.1016/j.ijmm.2017.09.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/19/2017] [Accepted: 09/11/2017] [Indexed: 12/13/2022] Open
Abstract
The intracellular development and differentiation of the Plasmodium parasite in the host liver is a prerequisite for the actual onset of malaria disease pathology. Since liver-stage infection is clinically silent and can be completely eliminated by sterilizing immune responses, it is a promising target for urgently needed innovative antimalarial drugs and/or vaccines. Discovered more than 65 years ago, these stages remain poorly understood regarding their molecular repertoire and interaction with their host cells in comparison to the pathogenic erythrocytic stages. The differentiating and replicative intrahepatic parasite resides in a membranous compartment called the parasitophorous vacuole, separating it from the host-cell cytoplasm. Here we outline seminal work that contributed to our present understanding of the fundamental dynamic cellular processes of the intrahepatic malarial parasite with both specific host-cell factors and compartments.
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Affiliation(s)
- Britta Nyboer
- Centre for Infectious Diseases, Parasitology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Kirsten Heiss
- Centre for Infectious Diseases, Parasitology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; Centre for Infection Research (DZIF), D 69120 Heidelberg, Germany
| | - Ann-Kristin Mueller
- Centre for Infectious Diseases, Parasitology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; Centre for Infection Research (DZIF), D 69120 Heidelberg, Germany,.
| | - Alyssa Ingmundson
- Department of Molecular Parasitology, Institute of Biology, Humboldt University Berlin, Philippstrasse 13, 10115 Berlin, Germany.
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Khosh-Naucke M, Becker J, Mesén-Ramírez P, Kiani P, Birnbaum J, Fröhlke U, Jonscher E, Schlüter H, Spielmann T. Identification of novel parasitophorous vacuole proteins in P. falciparum parasites using BioID. Int J Med Microbiol 2017; 308:13-24. [PMID: 28784333 DOI: 10.1016/j.ijmm.2017.07.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022] Open
Abstract
Malaria blood stage parasites develop within red blood cells where they are contained in a vacuolar compartment known as the parasitophorous vacuole (PV). This compartment holds a key role in the interaction of the parasite with its host cell. However, the proteome of this compartment has so far not been comprehensively analysed. Here we used BioID in asexual blood stages of the most virulent human malaria parasite Plasmodium falciparum to identify new proteins of the PV. The resulting proteome contained many of the already known PV proteins and validation by GFP-knock-in of 10 previously in P. falciparum uncharacterised hits revealed 5 new PV proteins and two with a partial PV localisation. This included proteins peripherally attached to the inner face of the PV membrane as well as proteins anchored in the parasite plasma membrane that protrude into the PV. Using selectable targeted gene disruption we generated mutants for 2 of the 10 candidates. In contrast we could not select parasites with disruptions for another 3 candidates, strongly suggesting that they are important for parasite growth. Interestingly, one of these included the orthologue of UIS2, a protein previously proposed to regulate protein translation in the parasite cytoplasm but here shown to be an essential PV protein. This work extends the number of known PV proteins and provides a starting point for further functional analyses of this compartment.
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Affiliation(s)
- Melissa Khosh-Naucke
- Bernhard Nocht Institute for Tropical Medicine, Parasitology Section, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany
| | - Johanna Becker
- Bernhard Nocht Institute for Tropical Medicine, Parasitology Section, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany
| | - Paolo Mesén-Ramírez
- Bernhard Nocht Institute for Tropical Medicine, Parasitology Section, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany
| | - Parnian Kiani
- Core Facility Mass Spectrometric Proteomics, Institute of Clinical Chemistry, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Jakob Birnbaum
- Bernhard Nocht Institute for Tropical Medicine, Parasitology Section, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany
| | - Ulrike Fröhlke
- Bernhard Nocht Institute for Tropical Medicine, Parasitology Section, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany
| | - Ernst Jonscher
- Bernhard Nocht Institute for Tropical Medicine, Parasitology Section, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany
| | - Hartmut Schlüter
- Core Facility Mass Spectrometric Proteomics, Institute of Clinical Chemistry, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Tobias Spielmann
- Bernhard Nocht Institute for Tropical Medicine, Parasitology Section, Bernhard-Nocht-Straße 74, 20359 Hamburg, Germany.
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