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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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2
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Levray YS, Bana B, Tarr SJ, McLaughlin EJ, Rossi-Smith P, Waltho A, Charlton GH, Chiozzi RZ, Straton CR, Thalassinos K, Osborne AR. Formation of ER-lumenal intermediates during export of Plasmodium proteins containing transmembrane-like hydrophobic sequences. PLoS Pathog 2023; 19:e1011281. [PMID: 37000891 PMCID: PMC10096305 DOI: 10.1371/journal.ppat.1011281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 04/12/2023] [Accepted: 03/08/2023] [Indexed: 04/03/2023] Open
Abstract
During the blood stage of a malaria infection, malaria parasites export both soluble and membrane proteins into the erythrocytes in which they reside. Exported proteins are trafficked via the parasite endoplasmic reticulum and secretory pathway, before being exported across the parasitophorous vacuole membrane into the erythrocyte. Transport across the parasitophorous vacuole membrane requires protein unfolding, and in the case of membrane proteins, extraction from the parasite plasma membrane. We show that trafficking of the exported Plasmodium protein, Pf332, differs from that of canonical eukaryotic soluble-secreted and transmembrane proteins. Pf332 is initially ER-targeted by an internal hydrophobic sequence that unlike a signal peptide, is not proteolytically removed, and unlike a transmembrane segment, does not span the ER membrane. Rather, both termini of the hydrophobic sequence enter the ER-lumen and the ER-lumenal species is a productive intermediate for protein export. Furthermore, we show in intact cells, that two other exported membrane proteins, SBP1 and MAHRP2, assume a lumenal topology within the parasite secretory pathway. Although the addition of a C-terminal ER-retention sequence, recognised by the lumenal domain of the KDEL receptor, does not completely block export of SBP1 and MAHRP2, it does enhance their retention in the parasite ER. This indicates that a sub-population of each protein adopts an ER-lumenal state that is an intermediate in the export process. Overall, this suggests that although many exported proteins traverse the parasite secretory pathway as typical soluble or membrane proteins, some exported proteins that are ER-targeted by a transmembrane segment-like, internal, non-cleaved hydrophobic segment, do not integrate into the ER membrane, and form an ER-lumenal species that is a productive export intermediate. This represents a novel means, not seen in typical membrane proteins found in model systems, by which exported transmembrane-like proteins can be targeted and trafficked within the lumen of the secretory pathway.
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3
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Polino AJ, Hasan MM, Floyd K, Avila-Cruz Y, Yang Y, Goldberg DE. An essential endoplasmic reticulum-resident N-acetyltransferase ortholog in Plasmodium falciparum. J Cell Sci 2023; 136:286919. [PMID: 36744402 PMCID: PMC10038149 DOI: 10.1242/jcs.260551] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 01/27/2023] [Indexed: 02/07/2023] Open
Abstract
N-terminal acetylation is a common eukaryotic protein modification that involves the addition of an acetyl group to the N-terminus of a polypeptide. This modification is largely performed by cytosolic N-terminal acetyltransferases (NATs). Most associate with the ribosome, acetylating nascent polypeptides co-translationally. In the malaria parasite Plasmodium falciparum, exported effectors are thought to be translated into the endoplasmic reticulum (ER), processed by the aspartic protease plasmepsin V and then N-acetylated, despite having no clear access to cytosolic NATs. Here, we used inducible gene deletion and post-transcriptional knockdown to investigate the primary ER-resident NAT candidate, Pf3D7_1437000. We found that it localizes to the ER and is required for parasite growth. However, depletion of Pf3D7_1437000 had no effect on protein export or acetylation of the exported proteins HRP2 and HRP3. Despite this, Pf3D7_1437000 depletion impedes parasite development within the host red blood cell and prevents parasites from completing genome replication. Thus, this work provides further proof of N-terminal acetylation of secretory system proteins, a process unique to apicomplexan parasites, but strongly discounts a promising candidate for this post-translational modification.
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Affiliation(s)
- Alexander J Polino
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Muhammad M Hasan
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Katherine Floyd
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Yolotzin Avila-Cruz
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Yujuan Yang
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
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4
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Nyonda MA, Boyer JB, Belmudes L, Krishnan A, Pino P, Couté Y, Brochet M, Meinnel T, Soldati-Favre D, Giglione C. N-Acetylation of secreted proteins is widespread in Apicomplexa and independent of acetyl-CoA ER-transporter AT1. J Cell Sci 2022; 135:275539. [PMID: 35621049 DOI: 10.1242/jcs.259811] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 05/05/2022] [Indexed: 11/20/2022] Open
Abstract
Acetyl-CoA participates in post-translational modification of proteins, central carbon and lipid metabolism in several cell compartments. In mammals, the acetyl-CoA transporter 1 (AT1) facilitates the flux of cytosolic acetyl-CoA into the endoplasmic reticulum (ER), enabling the acetylation of proteins of the secretory pathway, in concert with dedicated acetyltransferases including NAT8. However, the implication of the ER acetyl-CoA pool in acetylation of ER-transiting proteins in Apicomplexa is unknown. We identify homologues of AT1 and NAT8 in Toxoplasma gondii and Plasmodium berghei. Proteome-wide analyses revealed widespread N-terminal acetylation marks of secreted proteins in both parasites. Such acetylation profile of N-terminally processed proteins was never observed so far in any other organisms. AT1 deletion resulted in a considerable reduction of parasite fitness. In P. berghei, AT1 is important for growth of asexual blood stages and production of female gametocytes and male gametocytogenesis impaling its requirement for transmission. In the absence of AT1, the lysine and N-terminal acetylation sites remained globally unaltered, suggesting an uncoupling between the role of AT1 in development and active acetylation occurring along the secretory pathway.
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Affiliation(s)
- Mary Akinyi Nyonda
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Jean-Baptiste Boyer
- Université Paris-Saclay, CEA, CNRS, Institute for Intergrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Lucid Belmudes
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Aarti Krishnan
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Paco Pino
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland.,ExcellGene SA, CH1870 Monthey, Switzerland
| | - Yohann Couté
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Mathieu Brochet
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Thierry Meinnel
- Université Paris-Saclay, CEA, CNRS, Institute for Intergrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Carmela Giglione
- Université Paris-Saclay, CEA, CNRS, Institute for Intergrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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5
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Kumar T, Maitra S, Rahman A, Bhattacharjee S. A conserved guided entry of tail-anchored pathway is involved in the trafficking of a subset of membrane proteins in Plasmodium falciparum. PLoS Pathog 2021; 17:e1009595. [PMID: 34780541 PMCID: PMC8629386 DOI: 10.1371/journal.ppat.1009595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 11/29/2021] [Accepted: 10/19/2021] [Indexed: 01/22/2023] Open
Abstract
Tail-anchored (TA) proteins are defined by the absence of N-terminus signal sequence and the presence of a single transmembrane domain (TMD) proximal to their C-terminus. They play fundamental roles in cellular processes including vesicular trafficking, protein translocation and quality control. Some of the TA proteins are post-translationally integrated by the Guided Entry of TA (GET) pathway to the cellular membranes; with their N-terminus oriented towards the cytosol and C-terminus facing the organellar lumen. The TA repertoire and the GET machinery have been extensively characterized in the yeast and mammalian systems, however, they remain elusive in the human malaria parasite Plasmodium falciparum. In this study, we bioinformatically predicted a total of 63 TA proteins in the P. falciparum proteome and revealed the association of a subset with the P. falciparum homolog of Get3 (PfGet3). In addition, our proximity labelling studies either definitively identified or shortlisted the other eligible GET constituents, and our in vitro association studies validated associations between PfGet3 and the corresponding homologs of Get4 and Get2 in P. falciparum. Collectively, this study reveals the presence of proteins with hallmark TA signatures and the involvement of evolutionary conserved GET trafficking pathway for their targeted delivery within the parasite. Tail-anchored (TA) membrane proteins are known to play essential cellular functions in the eukaryotes. These proteins are trafficked to their respective destinations by post-translational translocation pathways that are evolutionarily conserved from yeast to human. However, they remain unidentified in the malaria parasite Plasmodium falciparum. We have used bioinformatic prediction algorithms in conjunction with functional validation studies to identify the candidate TA repertoire and some of the homologs of the trafficking machinery in P. falciparum. Initially, we predicted the presence of 63 putative TA proteins localized to distinct compartments within this parasite, including a few confirmed TA homologs in other eukaryotic systems. We then identified and characterized PfGet3 as a central component in the Guided-Entry of TA (GET) translocation machinery, and our bacterial co-expression and pulldown assays with two selected recombinant TA proteins, PfBOS1 and PfUSE1, showed co-association with PfGet3. We also identified PfGet2 and PfGet4 as the other two components of the GET machinery in P. falciparum using proximity biotinylation followed by mass spectrometry. Interestingly, we also found six TA proteins in the parasite enriched in this fraction. We further validated the direct interactions between a few TA candidates, PfGet4 and PfGet2 with PfGet3 using recombinant-based pulldown studies. In conclusion, this study classified a subset of membrane proteins with the TA nomenclature and implicated a previously unidentified GET pathway for their translocation in this apicomplexan parasite.
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Affiliation(s)
- Tarkeshwar Kumar
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Satarupa Maitra
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Abdur Rahman
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Souvik Bhattacharjee
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
- * E-mail:
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6
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Das S, Roy B, Chakrabarty S. Non-ribosomal insights into ribosomal P2 protein in Plasmodium falciparum-infected erythrocytes. Microbiologyopen 2021; 10:e1188. [PMID: 34459544 PMCID: PMC8380560 DOI: 10.1002/mbo3.1188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 04/10/2021] [Indexed: 11/12/2022] Open
Abstract
The enormous complexity of the eukaryotic ribosome has been a real challenge in unlocking the mechanistic aspects of its amazing molecular function during mRNA translation and many non‐canonical activities of ribosomal proteins in eukaryotic cells. While exploring the uncanny nature of ribosomal P proteins in malaria parasites Plasmodium falciparum, the 60S stalk ribosomal P2 protein has been shown to get exported to the infected erythrocyte (IE) surface as an SDS‐resistant oligomer during the early to the mid‐trophozoite stage. Inhibiting IE surface P2 either by monoclonal antibody or through genetic knockdown resulted in nuclear division arrest of the parasite. This strange and serendipitous finding has led us to explore more about un‐canonical cell biology and the structural involvement of P2 protein in Plasmodium in the search for a novel biochemical role during parasite propagation in the human host.
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Affiliation(s)
- Sudipta Das
- Asymmetric Cell Division Laboratory, Division of Infectious Disease and Immunology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Bhaskar Roy
- Asymmetric Cell Division Laboratory, Division of Infectious Disease and Immunology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Saswata Chakrabarty
- Asymmetric Cell Division Laboratory, Division of Infectious Disease and Immunology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
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7
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Nasamu AS, Polino AJ, Istvan ES, Goldberg DE. Malaria parasite plasmepsins: More than just plain old degradative pepsins. J Biol Chem 2020; 295:8425-8441. [PMID: 32366462 PMCID: PMC7307202 DOI: 10.1074/jbc.rev120.009309] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Plasmepsins are a group of diverse aspartic proteases in the malaria parasite Plasmodium Their functions are strikingly multifaceted, ranging from hemoglobin degradation to secretory organelle protein processing for egress, invasion, and effector export. Some, particularly the digestive vacuole plasmepsins, have been extensively characterized, whereas others, such as the transmission-stage plasmepsins, are minimally understood. Some (e.g. plasmepsin V) have exquisite cleavage sequence specificity; others are fairly promiscuous. Some have canonical pepsin-like aspartic protease features, whereas others have unusual attributes, including the nepenthesin loop of plasmepsin V and a histidine in place of a catalytic aspartate in plasmepsin III. We have learned much about the functioning of these enzymes, but more remains to be discovered about their cellular roles and even their mechanisms of action. Their importance in many key aspects of parasite biology makes them intriguing targets for antimalarial chemotherapy. Further consideration of their characteristics suggests that some are more viable drug targets than others. Indeed, inhibitors of invasion and egress offer hope for a desperately needed new drug to combat this nefarious organism.
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Affiliation(s)
- Armiyaw S Nasamu
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alexander J Polino
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Eva S Istvan
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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8
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Kanyal A, Rawat M, Gurung P, Choubey D, Anamika K, Karmodiya K. Genome‐wide survey and phylogenetic analysis of histone acetyltransferases and histone deacetylases of
Plasmodium falciparum. FEBS J 2018; 285:1767-1782. [DOI: 10.1111/febs.14376] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/20/2017] [Accepted: 12/22/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Abhishek Kanyal
- Department of Biology Indian Institute of Science Education and Research Pashan, Pune India
| | - Mukul Rawat
- Department of Biology Indian Institute of Science Education and Research Pashan, Pune India
| | - Pratima Gurung
- Department of Biology Indian Institute of Science Education and Research Pashan, Pune India
| | | | | | - Krishanpal Karmodiya
- Department of Biology Indian Institute of Science Education and Research Pashan, Pune India
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9
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Abstract
The intracellular protozoan Toxoplasma gondii dramatically reprograms the transcriptome of host cells it infects, including substantially up-regulating the host oncogene c-myc. By applying a flow cytometry-based selection to infected mouse cells expressing green fluorescent protein fused to c-Myc (c-Myc–GFP), we isolated mutant tachyzoites defective in this host c-Myc up-regulation. Whole-genome sequencing of three such mutants led to the identification of MYR1 (Myc regulation 1; TGGT1_254470) as essential for c-Myc induction. MYR1 is a secreted protein that requires TgASP5 to be cleaved into two stable portions, both of which are ultimately found within the parasitophorous vacuole and at the parasitophorous vacuole membrane. Deletion of MYR1 revealed that in addition to its requirement for c-Myc up-regulation, the MYR1 protein is needed for the ability of Toxoplasma tachyzoites to modulate several other important host pathways, including those mediated by the dense granule effectors GRA16 and GRA24. This result, combined with its location at the parasitophorous vacuole membrane, suggested that MYR1 might be a component of the machinery that translocates Toxoplasma effectors from the parasitophorous vacuole into the host cytosol. Support for this possibility was obtained by showing that transit of GRA24 to the host nucleus is indeed MYR1-dependent. As predicted by this pleiotropic phenotype, parasites deficient in MYR1 were found to be severely attenuated in a mouse model of infection. We conclude, therefore, that MYR1 is a novel protein that plays a critical role in how Toxoplasma delivers effector proteins to the infected host cell and that this is crucial to virulence. Toxoplasma gondii is an important human pathogen and a model for the study of intracellular parasitism. Infection of the host cell with Toxoplasma tachyzoites involves the introduction of protein effectors, including many that are initially secreted into the parasitophorous vacuole but must ultimately translocate to the host cell cytosol to function. The work reported here identified a novel protein that is required for this translocation. These results give new insight into a very unusual cell biology process as well as providing a potential handle on a pathway that is necessary for virulence and, therefore, a new potential target for chemotherapy.
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10
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Sappakhaw K, Takasila R, Sittikul P, Wattana-Amorn P, Assavalapsakul W, Boonyalai N. Biochemical characterization of plasmepsin V from Plasmodium vivax Thailand isolates: Substrate specificity and enzyme inhibition. Mol Biochem Parasitol 2016; 204:51-63. [PMID: 26795263 DOI: 10.1016/j.molbiopara.2016.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 01/05/2016] [Accepted: 01/08/2016] [Indexed: 12/19/2022]
Abstract
Plasmepsin V (PMV) is a Plasmodium aspartic protease responsible for the cleavage of the Plasmodium export element (PEXEL) motif, which is an essential step for export of PEXEL containing proteins and crucial for parasite viability. Here we describe the genetic polymorphism of Plasmodium vivax PMV (PvPMV) Thailand isolates, followed by cloning, expression, purification and characterization of PvPMV-Thai, presenting the pro- and mature-form of PvPMV-Thai. With our refolding and purification method, approximately 1mg of PvPMV-Thai was obtained from 1g of washed inclusion bodies. Unlike PvPMV-Ind and PvPMV-Sal-1, PvPMV-Thai contains a four-amino acid insertion (SVSE) at residues 246-249. We have confirmed that this insertion did not interfere with the catalytic activity as it is located in the long loop (R241-E272) pointing away from the substrate-binding pocket. PvPMV-Thai exhibited similar activity to PfPMV counterparts in which PfEMP2 could be hydrolyzed more efficiently than HRPII. Substrate specificity studies at P1' showed that replacing Ser by Val or Glu of the PfEMP2 peptide markedly reduced the enzyme activity of PvPMV similar to that of PfPMV whereas replacing His by Val or Ser of the HRPII peptide increased the cleavage activity. However, the substitution of amino acids at the P2 position with Glu dramatically reduced the cleavage efficiency by 80% in PvPMV in contrast to 30% in PfPMV, indicating subtle differences around the S2 binding pocket of both PfPMV and PvPMV. Four inhibitors were also evaluated for PvPMV-Thai activity including PMSF, pepstatin A, nelfinavir, and menisporopsin A-a macrocyclic polylactone. We are the first to show that menisporopsin A partially inhibits the PvPMV-Thai activity at high concentration. Taken together, these findings provide insights into recombinant production, substrate specificity and inhibition of PvPMV-Thai.
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Affiliation(s)
- Khomkrit Sappakhaw
- Department of Biochemistry, Special Research Unit for Protein Engineering and Protein Bioinformatics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand
| | - Ratchaneekorn Takasila
- Department of Biochemistry, Special Research Unit for Protein Engineering and Protein Bioinformatics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand
| | - Pichamon Sittikul
- Department of Biochemistry, Special Research Unit for Protein Engineering and Protein Bioinformatics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand
| | - Pakorn Wattana-Amorn
- Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand; Department of Chemistry, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand
| | - Wanchai Assavalapsakul
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Nonlawat Boonyalai
- Department of Biochemistry, Special Research Unit for Protein Engineering and Protein Bioinformatics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand; Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand.
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11
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Spielmann T, Gilberger TW. Critical Steps in Protein Export of Plasmodium falciparum Blood Stages. Trends Parasitol 2015; 31:514-525. [DOI: 10.1016/j.pt.2015.06.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/16/2015] [Accepted: 06/24/2015] [Indexed: 11/29/2022]
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12
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Mbengue A, Bhattacharjee S, Pandharkar T, Liu H, Estiu G, Stahelin RV, Rizk SS, Njimoh DL, Ryan Y, Chotivanich K, Nguon C, Ghorbal M, Lopez-Rubio JJ, Pfrender M, Emrich S, Mohandas N, Dondorp AM, Wiest O, Haldar K. A molecular mechanism of artemisinin resistance in Plasmodium falciparum malaria. Nature 2015; 520:683-7. [PMID: 25874676 PMCID: PMC4417027 DOI: 10.1038/nature14412] [Citation(s) in RCA: 396] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 03/19/2015] [Indexed: 11/08/2022]
Abstract
Artemisinins are the cornerstone of anti-malarial drugs. Emergence and spread of resistance to them raises risk of wiping out recent gains achieved in reducing worldwide malaria burden and threatens future malaria control and elimination on a global level. Genome-wide association studies (GWAS) have revealed parasite genetic loci associated with artemisinin resistance. However, there is no consensus on biochemical targets of artemisinin. Whether and how these targets interact with genes identified by GWAS, remains unknown. Here we provide biochemical and cellular evidence that artemisinins are potent inhibitors of Plasmodium falciparum phosphatidylinositol-3-kinase (PfPI3K), revealing an unexpected mechanism of action. In resistant clinical strains, increased PfPI3K was associated with the C580Y mutation in P. falciparum Kelch13 (PfKelch13), a primary marker of artemisinin resistance. Polyubiquitination of PfPI3K and its binding to PfKelch13 were reduced by the PfKelch13 mutation, which limited proteolysis of PfPI3K and thus increased levels of the kinase, as well as its lipid product phosphatidylinositol-3-phosphate (PI3P). We find PI3P levels to be predictive of artemisinin resistance in both clinical and engineered laboratory parasites as well as across non-isogenic strains. Elevated PI3P induced artemisinin resistance in absence of PfKelch13 mutations, but remained responsive to regulation by PfKelch13. Evidence is presented for PI3P-dependent signalling in which transgenic expression of an additional kinase confers resistance. Together these data present PI3P as the key mediator of artemisinin resistance and the sole PfPI3K as an important target for malaria elimination.
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Affiliation(s)
- Alassane Mbengue
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Souvik Bhattacharjee
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Trupti Pandharkar
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Haining Liu
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Guillermina Estiu
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Robert V Stahelin
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA [3] Department of Biochemistry &Molecular Biology, Indiana University School of Medicine-South Bend, 143 Raclin-Carmichael Hall, 1234 Notre Dame Avenue, South Bend, Indiana 46617, USA
| | - Shahir S Rizk
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Dieudonne L Njimoh
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA [3] Departmen of. Biochemistry and Molecular Biology, Faculty of Science University of Buea, P.O. Box 63 Buea, Southwest region, Cameroon
| | - Yana Ryan
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Kesinee Chotivanich
- Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand
| | - Chea Nguon
- National Center for Parasitology, Entomology and Malaria Control, 12302 Phnom Penh, Monivong Blvd, Phnom Penh 12302, Cambodia
| | - Mehdi Ghorbal
- CNRS 5290/IRD 224/University Montpellier 1&2 ("MiVEGEC"), Montpellier, France
| | | | - Michael Pfrender
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Scott Emrich
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana 46556. USA
| | | | - Arjen M Dondorp
- 1] Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand [2] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7BN. UK
| | - Olaf Wiest
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA [3] Laboratory of Computational Chemistry and Drug Design, Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Kasturi Haldar
- 1] Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
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Tarr SJ, Osborne AR. Experimental determination of the membrane topology of the Plasmodium protease Plasmepsin V. PLoS One 2015; 10:e0121786. [PMID: 25849462 PMCID: PMC4388684 DOI: 10.1371/journal.pone.0121786] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 02/07/2015] [Indexed: 11/23/2022] Open
Abstract
The malaria parasite exports hundreds of proteins into its host cell. The majority of exported proteins contain a Host-Targeting motif (also known as a Plasmodium export element) that directs them for export. Prior to export, the Host-Targeting motif is cleaved by the endoplasmic reticulum-resident protease Plasmepsin V and the newly generated N-terminus is N-α-acetylated by an unidentified enzyme. The cleaved, N-α-acetylated protein is trafficked to the parasitophorous vacuole, where it is translocated across the vacuole membrane. It is clear that cleavage and N-α-acetylation of the Host-Targeting motif occur at the endoplasmic reticulum, and it has been proposed that Host-Targeting motif cleavage and N-α-acetylation occur either on the luminal or cytosolic side of the endoplasmic reticulum membrane. Here, we use self-associating ‘split’ fragments of GFP to determine the topology of Plasmepsin V in the endoplasmic reticulum membrane; we show that the catalytic protease domain of Plasmepsin V faces the endoplasmic reticulum lumen. These data support a model in which the Host-Targeting motif is cleaved and N-α-acetylated in the endoplasmic reticulum lumen. Furthermore, these findings suggest that cytosolic N-α-acetyltransferases are unlikely to be candidates for the N-α-acetyltransferase of Host-Targeting motif-containing exported proteins.
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Affiliation(s)
- Sarah J. Tarr
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, United Kingdom
| | - Andrew R. Osborne
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, United Kingdom
- * E-mail:
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14
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Mbengue A, Vialla E, Berry L, Fall G, Audiger N, Demettre-Verceil E, Boteller D, Braun-Breton C. New Export Pathway inPlasmodium falciparum-Infected Erythrocytes: Role of the Parasite Group II Chaperonin, PfTRiC. Traffic 2015; 16:461-75. [DOI: 10.1111/tra.12266] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Alassane Mbengue
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Emilie Vialla
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Laurence Berry
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Gamou Fall
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Nicolas Audiger
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Edith Demettre-Verceil
- Plate-forme de Protéomique Fonctionnelle - FPP; UMS CNRS 3426 - US 009 INSERM - UMI - UMII, IGF; 141 rue de la Cardonille 34094 Montpellier Cedex 5 France
| | - David Boteller
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
| | - Catherine Braun-Breton
- University Montpellier II; CNRS UMR 5235, University Montpellier I; Dynamique des Interactions Membranaires Normales et Pathologiques 34095 Montpellier Cedex 5 France
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15
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Spillman NJ, Beck JR, Goldberg DE. Protein export into malaria parasite-infected erythrocytes: mechanisms and functional consequences. Annu Rev Biochem 2015; 84:813-41. [PMID: 25621510 DOI: 10.1146/annurev-biochem-060614-034157] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phylum Apicomplexa comprises a large group of obligate intracellular parasites of high medical and veterinary importance. These organisms succeed intracellularly by effecting remarkable changes in a broad range of diverse host cells. The transformation of the host erythrocyte is particularly striking in the case of the malaria parasite Plasmodium falciparum. P. falciparum exports hundreds of proteins that mediate a complex cellular renovation marked by changes in the permeability, rigidity, and cytoadherence properties of the host erythrocyte. The past decade has seen enormous progress in understanding the identity and function of these exported effectors, as well as the mechanisms by which they are trafficked into the host cell. Here we review these advances, place them in the context of host manipulation by related apicomplexans, and propose key directions for future research.
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Tarr SJ, Moon RW, Hardege I, Osborne AR. A conserved domain targets exported PHISTb family proteins to the periphery of Plasmodium infected erythrocytes. Mol Biochem Parasitol 2014; 196:29-40. [PMID: 25106850 PMCID: PMC4165601 DOI: 10.1016/j.molbiopara.2014.07.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/24/2014] [Accepted: 07/28/2014] [Indexed: 11/19/2022]
Abstract
Multiple P. falciparum PHISTb proteins localise to the erythrocyte periphery. Solubility profiling indicates that these proteins associate with the red cell cytoskeleton. The PRESAN domain and a preceding N-terminal sequence is a novel targeting domain. A protein targeted to the red cell periphery is essential for parasite survival. P. knowlesi and P. vivax homologous domains also confer similar localisation.
During blood-stage infection, malaria parasites export numerous proteins to the host erythrocyte. The Poly-Helical Interspersed Sub-Telomeric (PHIST) proteins are an exported family that share a common ‘PRESAN’ domain, and include numerous members in Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi. In P. falciparum, PHIST proteins have been implicated in protein trafficking and intercellular communication. A number of PHIST proteins are essential for parasite survival. Here, we identify nine members of the PHISTb sub-class of PHIST proteins, including one protein known to be essential for parasite survival, that localise to the erythrocyte periphery. These proteins have solubility characteristics consistent with their association with the erythrocyte cytoskeleton. Together, an extended PRESAN domain, comprising the PRESAN domain and preceding sequence, form a novel targeting-domain that is sufficient to localise a protein to the erythrocyte periphery. We validate the role of this domain in RESA, thus identifying a cytoskeleton-binding domain in RESA that functions independently of its known spectrin-binding domain. Our data suggest that some PHISTb proteins may act as cross-linkers of the erythrocyte cytoskeleton. We also show for the first time that peripherally-localised PHISTb proteins are encoded in genomes of P. knowlesi and vivax indicating a conserved role for the extended PRESAN domain of these proteins in targeting to the erythrocyte periphery.
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Affiliation(s)
- Sarah J Tarr
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, UK
| | - Robert W Moon
- Division of Parasitology, MRC National Institute for Medical Research, London, UK
| | - Iris Hardege
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, UK
| | - Andrew R Osborne
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, UK.
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Elsworth B, Crabb BS, Gilson PR. Protein export in malaria parasites: an update. Cell Microbiol 2014; 16:355-63. [PMID: 24418476 DOI: 10.1111/cmi.12261] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/04/2014] [Accepted: 01/06/2014] [Indexed: 11/30/2022]
Abstract
Symptomatic malaria is caused by the infection of human red blood cells (RBCs) with Plasmodium parasites. The RBC is a peculiar environment for parasites to thrive in as they lack many of the normal cellular processes and resources present in other cells. Because of this, Plasmodium spp. have adapted to extensively remodel the host cell through the export of hundreds of proteins that have a range of functions, the best known of which are virulence-associated. Many exported parasite proteins are themselves involved in generating a novel trafficking system in the RBC that further promotes export. In this review we provide an overview of the parasite synthesized export machinery as well as recent developments in how different classes of exported proteins are recognized by this machinery.
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Affiliation(s)
- Brendan Elsworth
- Burnet Institute, 85 Commercial Road, Melbourne, Vic., 3004, Australia; Monash University, Clayton, Vic., Australia
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18
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Marti M, Spielmann T. Protein export in malaria parasites: many membranes to cross. Curr Opin Microbiol 2013; 16:445-51. [PMID: 23725671 DOI: 10.1016/j.mib.2013.04.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 04/24/2013] [Accepted: 04/30/2013] [Indexed: 11/19/2022]
Abstract
The continuous multiplication of Plasmodium parasites in red blood cells leads to a rapid increase in parasite numbers and is responsible for the disease symptoms of malaria. Survival and virulence of the parasite are linked to parasite-induced changes of the host red blood cells. These alterations require export of a large number of parasite proteins that are trafficked across multiple membranes to reach the host cell. Two classes of exported proteins are known, those with a conserved Plasmodium export element (PEXEL/HT) or those without this motif (PNEPs). Recent work has revealed new aspects of the determinants required for export of these 2 protein classes, shedding new light on the mode of trafficking during the different transport steps en route to the host cell.
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Affiliation(s)
- Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
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Rawat M, Vijay S, Gupta Y, Tiwari PK, Sharma A. Imperfect duplicate insertions type of mutations in plasmepsin V modulates binding properties of PEXEL motifs of export proteins in Indian Plasmodium vivax. PLoS One 2013; 8:e60077. [PMID: 23555891 PMCID: PMC3612065 DOI: 10.1371/journal.pone.0060077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 02/21/2013] [Indexed: 01/12/2023] Open
Abstract
Introduction Plasmepsin V (PM-V) have functionally conserved orthologues across the Plasmodium genus who's binding and antigenic processing at the PEXEL motifs for export about 200–300 essential proteins is important for the virulence and viability of the causative Plasmodium species. This study was undertaken to determine P. vivax plasmepsin V Ind (PvPM-V-Ind) PEXEL motif export pathway for pathogenicity-related proteins/antigens export thereby altering plasmodium exportome during erythrocytic stages. Method We identify and characterize Plasmodium vivax plasmepsin-V-Ind (mutant) gene by cloning, sequence analysis, in silico bioinformatic protocols and structural modeling predictions based on docking studies on binding capacity with PEXEL motifs processing in terms of binding and accessibility of export proteins. Results Cloning and sequence analysis for genetic diversity demonstrates PvPM-V-Ind (mutant) gene is highly conserved among all isolates from different geographical regions of India. Imperfect duplicate insertion types of mutations (SVSE from 246–249 AA and SLSE from 266–269 AA) were identified among all Indian isolates in comparison to P.vivax Sal-1 (PvPM-V-Sal 1) isolate. In silico bioinformatics interaction studies of PEXEL peptide and active enzyme reveal that PvPM-V-Ind (mutant) is only active in endoplasmic reticulum lumen and membrane embedding is essential for activation of plasmepsin V. Structural modeling predictions based on docking studies with PEXEL motif show significant variation in substrate protein binding of these imperfect mutations with data mined PEXEL sequences. The predicted variation in the docking score and interacting amino acids of PvPM-V-Ind (mutant) proteins with PEXEL and lopinavir suggests a modulation in the activity of PvPM-V in terms of binding and accessibility at these sites. Conclusion/Significance Our functional modeled validation of PvPM-V-Ind (mutant) imperfect duplicate insertions with data mined PEXEL sequences leading to altered binding and substrate accessibility of the enzyme makes it a plausible target to investigate export mechanisms for in silico virtual screening and novel pharmacophore designing.
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Affiliation(s)
- Manmeet Rawat
- Protein Biochemistry and Structural Biology Division, National Institute of Malaria Research (ICMR), Dwarka, New Delhi, India
- Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Sonam Vijay
- Protein Biochemistry and Structural Biology Division, National Institute of Malaria Research (ICMR), Dwarka, New Delhi, India
| | - Yash Gupta
- Department of Microbiology and Molecular Biology, National JALMA Institute for Leprosy and Other Mycobacterial Diseases (ICMR), Agra, Uttar Pradesh, India
| | - Pramod Kumar Tiwari
- Centre for Genomics, Molecular and Human Genetics, Jiwaji University, Gwalior, Madhya Pradesh, India
| | - Arun Sharma
- Protein Biochemistry and Structural Biology Division, National Institute of Malaria Research (ICMR), Dwarka, New Delhi, India
- * E-mail:
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20
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Hsiao CHC, Luisa Hiller N, Haldar K, Knoll LJ. A HT/PEXEL motif in Toxoplasma dense granule proteins is a signal for protein cleavage but not export into the host cell. Traffic 2013; 14:519-31. [PMID: 23356236 DOI: 10.1111/tra.12049] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 01/22/2013] [Accepted: 01/28/2013] [Indexed: 01/22/2023]
Abstract
Apicomplexan parasites, such as Toxoplasma gondii and Plasmodium, secrete proteins for attachment, invasion and modulation of their host cells. The host targeting (HT), also known as the Plasmodium export element (PEXEL), directs Plasmodium proteins into erythrocytes to remodel the host cell and establish infection. Bioinformatic analysis of Toxoplasma revealed a HT/PEXEL-like motif at the N-terminus of several hypothetical unknown and dense granule proteins. Hemagglutinin-tagged versions of these uncharacterized proteins show co-localization with dense granule proteins found on the parasitophorous vacuole membrane (PVM). In contrast to Plasmodium, these Toxoplasma HT/PEXEL containing proteins are not exported into the host cell. Site directed mutagenesis of the Toxoplasma HT/PEXEL motif, RxLxD/E, shows that the arginine and leucine residues are permissible for protein cleavage. Mutations within the HT/PEXEL motif that prevent protein cleavage still allow for targeting to the PV but the proteins have a reduced association with the PVM. Addition of a Myc tag before and after the cleavage site shows that processed HT/PEXEL protein has increased PVM association. These findings suggest that while Toxoplasma and Plasmodium share similar HT/PEXEL motifs, Toxoplasma HT/PEXEL containing proteins interact with but do not cross the PVM.
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Ghoneim AM. Trafficking of Plasmodium falciparum chimeric rhoptry protein with Brefeldin A. Folia Parasitol (Praha) 2013; 60:75-8. [DOI: 10.14411/fp.2013.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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22
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Tarr SJ, Cryar A, Thalassinos K, Haldar K, Osborne AR. The C-terminal portion of the cleaved HT motif is necessary and sufficient to mediate export of proteins from the malaria parasite into its host cell. Mol Microbiol 2013; 87:835-50. [PMID: 23279267 PMCID: PMC3567231 DOI: 10.1111/mmi.12133] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2012] [Indexed: 12/01/2022]
Abstract
The malaria parasite exports proteins across its plasma membrane and a surrounding parasitophorous vacuole membrane, into its host erythrocyte. Most exported proteins contain a Host Targeting motif (HT motif) that targets them for export. In the parasite secretory pathway, the HT motif is cleaved by the protease plasmepsin V, but the role of the newly generated N-terminal sequence in protein export is unclear. Using a model protein that is cleaved by an exogenous viral protease, we show that the new N-terminal sequence, normally generated by plasmepsin V cleavage, is sufficient to target a protein for export, and that cleavage by plasmepsin V is not coupled directly to the transfer of a protein to the next component in the export pathway. Mutation of the fourth and fifth positions of the HT motif, as well as amino acids further downstream, block or affect the efficiency of protein export indicating that this region is necessary for efficient export. We also show that the fifth position of the HT motif is important for plasmepsin V cleavage. Our results indicate that plasmepsin V cleavage is required to generate a new N-terminal sequence that is necessary and sufficient to mediate protein export by the malaria parasite.
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Affiliation(s)
- Sarah J Tarr
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, UK
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23
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Deponte M, Hoppe HC, Lee MC, Maier AG, Richard D, Rug M, Spielmann T, Przyborski JM. Wherever I may roam: Protein and membrane trafficking in P. falciparum-infected red blood cells. Mol Biochem Parasitol 2012; 186:95-116. [DOI: 10.1016/j.molbiopara.2012.09.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/21/2012] [Accepted: 09/24/2012] [Indexed: 11/27/2022]
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Uncovering Common Principles in Protein Export of Malaria Parasites. Cell Host Microbe 2012; 12:717-29. [DOI: 10.1016/j.chom.2012.09.010] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/16/2012] [Accepted: 09/04/2012] [Indexed: 11/21/2022]
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Bhattacharjee S, Stahelin RV, Haldar K. Host targeting of virulence determinants and phosphoinositides in blood stage malaria parasites. Trends Parasitol 2012; 28:555-62. [PMID: 23084821 DOI: 10.1016/j.pt.2012.09.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 09/19/2012] [Accepted: 09/20/2012] [Indexed: 11/25/2022]
Abstract
Blood stage malaria parasites target a 'secretome' of hundreds of proteins including virulence determinants containing a host (cell) targeting (HT) signal, to human erythrocytes. Recent studies reveal that the export mechanism is due to the HT signal binding to the lipid phosphatidylinositol-3-phosphate [PI(3)P] in the parasite endoplasmic reticulum (ER). An aspartic protease plasmepsin V which cleaves a specialized form of the HT signal was previously thought to be the export mechanism, but is now recognized as a dedicated peptidase that cleaves the signal anchor subsequent to PI(3)P binding. We discuss a model of PI(3)P-dependent targeting and PI(3)P biology of a major human pathogen.
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Affiliation(s)
- Souvik Bhattacharjee
- Center for Rare and Neglected Diseases, University of Notre Dame, 103 Galvin Life Sciences, Notre Dame, IN 46556, USA
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26
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Bhattacharjee S, Speicher KD, Stahelin RV, Speicher DW, Haldar K. PI(3)P-independent and -dependent pathways function together in a vacuolar translocation sequence to target malarial proteins to the host erythrocyte. Mol Biochem Parasitol 2012; 185:106-13. [PMID: 22828070 DOI: 10.1016/j.molbiopara.2012.07.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/10/2012] [Accepted: 07/15/2012] [Indexed: 11/18/2022]
Abstract
Malaria parasites export 'a secretome' of hundreds of proteins, including major virulence determinants, from their endoplasmic reticulum (ER), past the parasite plasma and vacuolar membranes to the host erythrocyte. The export mechanism is high affinity (nanomolar) binding of a host (cell) targeting (HT) motif RxLxE/D/Q to the lipid phosphatidylinositol 3-phosphate (PI(3)P) in the ER. Cleavage of the HT motif releases the secretory protein from the ER membrane. The HT motif is thought to be the only export signal resident in an N-terminal vacuolar translocation sequence (VTS) that quantitatively targets green fluorescent protein to the erythrocyte. We have previously shown that the R to A mutation in the HT motif, abrogates VTS binding to PI(3)P (K(d)>5 μM). We now show that remarkably, the R to A mutant is exported to the host erythrocyte, for both membrane and soluble reporters, although the efficiency of export is reduced to ~30% of that seen with a complete VTS. Mass spectrometry indicates that the R to A mutant is cleaved at sites upstream of the HT motif. Antibodies to upstream sequences confirm that aberrantly cleaved R to A protein mutant is exported to the erythrocyte. These data suggest that export mechanisms, independent of PI(3)P as well as those dependent on PI(3)P, function together in a VTS to target parasite proteins to the host erythrocyte.
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Affiliation(s)
- Souvik Bhattacharjee
- Center for Rare and Neglected Diseases, University of Notre Dame, 103 Galvin Life Sciences, Notre Dame, IN 46556, USA
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Bhattacharjee S, Stahelin RV, Speicher KD, Speicher DW, Haldar K. Endoplasmic reticulum PI(3)P lipid binding targets malaria proteins to the host cell. Cell 2012; 148:201-12. [PMID: 22265412 DOI: 10.1016/j.cell.2011.10.051] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 09/11/2011] [Accepted: 10/28/2011] [Indexed: 10/14/2022]
Abstract
Hundreds of effector proteins of the human malaria parasite Plasmodium falciparum constitute a "secretome" carrying a host-targeting (HT) signal, which predicts their export from the intracellular pathogen into the surrounding erythrocyte. Cleavage of the HT signal by a parasite endoplasmic reticulum (ER) protease, plasmepsin V, is the proposed export mechanism. Here, we show that the HT signal facilitates export by recognition of the lipid phosphatidylinositol-3-phosphate (PI(3)P) in the ER, prior to and independent of protease action. Secretome HT signals, including those of major virulence determinants, bind PI(3)P with nanomolar affinity and amino acid specificities displayed by HT-mediated export. PI(3)P-enriched regions are detected within the parasite's ER and colocalize with endogenous HT signal on ER precursors, which also display high-affinity binding to PI(3)P. A related pathogenic oomycete's HT signal export is dependent on PI(3)P binding, without cleavage by plasmepsin V. Thus, PI(3)P in the ER functions in mechanisms of secretion and pathogenesis.
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Affiliation(s)
- Souvik Bhattacharjee
- Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, IN 46556, USA
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28
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Functional analysis of the exported type IV HSP40 protein PfGECO in Plasmodium falciparum gametocytes. EUKARYOTIC CELL 2011; 10:1492-503. [PMID: 21965515 DOI: 10.1128/ec.05155-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During Plasmodium falciparum infection, host red blood cell (RBC) remodeling is required for the parasite's survival. Such modifications are mediated by the export of parasite proteins into the RBC that alter the architecture of the RBC membrane and enable cytoadherence. It is probable that some exported proteins also play a protective role against the host defense response. This may be of particular importance for the gametocyte stage of the life cycle that is responsible for malaria transmission, since the gametocyte remains in contact with blood as it proceeds through five morphological stages (I to V) during its 12-day maturation. Using microarray analysis, we identified several genes with encoded secretory or export sequences that were differentially expressed during early gametocytogenesis. One of these, PfGECO, encodes a predicted type IV heat shock protein 40 (HSP40) that we show is expressed in gametocyte stages I to IV and is exported to the RBC cytoplasm. HSPs are traditionally induced under stressful conditions to maintain homeostasis, but PfGECO expression was not increased upon heat shock, suggesting an alternate function. Targeted disruption of PfGECO indicated that the gene is not essential for gametocytogenesis in vitro, and quantitative reverse transcriptase PCR (RT-PCR) showed that there was no compensatory expression of the other type IV HSP40 genes. Although P. falciparum HSP40 members are implicated in the trafficking of proteins to the RBC surface, removal of PfGECO did not affect the targeting of other exported gametocyte proteins. This work has expanded the repertoire of known gametocyte-exported proteins to include a type IV HSP40, PfGECO.
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An erythrocyte cytoskeleton-binding motif in exported Plasmodium falciparum proteins. EUKARYOTIC CELL 2011; 10:1439-47. [PMID: 21908595 DOI: 10.1128/ec.05180-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Binding of exported malaria parasite proteins to the host cell membrane and cytoskeleton contributes to the morphological, functional, and antigenic changes seen in Plasmodium falciparum-infected erythrocytes. One such exported protein that targets the erythrocyte cytoskeleton is the mature parasite-infected erythrocyte surface antigen (MESA), which interacts with the N-terminal 30-kDa domain of protein 4.1R via a 19-residue sequence. We report here that the MESA erythrocyte cytoskeleton-binding (MEC) domain is present in at least 13 other P. falciparum proteins predicted to be exported to the host cell. An alignment of the putative cytoskeleton-binding sequences revealed a conserved aspartic acid at the C terminus that was omitted from the originally reported binding domain. Mutagenesis experiments demonstrated that this aspartic acid was required for the optimal binding of MESA to inside-out vesicles (IOVs) prepared from erythrocytes. Using pulldown assays, we characterized the binding of fragments encoding the MEC domains from PFE0040c/MESA and six other proteins (PF10_0378, PFA0675w, PFB0925w, PFD0095c, PFF1510w, and PFI1790w) to IOVs. All seven proteins bound to IOVs, with MESA showing the strongest affinity in saturation binding experiments. We further examined the interaction of the MEC domain proteins with components of the erythrocyte cytoskeleton and showed that MESA, PF10_0378, and PFA0675w coprecipitated full-length 4.1R from lysates prepared from IOVs. These data demonstrated that the MEC motif is present and functional in at least six other P. falciparum proteins that are exported to the host cell cytoplasm.
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Gaji RY, Flammer HP, Carruthers VB. Forward targeting of Toxoplasma gondii proproteins to the micronemes involves conserved aliphatic amino acids. Traffic 2011; 12:840-53. [PMID: 21438967 DOI: 10.1111/j.1600-0854.2011.01192.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Like other apicomplexan parasites, Toxoplasma gondii actively invades host cells using a combination of secretory proteins and an acto-myosin motor system. Micronemes are the first set of proteins secreted during invasion that play an essential role in host cell entry. Many microneme proteins (MICs) function in protein complexes, and each complex contains at least one protein that displays a cleavable propeptide. Although MIC propeptides have been implicated in forward targeting to micronemes, the specific amino acids involved have not been identified. It was also not known if the propeptide has a general function in MICs trafficking in T. gondii and other apicomplexans. Here we show that propeptide domains are extensively interchangeable between T. gondii MICs and also with that of Eimeria tenella MIC5 (EtMIC5), suggesting a common mechanism of function. We also performed N-terminal deletion and mutational analysis of M2AP and MIC5 propeptides to show that a valine at position +3 (relative to signal peptidase cleavage) of proM2AP and a leucine at position +1 of proMIC5 are crucial for targeting to micronemes. Valine and leucine are closely related amino acids with similar side chains, implying a similar mode of function, a notion that was confirmed by correct trafficking of TgM2AP-V/L and TgMIC5-L/V substitution mutants. Propeptides of AMA1, MIC3 and EtMIC5 have valine or leucine at or near the N-termini and mutagenesis of these conserved residues validated their role in microneme trafficking. Collectively, our findings suggest that discrete, aliphatic residues at the extreme N-termini of proMICs facilitate trafficking to the micronemes.
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Affiliation(s)
- Rajshekhar Y Gaji
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Moving in and renovating: exporting proteins from Plasmodium into host erythrocytes. Nat Rev Microbiol 2010; 8:617-21. [PMID: 20706280 DOI: 10.1038/nrmicro2420] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Malaria parasites live within erythrocytes in the host bloodstream and induce crucial changes to these cells. By so doing, they can obtain the nutrients that they require for growth and can effect the evasion and perturbation of host defences. In order to accomplish this extensive host cell remodelling, the intracellular parasite exports hundreds of proteins to commander the erythrocyte for its own purposes. An export motif, a processing enzyme that specifies protein targeting and a translocon that mediates the export of proteins from the parasite into the host erythrocyte have been identified. However, important questions remain regarding the secretory pathway and the function of the translocon. In addition, this export pathway provides potentially useful targets for the development of inhibitors to interfere with functions that are vital for the virulence and survival programmes of the parasite.
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Lee SJ, Rose JKC. Mediation of the transition from biotrophy to necrotrophy in hemibiotrophic plant pathogens by secreted effector proteins. PLANT SIGNALING & BEHAVIOR 2010; 5:769-72. [PMID: 20400849 PMCID: PMC3001586 DOI: 10.4161/psb.5.6.11778] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 03/12/2010] [Indexed: 05/20/2023]
Abstract
Hemibiotrophs, such as Phytophthora infestans, exhibit distinct phases of their life cycle: an early asymptomatic biotrophic phase and a late necrotrophic stage that is characterized by tissue degradation and disease symptoms. To date, little is known of the molecular mechanisms that promote each distinct phase, nor those that mediate the transition between the two. We hypothesized that these phytopathogens might secrete distinct classes of effector proteins that first suppress plant defense responses and associated programmed cell death (PCD), and later induce large scale necrosis. To this end, we have identified proteins that are secreted by P. infestans early or late in the infection cycle. Recently we described the characterization of SNE1, which is specifically expressed during early biotrophic growth in the host plant tomato (Solanum lycopersicum). We found that SNE1 suppresses the action of necrosis-inducing effectors (Nep1-like proteins), including PiNPP1.1 and PsojNIP, which are secreted by Phytophthora during necrotrophic growth, as well as PCD mediated by a broad spectrum of Avr-R protein interactions. This suggests that SNE1 and PiNPP1.1 act antagonistically, thereby providing a highly regulated means to control the transition from biotrophy to necrotrophy.
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Affiliation(s)
- Sang-Jik Lee
- Department of Plant Biology, Cornell University, Ithaca, NY, USA
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