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Sülzen H, Began J, Dhillon A, Kereïche S, Pompach P, Votrubova J, Zahedifard F, Šubrtova A, Šafner M, Hubalek M, Thompson M, Zoltner M, Zoll S. Cryo-EM structures of Trypanosoma brucei gambiense ISG65 with human complement C3 and C3b and their roles in alternative pathway restriction. Nat Commun 2023; 14:2403. [PMID: 37105991 PMCID: PMC10140031 DOI: 10.1038/s41467-023-37988-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
African Trypanosomes have developed elaborate mechanisms to escape the adaptive immune response, but little is known about complement evasion particularly at the early stage of infection. Here we show that ISG65 of the human-infective parasite Trypanosoma brucei gambiense is a receptor for human complement factor C3 and its activation fragments and that it takes over a role in selective inhibition of the alternative pathway C5 convertase and thus abrogation of the terminal pathway. No deposition of C4b, as part of the classical and lectin pathway convertases, was detected on trypanosomes. We present the cryo-electron microscopy (EM) structures of native C3 and C3b in complex with ISG65 which reveal a set of modes of complement interaction. Based on these findings, we propose a model for receptor-ligand interactions as they occur at the plasma membrane of blood-stage trypanosomes and may facilitate innate immune escape of the parasite.
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Affiliation(s)
- Hagen Sülzen
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
- Faculty of Science, Charles University, Albertov 6, 12800, Prague 2, Czech Republic
| | - Jakub Began
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
- Department of Immunobiology, University of Lausanne, Chemin des Boveresses 155, 1066, Epalinges, Switzerland
| | - Arun Dhillon
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
| | - Sami Kereïche
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
- First Faculty of Medicine, Charles University, Albertov 4, 12800, Prague, Czech Republic
| | - Petr Pompach
- Institute of Biotechnology of the Czech Academy of Sciences, 25250, Vestec, Czech Republic
| | - Jitka Votrubova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
| | - Farnaz Zahedifard
- Department of Parasitology, Faculty of Science, Charles University Prague, Biocev, 25250, Vestec, Czech Republic
| | - Adriana Šubrtova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
| | - Marie Šafner
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
| | - Martin Hubalek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
| | - Maaike Thompson
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
- University of Antwerp, Antwerp, Belgium
- Agidens, Industrial Machinery Manufacturing, Zwijndrecht, Antwerp, Belgium
| | - Martin Zoltner
- Department of Parasitology, Faculty of Science, Charles University Prague, Biocev, 25250, Vestec, Czech Republic
| | - Sebastian Zoll
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic.
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Makarov A, Began J, Mautone IC, Pinto E, Ferguson L, Zoltner M, Zoll S, Field MC. The role of invariant surface glycoprotein 75 in xenobiotic acquisition by African trypanosomes. MICROBIAL CELL (GRAZ, AUSTRIA) 2023; 10:18-35. [PMID: 36789350 PMCID: PMC9896412 DOI: 10.15698/mic2023.02.790] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 01/02/2023] [Accepted: 01/13/2023] [Indexed: 02/05/2023]
Abstract
The surface proteins of parasitic protozoa mediate functions essential to survival within a host, including nutrient accumulation, environmental sensing and immune evasion. Several receptors involved in nutrient uptake and defence from the innate immune response have been described in African trypanosomes and, together with antigenic variation, contribute towards persistence within vertebrate hosts. Significantly, a superfamily of invariant surface glycoproteins (ISGs) populates the trypanosome surface, one of which, ISG75, is implicated in uptake of the century-old drug suramin. By CRISPR/Cas9 knockout and biophysical analysis, we show here that ISG75 directly binds suramin and mediates uptake of additional naphthol-related compounds, making ISG75 a conduit for entry of at least one structural class of trypanocidal compounds. However, ISG75 null cells present only modest attenuation of suramin sensitivity, have unaltered viability in vivo and in vitro and no alteration to suramin-invoked proteome responses. While ISG75 is demonstrated as a valid suramin cell entry pathway, we suggest the presence of additional mechanisms for suramin accumulation, further demonstrating the complexity of trypanosomatid drug interactions and potential for evolution of resistance.
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Affiliation(s)
- Alexandr Makarov
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Jakub Began
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
| | - Ileana Corvo Mautone
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Laboratorio de Moléculas Bioactivas, Departamento de Ciencias Biológicas, Universidad de la República, Paysandú 60000, Uruguay
| | - Erika Pinto
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Liam Ferguson
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Martin Zoltner
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Charles University, Faculty of Science, Department of Parasitology, Vestec, Czech Republic
| | - Sebastian Zoll
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
| | - Mark C. Field
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 Ceske Budejovice, Czech Republic
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A multifaceted strategy to improve recombinant expression and structural characterisation of a Trypanosoma invariant surface protein. Sci Rep 2022; 12:12706. [PMID: 35882923 PMCID: PMC9325691 DOI: 10.1038/s41598-022-16958-x] [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: 03/23/2022] [Accepted: 07/19/2022] [Indexed: 11/16/2022] Open
Abstract
Identification of a protein minimal fragment amenable to crystallisation can be time- and labour intensive especially if large amounts are required and the protein has a complex fold and functionally important post-translational modifications. In addition, a lack of homologues and structural information can further complicate the design of a minimal expression construct. Recombinant expression in E. coli promises high yields, low costs and fast turnover times, but falls short for many extracellular, eukaryotic proteins. Eukaryotic expression systems provide an alternative but are costly, slow and require special handling and equipment. Using a member of a structurally uncharacterized, eukaryotic receptor family as an example we employ hydrogen–deuterium exchange mass spectrometry (HDX-MS) guided construct design in conjunction with truncation scanning and targeted expression host switching to identify a minimal expression construct that can be produced with high yields and moderate costs.
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4
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Magez S, Li Z, Nguyen HTT, Pinto Torres JE, Van Wielendaele P, Radwanska M, Began J, Zoll S, Sterckx YGJ. The History of Anti-Trypanosome Vaccine Development Shows That Highly Immunogenic and Exposed Pathogen-Derived Antigens Are Not Necessarily Good Target Candidates: Enolase and ISG75 as Examples. Pathogens 2021; 10:pathogens10081050. [PMID: 34451514 PMCID: PMC8400590 DOI: 10.3390/pathogens10081050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/02/2021] [Accepted: 08/10/2021] [Indexed: 12/02/2022] Open
Abstract
Salivarian trypanosomes comprise a group of extracellular anthroponotic and zoonotic parasites. The only sustainable method for global control of these infection is through vaccination of livestock animals. Despite multiple reports describing promising laboratory results, no single field-applicable solution has been successful so far. Conventionally, vaccine research focusses mostly on exposed immunogenic antigens, or the structural molecular knowledge of surface exposed invariant immunogens. Unfortunately, extracellular parasites (or parasites with extracellular life stages) have devised efficient defense systems against host antibody attacks, so they can deal with the mammalian humoral immune response. In the case of trypanosomes, it appears that these mechanisms have been perfected, leading to vaccine failure in natural hosts. Here, we provide two examples of potential vaccine candidates that, despite being immunogenic and accessible to the immune system, failed to induce a functionally protective memory response. First, trypanosomal enolase was tested as a vaccine candidate, as it was recently characterized as a highly conserved enzyme that is readily recognized during infection by the host antibody response. Secondly, we re-addressed a vaccine approach towards the Invariant Surface Glycoprotein ISG75, and showed that despite being highly immunogenic, trypanosomes can avoid anti-ISG75 mediated parasitemia control.
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Affiliation(s)
- Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
- Department of Biochemistry and Microbiology, Ghent University, Ledeganckstraat 35, 9000 Ghent, Belgium
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Songdomunhwa-Ro 119-5, Yeonsu-Gu, Incheon 406-840, Korea;
- Correspondence:
| | - Zeng Li
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Centre of Excellence, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Belgium; (P.V.W.); (Y.G.-J.S.)
| | - Hang Thi Thu Nguyen
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
- Department of Biochemistry and Microbiology, Ghent University, Ledeganckstraat 35, 9000 Ghent, Belgium
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Songdomunhwa-Ro 119-5, Yeonsu-Gu, Incheon 406-840, Korea;
| | - Joar Esteban Pinto Torres
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
| | - Pieter Van Wielendaele
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Centre of Excellence, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Belgium; (P.V.W.); (Y.G.-J.S.)
| | - Magdalena Radwanska
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Songdomunhwa-Ro 119-5, Yeonsu-Gu, Incheon 406-840, Korea;
- Department of Biomedical Molecular Biology, Ghent University, Technologiepark Zwijnaarde 71, 9000 Ghent, Belgium
| | - Jakub Began
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo Namesti 2, 16610 Prague 6, Czech Republic; (J.B.); (S.Z.)
| | - Sebastian Zoll
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo Namesti 2, 16610 Prague 6, Czech Republic; (J.B.); (S.Z.)
| | - Yann G.-J. Sterckx
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Centre of Excellence, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Belgium; (P.V.W.); (Y.G.-J.S.)
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Umaer K, Bangs JD. Late ESCRT machinery mediates the recycling and Rescue of Invariant Surface Glycoprotein 65 in Trypanosoma brucei. Cell Microbiol 2020; 22:e13244. [PMID: 32618070 DOI: 10.1111/cmi.13244] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 12/11/2022]
Abstract
The Endosomal Sorting Complex Required for Transport machinery consists of four protein complexes (ESCRT 0-IV) and the post ESCRT ATPase Vps4. ESCRT mediates cargo delivery for lysosomal degradation via formation of multivesicular bodies. Trypanosoma brucei contains orthologues of ESCRT I-III and Vps4. Trypanosomes also have an ubiquitinylated invariant surface glycoprotein (ISG65) that is delivered to the lysosome by ESCRT, however, we previously implicated TbVps4 in rescue and recycling of ISG65. Here we use conditional silencing to investigate the role of TbVps24, a phosphoinositide-binding ESCRT III component, on protein trafficking. TbVps24 localises to the TbRab7+ late endosome, and binds PI(3,5)P2 , the product of the TbFab1 kinase, both of which also localise to late endosomes. TbVps24 silencing is lethal, and negatively affects biosynthetic trafficking of the lysosomal markers p67 and TbCathepsin L. However, the major phenotype of silencing is accelerated degradation and depletion of the surface pool of ISG65. Thus, TbVps24 silencing phenocopies that of TbVps4 in regard to ISG65 trafficking. This presents a paradox since we have previously found that depletion of TbFab1 completely blocks ISG65 turnover. We propose a model in which late ESCRT components operate at two sites, one PI(3,5)P2 -dependent (degradation) and one PI(3,5)P2 -independent (recycling), to regulate ISG65 homeostasis.
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Affiliation(s)
- Khan Umaer
- Department of Microbiology & Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York, USA
| | - James D Bangs
- Department of Microbiology & Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York, USA
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Establishment of a Standardized Vaccine Protocol for the Analysis of Protective Immune Responses During Experimental Trypanosome Infections in Mice. Methods Mol Biol 2020; 2116:721-738. [PMID: 32221951 DOI: 10.1007/978-1-0716-0294-2_42] [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] [Indexed: 12/21/2022]
Abstract
To date, trypanosomosis control in humans and animals is achieved by a combination of parasitological screening and treatment. While this approach has successfully brought down the number of reported T. b. gambiense Human African Trypanosomosis (HAT) cases, the method does not offer a sustainable solution for animal trypanosomosis (AT). The main reasons for this are (i) the worldwide distribution of AT, (ii) the wide range of insect vectors involved in transmission of AT, and (iii) the existence of a wildlife parasite reservoir that can serve as a source for livestock reinfection. Hence, in order to control livestock trypanosomosis the only viable long-term solution is an effective antitrypanosome vaccination strategy. Over the last decades, multiple vaccine approaches have been proposed. Despite repeated reports of promising experimental approaches, none of those made it to a field applicable vaccine format. This failure can in part be attributed to flaws in the experimental design that favor a positive laboratory result. This chapter provides a vaccine protocol that should allow for a proper outcome prediction in experimental anti-AT vaccine approaches.
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Umaer K, Bush PJ, Bangs JD. Rab11 mediates selective recycling and endocytic trafficking in Trypanosoma brucei. Traffic 2018; 19:406-420. [PMID: 29582527 DOI: 10.1111/tra.12565] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/15/2018] [Accepted: 03/15/2018] [Indexed: 01/21/2023]
Abstract
Trypanosoma brucei possesses a streamlined secretory system that guarantees efficient delivery to the cell surface of the critical glycosyl-phosphatidylinositol (GPI)-anchored virulence factors, variant surface glycoprotein (VSG) and transferrin receptor (TfR). Both are thought to be constitutively endocytosed and returned to the flagellar pocket via TbRab11+ recycling endosomes. We use conditional knockdown with established reporters to investigate the role of TbRab11 in specific endomembrane trafficking pathways in bloodstream trypanosomes. TbRab11 is essential. Ablation has a modest negative effect on general endocytosis, but does not affect turnover, steady state levels or surface localization of TfR. Nor are biosynthetic delivery to the cell surface and recycling of VSG affected. TbRab11 depletion also causes increased shedding of VSG into the media by formation of nanotubes and extracellular vesicles. In contrast to GPI-anchored cargo, TbRab11 depletion reduces recycling of the transmembrane invariant surface protein, ISG65, leading to increased lysosomal turnover. Thus, TbRab11 plays a critical role in recycling of transmembrane, but not GPI-anchored surface proteins. We proposed a two-step model for VSG turnover involving release of VSG-containing vesicles followed by GPI hydrolysis. Collectively, our results indicate a critical role of TbRab11 in the homeostatic maintenance of the secretory/endocytic system of bloodstream T. brucei.
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Affiliation(s)
- Khan Umaer
- Department of Microbiology & Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York
| | - Peter J Bush
- South Campus Instrument Center, School of Dental Medicine, University at Buffalo (SUNY), Buffalo, New York
| | - James D Bangs
- Department of Microbiology & Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York
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Matovu E, Kitibwa A, Picado A, Biéler S, Bessell PR, Ndung'u JM. Serological tests for gambiense human African trypanosomiasis detect antibodies in cattle. Parasit Vectors 2017; 10:546. [PMID: 29100526 PMCID: PMC5670715 DOI: 10.1186/s13071-017-2487-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/19/2017] [Indexed: 11/23/2022] Open
Abstract
Background Serological tests for gambiense human African trypanosomiasis (gHAT) detect antibodies to antigens on the cell surface of bloodstream trypanosomes. As trypanosomes that cause animal African trypanosomiasis (AAT) also express related antigens, we have evaluated two rapid diagnostic tests (RDTs) on cattle in trypanosomiasis endemic and non-endemic regions, to determine whether gHAT serological tests could also be used to screen for AAT. Methods Two RDTs, 1G RDT, made with native antigens, and p2G RDT, made with recombinant antigens, were tested on 121 cattle in a trypanosomiasis-free region, and on 312 cattle from a rhodesiense HAT and AAT endemic region. A subset of samples from the endemic region were also tested with two immune trypanolysis (TL) tests. The sensitivity of the tests was estimated by evaluating the result of the RDT on samples that were positive by both microscopy and internal transcribed spacer (ITS) PCR, whilst specificity was the result of the RDT on samples that were negative by ITS PCR and microscopy, and others from the non-endemic region. Results The specificity of the p2G RDT on cattle from the non-endemic region was 97.5% (95% CI: 93.0–99.2%), compared to only 57.9% (95% CI: 48.9–66.3%) for 1G RDT. The specificities of 1G RDT, p2G RDT and TL on endemic control cattle were 14.6% (95% CI: 9.7–21.5%), 22.6% (95% CI: 16.4–30.3%) and 68.3% (95% CI: 59.6–75.9%), respectively. The sensitivities of the tests on trypanosome positive samples were 85.1% (95% CI: 79.1–89.7%), 89.1% (95% CI: 83.7–93.0%) and 59.3% (95% CI: 51.8–66.4%), respectively. Among the same samples, 51.7% were positive by both TL and the 1G RDT. Conclusions These serological tests detect cross-reacting antibodies in cattle. The p2G RDT based on recombinant antigens had a high specificity in a non-endemic region, while the 1G RDT had a lower specificity, suggesting cross-reactivity with other pathogens. Electronic supplementary material The online version of this article (10.1186/s13071-017-2487-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Enock Matovu
- College of Veterinary Medicine, Animal Resources and Biosecurity (COVAB), Makerere University, Kampala, Uganda.
| | - Annah Kitibwa
- College of Veterinary Medicine, Animal Resources and Biosecurity (COVAB), Makerere University, Kampala, Uganda
| | - Albert Picado
- Foundation for Innovative New Diagnostics (FIND), Campus Biotech, Chemin des Mines, Geneva, Switzerland
| | - Sylvain Biéler
- Foundation for Innovative New Diagnostics (FIND), Campus Biotech, Chemin des Mines, Geneva, Switzerland
| | | | - Joseph Mathu Ndung'u
- Foundation for Innovative New Diagnostics (FIND), Campus Biotech, Chemin des Mines, Geneva, Switzerland
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Boehm CM, Obado S, Gadelha C, Kaupisch A, Manna PT, Gould GW, Munson M, Chait BT, Rout MP, Field MC. The Trypanosome Exocyst: A Conserved Structure Revealing a New Role in Endocytosis. PLoS Pathog 2017; 13:e1006063. [PMID: 28114397 PMCID: PMC5256885 DOI: 10.1371/journal.ppat.1006063] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 11/14/2016] [Indexed: 01/10/2023] Open
Abstract
Membrane transport is an essential component of pathogenesis for most infectious organisms. In African trypanosomes, transport to and from the plasma membrane is closely coupled to immune evasion and antigenic variation. In mammals and fungi an octameric exocyst complex mediates late steps in exocytosis, but comparative genomics suggested that trypanosomes retain only six canonical subunits, implying mechanistic divergence. We directly determined the composition of the Trypanosoma brucei exocyst by affinity isolation and demonstrate that the parasite complex is nonameric, retaining all eight canonical subunits (albeit highly divergent at the sequence level) plus a novel essential subunit, Exo99. Exo99 and Sec15 knockdowns have remarkably similar phenotypes in terms of viability and impact on morphology and trafficking pathways. Significantly, both Sec15 and Exo99 have a clear function in endocytosis, and global proteomic analysis indicates an important role in maintaining the surface proteome. Taken together these data indicate additional exocyst functions in trypanosomes, which likely include endocytosis, recycling and control of surface composition. Knockdowns in HeLa cells suggest that the role in endocytosis is shared with metazoan cells. We conclude that, whilst the trypanosome exocyst has novel components, overall functionality appears conserved, and suggest that the unique subunit may provide therapeutic opportunities.
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Affiliation(s)
- Cordula M. Boehm
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Samson Obado
- The Rockefeller University, 1230 York Avenue, New York, NY, United States of America
| | - Catarina Gadelha
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Alexandra Kaupisch
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Paul T. Manna
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Gwyn W. Gould
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Mary Munson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Brian T. Chait
- The Rockefeller University, 1230 York Avenue, New York, NY, United States of America
| | - Michael P. Rout
- The Rockefeller University, 1230 York Avenue, New York, NY, United States of America
| | - Mark C. Field
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
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Zoltner M, Leung KF, Alsford S, Horn D, Field MC. Modulation of the Surface Proteome through Multiple Ubiquitylation Pathways in African Trypanosomes. PLoS Pathog 2015; 11:e1005236. [PMID: 26492041 PMCID: PMC4619645 DOI: 10.1371/journal.ppat.1005236] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 09/28/2015] [Indexed: 12/29/2022] Open
Abstract
Recently we identified multiple suramin-sensitivity genes with a genome wide screen in Trypanosoma brucei that includes the invariant surface glycoprotein ISG75, the adaptin-1 (AP-1) complex and two deubiquitylating enzymes (DUBs) orthologous to ScUbp15/HsHAUSP1 and pVHL-interacting DUB1 (type I), designated TbUsp7 and TbVdu1, respectively. Here we have examined the roles of these genes in trafficking of ISG75, which appears key to suramin uptake. We found that, while AP-1 does not influence ISG75 abundance, knockdown of TbUsp7 or TbVdu1 leads to reduced ISG75 abundance. Silencing TbVdu1 also reduced ISG65 abundance. TbVdu1 is a component of an evolutionarily conserved ubiquitylation switch and responsible for rapid receptor modulation, suggesting similar regulation of ISGs in T. brucei. Unexpectedly, TbUsp7 knockdown also blocked endocytosis. To integrate these observations we analysed the impact of TbUsp7 and TbVdu1 knockdown on the global proteome using SILAC. For TbVdu1, ISG65 and ISG75 are the only significantly modulated proteins, but for TbUsp7 a cohort of integral membrane proteins, including the acid phosphatase MBAP1, that is required for endocytosis, and additional ISG-related proteins are down-regulated. Furthermore, we find increased expression of the ESAG6/7 transferrin receptor and ESAG5, likely resulting from decreased endocytic activity. Therefore, multiple ubiquitylation pathways, with a complex interplay with trafficking pathways, control surface proteome expression in trypanosomes. The mechanisms by which pathogens interact with their environment are of major importance, both for fulfilling the basic needs of the parasite and understanding immune evasion. For African trypanosomes, the surface is dominated by the variant surface glycoprotein (VSG), but recent data has demonstrated an important role for ubiquitylation in mediating turnover of invariant surface glycoproteins (ISGs) and maintaining ISG copy number independent of VSG. Further, ISG expression is required for suramin-sensitivity. Here we describe mechanisms mediating ISG turnover, uncovered using a screen for genes involved in sensitivity to suramin. These involve multiple aspects of the ubiquitylation machinery, and connect ISG turnover with additional surface proteins. Our data provide a first insight into the complexity of regulation of the ISG family, identifying further aspects to the control of a drug-sensitivity pathway in trypanosomes, and offering insights into metabolism of the parasite surface proteome.
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Affiliation(s)
- Martin Zoltner
- Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee, United Kingdom
| | - Ka Fai Leung
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Sam Alsford
- London School of Hygiene and Tropical Medicine, Keppel Street, London, United Kingdom
| | - David Horn
- Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee, United Kingdom
| | - Mark C. Field
- Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee, United Kingdom
- * E-mail:
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Gomez-Lamarca MJ, Snowdon LA, Seib E, Klein T, Bray SJ. Rme-8 depletion perturbs Notch recycling and predisposes to pathogenic signaling. J Cell Biol 2015; 210:303-18. [PMID: 26169355 PMCID: PMC4508892 DOI: 10.1083/jcb.201411001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 06/11/2015] [Indexed: 02/07/2023] Open
Abstract
The retromer-associated DNAJ protein Rme-8 is necessary for normal Notch recycling, and reductions in Rme-8 sensitize cells so that additional loss-of-sorting retromer or ESCRT-0 components have catastrophic effects. Notch signaling is a major regulator of cell fate, proliferation, and differentiation. Like other signaling pathways, its activity is strongly influenced by intracellular trafficking. Besides contributing to signal activation and down-regulation, differential fluxes between trafficking routes can cause aberrant Notch pathway activation. Investigating the function of the retromer-associated DNAJ protein Rme-8 in vivo, we demonstrate a critical role in regulating Notch receptor recycling. In the absence of Rme-8, Notch accumulated in enlarged tubulated Rab4-positive endosomes, and as a consequence, signaling was compromised. Strikingly, when the retromer component Vps26 was depleted at the same time, Notch no longer accumulated and instead was ectopically activated. Likewise, depletion of ESCRT-0 components Hrs or Stam in combination with Rme-8 also led to high levels of ectopic Notch activity. Together, these results highlight the importance of Rme-8 in coordinating normal endocytic recycling route and reveal that its absence predisposes toward conditions in which pathological Notch signaling can occur.
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Affiliation(s)
- Maria J Gomez-Lamarca
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, England, UK
| | - Laura A Snowdon
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, England, UK
| | - Ekatarina Seib
- Institute of Genetics, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Thomas Klein
- Institute of Genetics, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Sarah J Bray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, England, UK
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12
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Xhabija B, Vacratsis PO. Receptor-mediated Endocytosis 8 Utilizes an N-terminal Phosphoinositide-binding Motif to Regulate Endosomal Clathrin Dynamics. J Biol Chem 2015; 290:21676-89. [PMID: 26134565 DOI: 10.1074/jbc.m115.644757] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Indexed: 11/06/2022] Open
Abstract
Receptor-mediated endocytosis 8 (RME-8) is a DnaJ domain containing protein implicated in translocation of Hsc70 to early endosomes for clathrin removal during retrograde transport. Previously, we have demonstrated that RME-8 associates with early endosomes in a phosphatidylinositol 3-phosphate (PI(3)P)-dependent fashion. In this study, we have now identified amino acid determinants required for PI(3)P binding within a region predicted to adopt a pleckstrin homology-like fold in the N terminus of RME-8. The ability of RME-8 to associate with PI(3)P and early endosomes is largely abolished when residues Lys(17), Trp(20), Tyr(24), or Arg(26) are mutated resulting in diffuse cytoplasmic localization of RME-8 while maintaining the ability to interact with Hsc70. We also provide evidence that RME-8 PI(3)P binding regulates early endosomal clathrin dynamics and alters the steady state localization of the cation-independent mannose 6-phosphate receptor. Interestingly, RME-8 endosomal association is also regulated by the PI(3)P-binding protein SNX1, a member of the retromer complex. Wild type SNX1 restores endosomal localization of RME-8 W20A, whereas a SNX1 variant deficient in PI(3)P binding disrupts endosomal localization of wild type RME-8. These results further highlight the critical role for PI(3)P in the RME-8-mediated organizational control of various endosomal activities, including retrograde transport.
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Affiliation(s)
- Besa Xhabija
- From the Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - Panayiotis O Vacratsis
- From the Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
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13
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Sethi A, Delatte J, Foil L, Husseneder C. Protozoacidal Trojan-Horse: use of a ligand-lytic peptide for selective destruction of symbiotic protozoa within termite guts. PLoS One 2014; 9:e106199. [PMID: 25198727 PMCID: PMC4157778 DOI: 10.1371/journal.pone.0106199] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 08/04/2014] [Indexed: 11/18/2022] Open
Abstract
For novel biotechnology-based termite control, we developed a cellulose bait containing freeze-dried genetically engineered yeast which expresses a protozoacidal lytic peptide attached to a protozoa-recognizing ligand. The yeast acts as a ‘Trojan-Horse’ that kills the cellulose-digesting protozoa in the termite gut, which leads to the death of termites, presumably due to inefficient cellulose digestion. The ligand targets the lytic peptide specifically to protozoa, thereby increasing its protozoacidal efficiency while protecting non-target organisms. After ingestion of the bait, the yeast propagates in the termite's gut and is spread throughout the termite colony via social interactions. This novel paratransgenesis-based strategy could be a good supplement for current termite control using fortified biological control agents in addition to chemical insecticides. Moreover, this ligand-lytic peptide system could be used for drug development to selectively target disease-causing protozoa in humans or other vertebrates.
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Affiliation(s)
- Amit Sethi
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America
- * E-mail: (AS); (CH)
| | - Jennifer Delatte
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America
| | - Lane Foil
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America
| | - Claudia Husseneder
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America
- * E-mail: (AS); (CH)
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14
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Fleming JR, Sastry L, Crozier TWM, Napier GB, Sullivan L, Ferguson MAJ. Proteomic selection of immunodiagnostic antigens for Trypanosoma congolense. PLoS Negl Trop Dis 2014; 8:e2936. [PMID: 24922510 PMCID: PMC4055490 DOI: 10.1371/journal.pntd.0002936] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Accepted: 04/28/2014] [Indexed: 12/24/2022] Open
Abstract
Animal African Trypanosomosis (AAT) presents a severe problem for agricultural development in sub-Saharan Africa. It is caused by several trypanosome species and current means of diagnosis are expensive and impractical for field use. Our aim was to discover antigens for the detection of antibodies to Trypanosoma congolense, one of the main causative agents of AAT. We took a proteomic approach to identify potential immunodiagnostic parasite protein antigens. One hundred and thirteen proteins were identified which were selectively recognized by infected cattle sera. These were assessed for likelihood of recombinant protein expression in E. coli and fifteen were successfully expressed and assessed for their immunodiagnostic potential by ELISA using pooled pre- and post-infection cattle sera. Three proteins, members of the invariant surface glycoprotein (ISG) family, performed favorably and were then assessed using individual cattle sera. One antigen, Tc38630, evaluated blind with 77 randomized cattle sera in an ELISA assay gave sensitivity and specificity performances of 87.2% and 97.4%, respectively. Cattle immunoreactivity to this antigen diminished significantly following drug-cure, a feature helpful for monitoring the efficacy of drug treatment. Animal African Trypanosomosis (AAT) is a set of diseases whereby animals are infected with single-cell parasites that replicate in their bloodstream. The disease in cattle results in weight-loss and death, and AAT is a significant veterinary problem for sub-Saharan Africa. One of the principal trypanosome species responsible for AAT in cattle is Trypanosoma congolense and, although there are drug-treatments for these infections, current diagnostic methods are impractical for field use. Our aim was to discover protein molecules from the parasite to which infected animals make antibodies, to then make these proteins in bacteria and to subsequently demonstrate that they can be used to detect antibodies in cattle serum, thus diagnosing AAT. To discover the diagnostic proteins, we dissolved parasites in a detergent solution and applied them to beads coated with antibodies from infected cattle and to beads coated with antibodies from un-infected cattle. We then compared the proteins bound to each and selected those proteins that were at least 100-fold enriched by the infected cattle antibodies. We refined this list, according to practical and performance considerations, and settled on one protein, called Tc38630. Testing Tc38630 with cattle sera showed that it can detect about nine out of ten AAT infections.
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Affiliation(s)
- Jennifer R. Fleming
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Lalitha Sastry
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Thomas W. M. Crozier
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Grant B. Napier
- Global Alliance for Livestock Veterinary Medicines, Doherty Building, Pentlands Science Park, Edinburgh, United Kingdom
| | - Lauren Sullivan
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michael A. J. Ferguson
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, United Kingdom
- * E-mail:
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15
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Manna PT, Boehm C, Leung KF, Natesan SK, Field MC. Life and times: synthesis, trafficking, and evolution of VSG. Trends Parasitol 2014; 30:251-8. [PMID: 24731931 PMCID: PMC4007029 DOI: 10.1016/j.pt.2014.03.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 03/14/2014] [Accepted: 03/14/2014] [Indexed: 11/30/2022]
Abstract
Evasion of the acquired immune response in African trypanosomes is principally mediated by antigenic variation, the sequential expression of distinct variant surface glycoproteins (VSGs) at extremely high density on the cell surface. Sequence diversity between VSGs facilitates escape of a subpopulation of trypanosomes from antibody-mediated killing. Significant advances have increased understanding of the mechanisms underpinning synthesis and maintenance of the VSG coat. In this review, we discuss the biosynthesis, trafficking, and turnover of VSG, emphasising those unusual mechanisms that act to maintain coat integrity and to protect against immunological attack. We also highlight new findings that suggest the presence of unique or highly divergent proteins that may offer therapeutic opportunities, as well as considering aspects of VSG biology that remain to be fully explored.
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Affiliation(s)
- Paul T Manna
- Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee, DD1 5EH, UK
| | - Cordula Boehm
- Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee, DD1 5EH, UK
| | - Ka Fai Leung
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Senthil Kumar Natesan
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Mark C Field
- Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee, DD1 5EH, UK.
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16
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Freeman CL, Hesketh G, Seaman MNJ. RME-8 coordinates the activity of the WASH complex with the function of the retromer SNX dimer to control endosomal tubulation. J Cell Sci 2014; 127:2053-70. [PMID: 24643499 DOI: 10.1242/jcs.144659] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Retromer is a vital element of the endosomal protein sorting machinery and comprises two subcomplexes that operate together to sort membrane proteins (cargo) and tubulate membranes. Tubules are formed by a dimer of sorting nexins, a key component of which is SNX1. Cargo selection is mediated by the VPS35-VPS29-VPS26 trimer, which additionally recruits the WASH complex through VPS35 binding to the WASH complex subunit FAM21. Loss of function of the WASH complex leads to dysregulation of endosome tubulation, although it is unclear how this occurs. Here, we show that FAM21 also binds to the SNX1-interacting DNAJ protein RME-8. Loss of RME-8 causes altered kinetics of SNX1 membrane association and a pronounced increase in highly branched endosomal tubules. Building on previous observations from other laboratories, we show that these tubules contain membrane proteins that are dependent upon WASH complex activity for their localization to the plasma membrane. Therefore, we propose that the interaction between RME-8 and the WASH complex provides a means to coordinate the activity of the WASH complex with the membrane-tubulating function of the sorting nexins at sites where retromer-mediated endosomal protein sorting occurs.
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Affiliation(s)
- Caroline L Freeman
- University of Cambridge, Cambridge Institute for Medical Research/Department of Clinical Biochemistry, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Cambridge CB2 0XY, UK
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17
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Alsford S, Field MC, Horn D. Receptor-mediated endocytosis for drug delivery in African trypanosomes: fulfilling Paul Ehrlich's vision of chemotherapy. Trends Parasitol 2013; 29:207-12. [PMID: 23601931 DOI: 10.1016/j.pt.2013.03.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/05/2013] [Accepted: 03/06/2013] [Indexed: 12/15/2022]
Abstract
Bloodstream-form cells of Trypanosoma brucei exhibit massively increased endocytic activity relative to the insect midgut stage, enabling rapid recycling of variant surface glycoprotein and antibody clearance from the surface. In addition, recent advances have identified a role for receptor-mediated endocytosis in the uptake of the antitrypanosomal drug, suramin, via invariant surface glycoprotein 75, and in the uptake of trypanosome lytic factor 1 via haptoglobin-haemoglobin receptor. Here, we argue that receptor-mediated endocytosis represents both a validated drug target and a promising route for the delivery of novel therapeutics into trypanosomes.
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Affiliation(s)
- Sam Alsford
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
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