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Binding and Endocytosis of Bovine Hololactoferrin by the Parasite Entamoeba histolytica. BIOMED RESEARCH INTERNATIONAL 2015; 2015:375836. [PMID: 26090404 PMCID: PMC4450225 DOI: 10.1155/2015/375836] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/11/2014] [Accepted: 09/16/2014] [Indexed: 11/26/2022]
Abstract
Entamoeba histolytica is a human parasite that requires iron (Fe) for its metabolic function and virulence. Bovine lactoferrin (B-Lf) and its peptides can be found in the digestive tract after dairy products are ingested. The aim of this study was to compare virulent trophozoites recently isolated from hamster liver abscesses with nonvirulent trophozoites maintained for more than 30 years in cultures in vitro regarding their interaction with iron-charged B-Lf (B-holo-Lf). We performed growth kinetics analyses of trophozoites in B-holo-Lf and throughout several consecutive transfers. The virulent parasites showed higher growth and tolerance to iron than nonvirulent parasites. Both amoeba variants specifically bound B-holo-Lf with a similar Kd. However, averages of 9.45 × 105 and 6.65 × 106 binding sites/cell were found for B-holo-Lf in nonvirulent and virulent amoebae, respectively. Virulent amoebae bound more efficiently to human and bovine holo-Lf, human holo-transferrin, and human and bovine hemoglobin than nonvirulent amoebae. Virulent amoebae showed two types of B-holo-Lf binding proteins. Although both amoebae endocytosed this glycoprotein through clathrin-coated vesicles, the virulent amoebae also endocytosed B-holo-Lf through a cholesterol-dependent mechanism. Both amoeba variants secreted cysteine proteases cleaving B-holo-Lf. These data demonstrate that the B-Lf endocytosis is more efficient in virulent amoebae.
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Agarwal S, Rastogi R, Gupta D, Patel N, Raje M, Mukhopadhyay A. Clathrin-mediated hemoglobin endocytosis is essential for survival of Leishmania. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1065-77. [DOI: 10.1016/j.bbamcr.2013.01.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Revised: 12/21/2012] [Accepted: 01/08/2013] [Indexed: 11/27/2022]
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Novel N-benzoyl-2-hydroxybenzamide disrupts unique parasite secretory pathway. Antimicrob Agents Chemother 2012; 56:2666-82. [PMID: 22354304 DOI: 10.1128/aac.06450-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Toxoplasma gondii is a protozoan parasite that can damage the human brain and eyes. There are no curative medicines. Herein, we describe our discovery of N-benzoyl-2-hydroxybenzamides as a class of compounds effective in the low nanomolar range against T. gondii in vitro and in vivo. Our lead compound, QQ-437, displays robust activity against the parasite and could be useful as a new scaffold for development of novel and improved inhibitors of T. gondii. Our genome-wide investigations reveal a specific mechanism of resistance to N-benzoyl-2-hydroxybenzamides mediated by adaptin-3β, a large protein from the secretory protein complex. N-Benzoyl-2-hydroxybenzamide-resistant clones have alterations of their secretory pathway, which traffics proteins to micronemes, rhoptries, dense granules, and acidocalcisomes/plant-like vacuole (PLVs). N-Benzoyl-2-hydroxybenzamide treatment also alters micronemes, rhoptries, the contents of dense granules, and, most markedly, acidocalcisomes/PLVs. Furthermore, QQ-437 is active against chloroquine-resistant Plasmodium falciparum. Our studies reveal a novel class of compounds that disrupts a unique secretory pathway of T. gondii, with the potential to be used as scaffolds in the search for improved compounds to treat the devastating diseases caused by apicomplexan parasites.
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Hirst J, D. Barlow L, Francisco GC, Sahlender DA, Seaman MNJ, Dacks JB, Robinson MS. The fifth adaptor protein complex. PLoS Biol 2011; 9:e1001170. [PMID: 22022230 PMCID: PMC3191125 DOI: 10.1371/journal.pbio.1001170] [Citation(s) in RCA: 214] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 08/30/2011] [Indexed: 11/18/2022] Open
Abstract
Adaptor protein (AP) complexes sort cargo into vesicles for transport from one membrane compartment of the cell to another. Four distinct AP complexes have been identified, which are present in most eukaryotes. We report the existence of a fifth AP complex, AP-5. Tagged AP-5 localises to a late endosomal compartment in HeLa cells. AP-5 does not associate with clathrin and is insensitive to brefeldin A. Knocking down AP-5 subunits interferes with the trafficking of the cation-independent mannose 6-phosphate receptor and causes the cell to form swollen endosomal structures with emanating tubules. AP-5 subunits can be found in all five eukaryotic supergroups, but they have been co-ordinately lost in many organisms. Concatenated phylogenetic analysis provides robust resolution, for the first time, into the evolutionary order of emergence of the adaptor subunit families, showing AP-3 as the basal complex, followed by AP-5, AP-4, and AP-1 and AP-2. Thus, AP-5 is an evolutionarily ancient complex, which is involved in endosomal sorting, and which has links with hereditary spastic paraplegia. Adaptor protein (AP) complexes facilitate the trafficking of cargo from one membrane compartment of the cell to another by recruiting other proteins to particular types of vesicles. For over 10 years, it has been assumed that there are four, and only four, distinct AP complexes in eukaryotic cells. We report the existence of a fifth AP complex, AP-5. Immunolocalisation and RNAi knockdown experiments both indicate that AP-5 is involved in trafficking proteins from endosomes towards other membranous compartments. There are genetic links between AP-5 and hereditary spastic paraplegia, a group of human genetic disorders characterised by progressive spasticity in the lower limbs. Phylogenetic analyses indicate that AP-5 was already present in the last eukaryotic common ancestor over a billion years ago.
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Affiliation(s)
- Jennifer Hirst
- University of Cambridge, Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Lael D. Barlow
- Department of Cell Biology, University of Alberta, Edmonton, Canada
| | | | - Daniela A. Sahlender
- University of Cambridge, Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Matthew N. J. Seaman
- University of Cambridge, Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Joel B. Dacks
- Department of Cell Biology, University of Alberta, Edmonton, Canada
- * E-mail: (MSR); (JBD)
| | - Margaret S. Robinson
- University of Cambridge, Cambridge Institute for Medical Research, Cambridge, United Kingdom
- * E-mail: (MSR); (JBD)
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Endocytosis and Sphingolipid Scavenging in Leishmania mexicana Amastigotes. Biochem Res Int 2011; 2012:691363. [PMID: 21941657 PMCID: PMC3177366 DOI: 10.1155/2012/691363] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 07/18/2011] [Accepted: 07/22/2011] [Indexed: 01/03/2023] Open
Abstract
Leishmania species are the causative agents of the leishmaniases, a spectrum of neglected tropical diseases. Amastigote stage parasites exist within macrophages and scavenge host factors for survival, for example, Leishmania species utilise host sphingolipid for synthesis of complex sphingolipid. In this study L. mexicana endocytosis was shown to be significantly upregulated in amastigotes, indicating that sphingolipid scavenging may be enhanced. However, inhibition of host sphingolipid biosynthesis had no significant effect on amastigote proliferation within a macrophage cell line. In addition, infection itself did not directly influence host biosynthesis. Notably, in contrast to L. major, L. mexicana amastigotes are indicated to possess a complete biosynthetic pathway suggesting that scavenged sphingolipids may be nonessential for proliferation. This suggested that Old and New World species differ in their interactions with the macrophage host. This will need to be considered when targeting the Leishmania sphingolipid biosynthetic pathway with novel therapeutics.
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de Souza W, Sant'Anna C, Cunha-e-Silva NL. Electron microscopy and cytochemistry analysis of the endocytic pathway of pathogenic protozoa. ACTA ACUST UNITED AC 2009; 44:67-124. [PMID: 19410686 DOI: 10.1016/j.proghi.2009.01.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Endocytosis is essential for eukaryotic cell survival and has been well characterized in mammal and yeast cells. Among protozoa it is also important for evading from host immune defenses and to support intense proliferation characteristic of some life cycle stages. Here we focused on the contribution of morphological and cytochemical studies to the understanding of endocytosis in Trichomonas, Giardia, Entamoeba, Plasmodium, and trypanosomatids, mainly Trypanosoma cruzi, and also Trypanosoma brucei and Leishmania.
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Affiliation(s)
- Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, Rio de Janeiro 21941-902, Brazil.
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Nevin WD, Dacks JB. Repeated secondary loss of adaptin complex genes in the Apicomplexa. Parasitol Int 2009; 58:86-94. [DOI: 10.1016/j.parint.2008.12.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 12/09/2008] [Accepted: 12/09/2008] [Indexed: 10/21/2022]
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Leishmania adaptor protein-1 subunits are required for normal lysosome traffic, flagellum biogenesis, lipid homeostasis, and adaptation to temperatures encountered in the mammalian host. EUKARYOTIC CELL 2008; 7:1256-67. [PMID: 18515754 DOI: 10.1128/ec.00090-08] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The adaptor protein-1 (AP-1) complex is involved in membrane transport between the Golgi apparatus and endosomes. In the protozoan parasite Leishmania mexicana mexicana, the AP-1 mu1 and sigma1 subunits are not required for growth at 27 degrees C but are essential for infectivity in the mammalian host. In this study, we have investigated the function of these AP-1 subunits in order to understand the molecular basis for this loss of virulence. The mu1 and sigma1 subunits were localized to late Golgi and endosome membranes of the major parasite stages. Parasite mutants lacking either AP-1 subunit lacked obvious defects in Golgi structure, endocytosis, or exocytic transport. However, these mutants displayed reduced rates of endosome-to-lysosome transport and accumulated fragmented, sterol-rich lysosomes. Defects in flagellum biogenesis were also evident in nondividing promastigote stages, and this phenotype was exacerbated by inhibitors of sterol and sphingolipid biosynthesis. Furthermore, both AP-1 mutants were hypersensitive to elevated temperature and perturbations in membrane lipid composition. The pleiotropic requirements for AP-1 in membrane trafficking and temperature stress responses explain the loss of virulence of these mutants in the mammalian host.
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Transferrin uptake in Trypanosoma cruzi is impaired by interference on cytostome-associated cytoskeleton elements and stability of membrane cholesterol, but not by obstruction of clathrin-dependent endocytosis. Exp Parasitol 2008; 119:58-66. [DOI: 10.1016/j.exppara.2007.12.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 10/22/2007] [Accepted: 12/20/2007] [Indexed: 11/23/2022]
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Silverman JM, Chan SK, Robinson DP, Dwyer DM, Nandan D, Foster LJ, Reiner NE. Proteomic analysis of the secretome of Leishmania donovani. Genome Biol 2008; 9:R35. [PMID: 18282296 PMCID: PMC2374696 DOI: 10.1186/gb-2008-9-2-r35] [Citation(s) in RCA: 229] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2007] [Revised: 01/22/2008] [Accepted: 02/18/2008] [Indexed: 12/21/2022] Open
Abstract
Analysis of Leishmania-conditioned medium resulted in the identification of 151 proteins apparently secreted by the parasitic protozoan Leishmania donovani and suggested a vesicle-based secretion system. Background Leishmania and other intracellular pathogens have evolved strategies that support invasion and persistence within host target cells. In some cases the underlying mechanisms involve the export of virulence factors into the host cell cytosol. Previous work from our laboratory identified one such candidate leishmania effector, namely elongation factor-1α, to be present in conditioned medium of infectious leishmania as well as within macrophage cytosol after infection. To investigate secretion of potential effectors more broadly, we used quantitative mass spectrometry to analyze the protein content of conditioned medium collected from cultures of stationary-phase promastigotes of Leishmania donovani, an agent of visceral leishmaniasis. Results Analysis of leishmania conditioned medium resulted in the identification of 151 proteins apparently secreted by L. donovani. Ratios reflecting the relative amounts of each leishmania protein secreted, as compared to that remaining cell associated, revealed a hierarchy of protein secretion, with some proteins secreted to a greater extent than others. Comparison with an in silico approach defining proteins potentially exported along the classic eukaryotic secretion pathway suggested that few leishmania proteins are targeted for export using a classic eukaryotic amino-terminal secretion signal peptide. Unexpectedly, a large majority of known eukaryotic exosomal proteins was detected in leishmania conditioned medium, suggesting a vesicle-based secretion system. Conclusion This analysis shows that protein secretion by L. donovani is a heterogeneous process that is unlikely to be determined by a classical amino-terminal secretion signal. As an alternative, L. donovani appears to use multiple nonclassical secretion pathways, including the release of exosome-like microvesicles.
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Affiliation(s)
- J Maxwell Silverman
- Department of Medicine (Division of Infectious Diseases), University of British Columbia, Faculty of Medicine, 2733 Heather St, Vancouver, British Columbia, V5Z 3J5, Canada.
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Dacks JB, Field MC. Evolution of the eukaryotic membrane-trafficking system: origin, tempo and mode. J Cell Sci 2007; 120:2977-85. [PMID: 17715154 DOI: 10.1242/jcs.013250] [Citation(s) in RCA: 198] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The emergence of an endomembrane system was a crucial stage in the prokaryote-to-eukaryote evolutionary transition. Recent genomic and molecular evolutionary analyses have provided insight into how this critical system arrived at its modern configuration. The apparent relative absence of prokaryotic antecedents for the endomembrane machinery contrasts with the situation for mitochondria, plastids and the nucleus. Overall, the evidence suggests an autogenous origin for the eukaryotic membrane-trafficking machinery. The emerging picture is that early eukaryotic ancestors had a complex endomembrane system, which implies that this cellular system evolved relatively rapidly after the proto-eukaryote diverged away from the other prokaryotic lines. Many of the components of the trafficking system are the result of gene duplications that have produced proteins that have similar functions but differ in their subcellular location. A proto-eukaryote possessing a very simple trafficking system could thus have evolved to near modern complexity in the last common eukaryotic ancestor (LCEA) via paralogous gene family expansion of the proteins encoding organelle identity. The descendents of this common ancestor have undergone further modification of the trafficking machinery; unicellular simplicity and multicellular complexity are the prevailing trend, but there are some remarkable counter-examples.
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Affiliation(s)
- Joel B Dacks
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
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Price HP, Stark M, Smith B, Smith DF. TbARF1 influences lysosomal function but not endocytosis in procyclic stage Trypanosoma brucei. Mol Biochem Parasitol 2007; 155:123-7. [PMID: 17681620 PMCID: PMC1964783 DOI: 10.1016/j.molbiopara.2007.06.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 06/08/2007] [Accepted: 06/19/2007] [Indexed: 11/23/2022]
Abstract
The ADP ribosylation factors (Arfs) are a highly conserved subfamily of the Ras small GTPases with crucial roles in vesicle budding and membrane trafficking. Unlike in other eukaryotes, the orthologue of Arf1 in the host bloodstream form of Trypanosoma brucei is essential for the maintenance of endocytosis. In contrast, as shown in this study, knockdown of TbARF1 by RNA interference has no effect on fluid-phase endocytosis in the insect stage of the parasite. The protein remains essential for the viability of these procyclic cells but the major effect of TbARF1-depletion is enlargement of the lysosome. Our data indicate that protein trafficking and lysosomal function are differentially regulated by multiple factors, including TbARF1, during progression through the T. brucei lifecycle.
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Affiliation(s)
- Helen P. Price
- Immunology and Infection Unit, Department of Biology, University of York, Heslington, York YO10 5YW, UK
| | - Meg Stark
- Technology Facility, Department of Biology, University of York, Heslington, York YO10 5YW, UK
| | - Barbara Smith
- Immunology and Infection Unit, Department of Biology, University of York, Heslington, York YO10 5YW, UK
| | - Deborah F. Smith
- Immunology and Infection Unit, Department of Biology, University of York, Heslington, York YO10 5YW, UK
- Corresponding author. Tel.: +44 1904 328843; fax: +44 1904 328844.
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Corrêa JR, Atella GC, Menna-Barreto RS, Soares MJ. Clathrin in Trypanosoma cruzi: In Silico Gene Identification, Isolation, and Localization of Protein Expression Sites. J Eukaryot Microbiol 2007; 54:297-302. [PMID: 17552985 DOI: 10.1111/j.1550-7408.2007.00258.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Clathrin is a scaffold protein found in different types of coated vesicles in most eukaryotic cells. Major forces that drive clathrin coat formation are the adaptor protein complexes. Trypanosoma cruzi is a flagellate protozoan that ingests macromolecules through receptor-mediated endocytosis, but the molecules involved in this process are still poorly known. Bioinformatics was used to identify proteins in the T. cruzi genome database, permitting discrimination of the genes involved in clathrin coat assembly. Clathrin expression was demonstrated in T. cruzi epimastigotes by using several experimental approaches. Western blot analysis showed a single 180-kDa protein band, which corresponds to the molecular mass of mammalian clathrin heavy chain. A flow cytometry assay demonstrated that the clathrin heavy chain was expressed in 97.74% of the cell population analyzed, with a high-fluorescence signal. Immunofluorescence observation showed labeling clustered at the flagellar pocket and Golgi complex region. Coated vesicles budding off from the flagellar pocket and the trans Golgi network membranes were identified by transmission electron microscopy. Our data demonstrate the expression of clathrin in T. cruzi epimastigotes and show the association of this polypeptide with the parasite endocytic and exocytic pathways.
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Affiliation(s)
- José R Corrêa
- Laboratório de Biologia Celular de Microrganismos, Departamento de Ultra-estrutura e Biologia Celular, Instituto Oswaldo Cruz/FIOCRUZ, 21040-900 Rio de Janeiro, RJ, Brazil
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Abstract
Trypanosomes are members of the kinetoplastida, a group of divergent protozoan parasites responsible for considerable morbidity and mortality worldwide. These organisms have highly complex life cycles requiring modification of their cell surface together with engagement of immune evasion systems to effect survival; both processes intimately involve the membrane trafficking system. The completion of three trypanosomatid and several additional protist genomes in the last few years is providing an exciting opportunity to evaluate, at the molecular level, the evolution and diversity of membrane trafficking across deep evolutionary time as well as to analyse in unprecedented detail the membrane trafficking systems of trypanosomes.
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Affiliation(s)
- Mark C Field
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
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