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Alfaro-Sifuentes R, Lares-Jiménez LF, Rojas-Hernández S, Carrasco-Yépez MM, Rojas-Ortega DA, Rodriguez-Anaya LZ, Gonzalez-Galaviz JR, Lares-Villa F. Immunogens in Balamuthia mandrillaris: a proteomic exploration. Parasitol Res 2024; 123:173. [PMID: 38536506 DOI: 10.1007/s00436-024-08193-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 03/20/2024] [Indexed: 04/04/2024]
Abstract
Balamuthia mandrillaris is the causative agent of granulomatous amoebic encephalitis, a rare and often fatal infection affecting the central nervous system. The amoeba is isolated from diverse environmental sources and can cause severe infections in both immunocompromised and immunocompetent individuals. Given the limited understanding of B. mandrillaris, our research aimed to explore its protein profile, identifying potential immunogens crucial for early granulomatous amoebic encephalitis diagnosis. Cultures of B. mandrillaris and other amoebas were grown under axenic conditions, and total amoebic extracts were obtained. Proteomic analyses, including two-dimensional electrophoresis and mass spectrometry, were performed. A 50-kDa band showed a robust recognition of antibodies from immunized BALB/c mice; peptides contained in this band were matched with elongation factor-1 alpha, which emerged as a putative key immunogen. Besides, lectin blotting revealed the presence of glycoproteins in B. mandrillaris, and confocal microscopy demonstrated the focal distribution of the 50-kDa band throughout trophozoites. Cumulatively, these observations suggest the participation of the 50-kDa band in adhesion and recognition mechanisms. Thus, these collective findings demonstrate some protein characteristics of B. mandrillaris, opening avenues for understanding its pathogenicity and developing diagnostic and therapeutic strategies.
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Affiliation(s)
- Rosalía Alfaro-Sifuentes
- Programa de Doctorado en Ciencias Especialidad en Biotecnología, Departamento de Biotecnología y Ciencias Alimentarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México.
| | - Luis Fernando Lares-Jiménez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México
| | - Saul Rojas-Hernández
- Laboratorio de Inmunología Molecular, Instituto Politécnico Nacional, Escuela Superior de Medicina, Salvador Díaz Mirón Esq. Plan de San Luis S/N, Miguel Hidalgo, Casco de Santo Tomas, Ciudad de México, México
| | | | - Diego Alexander Rojas-Ortega
- Centro de Investigación en Ciencias de La Salud (CICSA), FCS, Universidad Anáhuac México, 52786, Huixquilucan, Estado de México, México
| | | | | | - Fernando Lares-Villa
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México.
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Schichler D, Konle A, Spath EM, Riegler S, Klein A, Seleznev A, Jung S, Wuppermann T, Wetterich N, Borges A, Meyer-Natus E, Havlicek K, Pérez Cabrera S, Niedermüller K, Sajko S, Dohn M, Malzer X, Riemer E, Tumurbaatar T, Djinovic-Carugo K, Dong G, Janzen CJ, Morriswood B. Characterisation of TbSmee1 suggests endocytosis allows surface-bound cargo to enter the trypanosome flagellar pocket. J Cell Sci 2023; 136:jcs261548. [PMID: 37737012 PMCID: PMC10652038 DOI: 10.1242/jcs.261548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 09/23/2023] Open
Abstract
All endocytosis and exocytosis in the African trypanosome Trypanosoma brucei occurs at a single subdomain of the plasma membrane. This subdomain, the flagellar pocket, is a small vase-shaped invagination containing the root of the single flagellum of the cell. Several cytoskeleton-associated multiprotein complexes are coiled around the neck of the flagellar pocket on its cytoplasmic face. One of these, the hook complex, was proposed to affect macromolecule entry into the flagellar pocket lumen. In previous work, knockdown of T. brucei (Tb)MORN1, a hook complex component, resulted in larger cargo being unable to enter the flagellar pocket. In this study, the hook complex component TbSmee1 was characterised in bloodstream form T. brucei and found to be essential for cell viability. TbSmee1 knockdown resulted in flagellar pocket enlargement and impaired access to the flagellar pocket membrane by surface-bound cargo, similar to depletion of TbMORN1. Unexpectedly, inhibition of endocytosis by knockdown of clathrin phenocopied TbSmee1 knockdown, suggesting that endocytic activity itself is a prerequisite for the entry of surface-bound cargo into the flagellar pocket.
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Affiliation(s)
- Daja Schichler
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Antonia Konle
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Eva-Maria Spath
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sina Riegler
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Alexandra Klein
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Anna Seleznev
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sisco Jung
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Timothy Wuppermann
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Noah Wetterich
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Alyssa Borges
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Elisabeth Meyer-Natus
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Katharina Havlicek
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | | | - Korbinian Niedermüller
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sara Sajko
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Maximilian Dohn
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Xenia Malzer
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Emily Riemer
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Tuguldur Tumurbaatar
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Kristina Djinovic-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia
- European Molecular Biology Laboratory (EMBL) Grenoble, 38000 Grenoble, France
| | - Gang Dong
- Center for Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Christian J. Janzen
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Brooke Morriswood
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
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Jamabo M, Mahlalela M, Edkins AL, Boshoff A. Tackling Sleeping Sickness: Current and Promising Therapeutics and Treatment Strategies. Int J Mol Sci 2023; 24:12529. [PMID: 37569903 PMCID: PMC10420020 DOI: 10.3390/ijms241512529] [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: 06/13/2023] [Revised: 07/27/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
Human African trypanosomiasis is a neglected tropical disease caused by the extracellular protozoan parasite Trypanosoma brucei, and targeted for eradication by 2030. The COVID-19 pandemic contributed to the lengthening of the proposed time frame for eliminating human African trypanosomiasis as control programs were interrupted. Armed with extensive antigenic variation and the depletion of the B cell population during an infectious cycle, attempts to develop a vaccine have remained unachievable. With the absence of a vaccine, control of the disease has relied heavily on intensive screening measures and the use of drugs. The chemotherapeutics previously available for disease management were plagued by issues such as toxicity, resistance, and difficulty in administration. The approval of the latest and first oral drug, fexinidazole, is a major chemotherapeutic achievement for the treatment of human African trypanosomiasis in the past few decades. Timely and accurate diagnosis is essential for effective treatment, while poor compliance and resistance remain outstanding challenges. Drug discovery is on-going, and herein we review the recent advances in anti-trypanosomal drug discovery, including novel potential drug targets. The numerous challenges associated with disease eradication will also be addressed.
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Affiliation(s)
- Miebaka Jamabo
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
| | - Maduma Mahlalela
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
| | - Adrienne L. Edkins
- Department of Biochemistry and Microbiology, Biomedical Biotechnology Research Centre (BioBRU), Rhodes University, Makhanda 6139, South Africa;
| | - Aileen Boshoff
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
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Saito-Nakano Y, Makiuchi T, Tochikura M, Gilchrist CA, Petri WA, Nozaki T. ArfX2 GTPase Regulates Trafficking From the Trans-Golgi to Lysosomes and Is Necessary for Liver Abscess Formation in the Protozoan Parasite Entamoeba histolytica. Front Cell Infect Microbiol 2022; 11:794152. [PMID: 34976870 PMCID: PMC8719317 DOI: 10.3389/fcimb.2021.794152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 11/24/2021] [Indexed: 02/03/2023] Open
Abstract
Entamoeba histolytica is the causative agent of amoebic dysentery and liver abscess in humans. The parasitic lifestyle and the virulence of the protist require elaborate biological processes, including vesicular traffic and stress management against a variety of reactive oxygen and nitrogen species produced by the host immune response. Although the mechanisms for intracellular traffic of representative virulence factors have been investigated at molecular levels, it remains poorly understood whether and how intracellular traffic is involved in the defense against reactive oxygen and nitrogen species. Here, we demonstrate that EhArfX2, one of the Arf family of GTPases known to be involved in the regulation of vesicular traffic, was identified by comparative transcriptomic analysis of two isogenic strains: an animal-passaged highly virulent HM-1:IMSS Cl6 and in vitro maintained attenuated avirulent strain. EhArfX2 was identified as one of the most highly upregulated genes in the highly virulent strain. EhArfX2 was localized to small vesicle-like structures and largely colocalized with the marker for the trans-Golgi network SNARE, EhYkt6, but neither with the endoplasmic reticulum (ER)-resident chaperon, EhBip, nor the cis-Golgi SNARE, EhSed5, and Golgi-luminal galactosyl transferase, EhGalT. Expression of the dominant-active mutant form of EhArfX2 caused an increase in the number of lysosomes, while expression of the dominant-negative mutant led to a defect in lysosome formation and cysteine protease transport to lysosomes. Expression of the dominant-negative mutant in the virulent E. histolytica strain caused a reduction of the size of liver abscesses in a hamster model. This defect in liver abscess formation was likely at least partially attributed to reduced resistance to nitrosative, but not oxidative stress in vitro. These results showed that the EhArfX2-mediated traffic is necessary for the nitrosative stress response and virulence in the host.
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Affiliation(s)
- Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - Takashi Makiuchi
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Mami Tochikura
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - Carol A Gilchrist
- Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - William A Petri
- Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - Tomoyoshi Nozaki
- Graduate School of Medicine, The University of Tokyo, Bunkyo, Tokyo, Japan
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5
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Nihei CI, Nakanishi M. Cargo selection in the early secretory pathway of African trypanosomes. Parasitol Int 2021; 84:102379. [PMID: 34000424 DOI: 10.1016/j.parint.2021.102379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/30/2021] [Accepted: 05/06/2021] [Indexed: 11/25/2022]
Abstract
Membrane and secretory proteins are synthesized by ribosomes and then enter the endoplasmic reticulum (ER) where they undergo glycosylation and quality control for proper folding. Subsequently, proteins are transported to the Golgi apparatus and then sorted to the plasma membrane or intracellular organelles. Transport vesicles are formed at ER-exit sites (ERES) on the ER with several coat protein complexes. Cargo proteins loaded into the vesicles are selected by specific interactions with cargo receptors and/or adaptors during vesicle formation. p24 family and intracellular lectin ERGIC-53-membrane proteins are the known cargo receptors acting in the early secretory pathway (ER-Golgi). Oligomerization of the cargo receptors have been suggested to play an important role in cargo selection and sorting via posttranslational modifications in fungi and metazoans. On the other hand, the mechanisms involved in the early secretory pathway in protozoa remain unclear. In this review, we focus on Trypanosoma brucei as a representative of protozoan and discuss differences and commonalities in the molecular mechanisms of its early secretory pathway compared with other organisms.
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Affiliation(s)
- Coh-Ichi Nihei
- Institute of Microbial Chemistry, Microbial Chemistry Research Foundation (BIKAKEN), 3-14-23, Kamiosaki, Shinagawa-ku, Tokyo 141-0023, Japan.
| | - Masayuki Nakanishi
- Laboratory of Biochemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime 790-8578, Japan.
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6
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Pipaliya SV, Thompson LA, Dacks JB. The reduced ARF regulatory system in Giardia intestinalis pre-dates the transition to parasitism in the lineage Fornicata. Int J Parasitol 2021; 51:825-839. [PMID: 33848497 DOI: 10.1016/j.ijpara.2021.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 12/18/2022]
Abstract
Giardia intestinalis is an enteric pathogen with an extremely modified membrane trafficking system, lacking canonical compartments such as the Golgi, endosomes, and intermediate vesicle carriers. By comparison the fornicate relatives of Giardia possess greater endomembrane system complexity. In eukaryotes, the ADP ribosylation factor (ARF) GTPase regulatory system proteins, which consist of the small GTPase ARF1, and its guanine exchange nucleotide factors (GEFs) and GTPase activating proteins (GAPs), coordinate temporal and directional trafficking of cargo vesicles by recognizing and interacting with heterotetrameric coat complexes at pre-Golgi and post-Golgi interfaces. To understand the evolution of this regulatory system across the fornicate lineage, we have performed comparative genomic and phylogenetic analyses of the ARF GTPases, and their regulatory GAPs and GEFs in fornicate genomes and transcriptomes. Prior to our analysis of the fornicates, we first establish that the ARF GAP sub-family ArfGAP with dual PH domains (ADAP) is sparsely distributed but present in at least four eukaryotic supergroups and thus was likely present in the Last Eukaryotic Common Ancestor (LECA). Next, our collective comparative genomic and phylogenetic investigations into the ARF regulatory proteins in fornicates identify a duplication of ARF1 GTPase yielding two paralogues of ARF1F proteins, ancestral to all fornicates and present in all examined isolates of Giardia. However, the ARF GEF and ARF GAP complement is reduced compared with the LECA. This investigation shows that the system was significantly streamlined prior to the fornicate ancestor but was not further reduced concurrent with a transition into a parasitic lifestyle.
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Affiliation(s)
- Shweta V Pipaliya
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
| | - L Alexa Thompson
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada; Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada
| | - Joel B Dacks
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada; Institute of Parasitology Biology Centre, CAS v.v.i. Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
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7
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The immunogenic maturation of goat monocyte-derived dendritic cells and upregulation of toll-like receptors by five antigens of Haemonchus contortus in-vitro. Res Vet Sci 2021; 136:247-258. [PMID: 33721712 DOI: 10.1016/j.rvsc.2021.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 12/25/2022]
Abstract
Previously, it was found that several proteins of Haemonchus contortus were involved in the stimulation of the host immune system. However, the information about the selection of superlative antigens with immunogenic efficacies on host DCs is lacking. In the current study, the stimulatory effects of five recombinant proteins (elongation factor-1α, arginine kinase, ES-15, ES-24, and ADP-ribosylation factor 1) of H. contortus on the maturation of goat monocyte-derived dendritic cells (md-DCs) were reported. Recombinant proteins were purified separately in E. coli expression and incubated with isolated goat peripheral blood mononuclear cells (PBMC). Immunofluorescence assay (IFA) results confirmed the binding of these molecules to the md-DC's surface as compared to control groups. In the flow cytometry analysis, recombinant proteins induced md-DC stimulation via the up-regulation of the expression of the costimulatory molecule (CD80) and MHC-II. Quantitative RT-PCR data showed a significant increase in the expression of specific genes of the WNT and toll-like receptor (TLR) signaling pathways. The result of ELISA indicated the higher levels of cytokine (IL-10, IL-12, IFN-γ, and TNF-α) secretion in the md-DC compared to the negative (pET-32a His-Tag) and blank (PBS) control groups. The data gives valuable support in the selection of potential antigens for future studies on the immunomodulation of the host against the infection of H. contortus.
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Doñate-Macián P, Enrich-Bengoa J, Dégano IR, Quintana DG, Perálvarez-Marín A. Trafficking of Stretch-Regulated TRPV2 and TRPV4 Channels Inferred Through Interactomics. Biomolecules 2019; 9:biom9120791. [PMID: 31783610 PMCID: PMC6995547 DOI: 10.3390/biom9120791] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/19/2019] [Accepted: 11/25/2019] [Indexed: 12/11/2022] Open
Abstract
Transient receptor potential cation channels are emerging as important physiological and therapeutic targets. Within the vanilloid subfamily, transient receptor potential vanilloid 2 (TRPV2) and 4 (TRPV4) are osmo- and mechanosensors becoming critical determinants in cell structure and activity. However, knowledge is scarce regarding how TRPV2 and TRPV4 are trafficked to the plasma membrane or specific organelles to undergo quality controls through processes such as biosynthesis, anterograde/retrograde trafficking, and recycling. This review lists and reviews a subset of protein–protein interactions from the TRPV2 and TRPV4 interactomes, which is related to trafficking processes such as lipid metabolism, phosphoinositide signaling, vesicle-mediated transport, and synaptic-related exocytosis. Identifying the protein and lipid players involved in trafficking will improve the knowledge on how these stretch-related channels reach specific cellular compartments.
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Affiliation(s)
- Pau Doñate-Macián
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallés, Catalonia, Spain; (P.D.-M.); (J.E.-B.); (D.G.Q.)
- Laboratory of Molecular Physiology, Department of Experimental and Health Sciences, Pompeu Fabra University, 08003 Barcelona, Catalonia, Spain
| | - Jennifer Enrich-Bengoa
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallés, Catalonia, Spain; (P.D.-M.); (J.E.-B.); (D.G.Q.)
- Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallés, Catalonia, Spain
| | - Irene R. Dégano
- CIBER Cardiovascular Diseases (CIBERCV), Instituto de Salud Carlos III, 28029 Madrid, Spain;
- REGICOR Study Group, Cardiovascular Epidemiology and Genetics Group, IMIM (Hospital Del Mar Medical Research Institute), 08003 Barcelona, Catalonia, Spain
- Faculty of Medicine, University of Vic-Central University of Catalonia (UVic-UCC), 08500 Vic, Spain
| | - David G. Quintana
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallés, Catalonia, Spain; (P.D.-M.); (J.E.-B.); (D.G.Q.)
| | - Alex Perálvarez-Marín
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallés, Catalonia, Spain; (P.D.-M.); (J.E.-B.); (D.G.Q.)
- Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallés, Catalonia, Spain
- Correspondence: ; Tel.: +34-93-581-4504
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Veale CGL. Unpacking the Pathogen Box-An Open Source Tool for Fighting Neglected Tropical Disease. ChemMedChem 2019; 14:386-453. [PMID: 30614200 DOI: 10.1002/cmdc.201800755] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Indexed: 12/13/2022]
Abstract
The Pathogen Box is a 400-strong collection of drug-like compounds, selected for their potential against several of the world's most important neglected tropical diseases, including trypanosomiasis, leishmaniasis, cryptosporidiosis, toxoplasmosis, filariasis, schistosomiasis, dengue virus and trichuriasis, in addition to malaria and tuberculosis. This library represents an ensemble of numerous successful drug discovery programmes from around the globe, aimed at providing a powerful resource to stimulate open source drug discovery for diseases threatening the most vulnerable communities in the world. This review seeks to provide an in-depth analysis of the literature pertaining to the compounds in the Pathogen Box, including structure-activity relationship highlights, mechanisms of action, related compounds with reported activity against different diseases, and, where appropriate, discussion on the known and putative targets of compounds, thereby providing context and increasing the accessibility of the Pathogen Box to the drug discovery community.
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Affiliation(s)
- Clinton G L Veale
- School of Chemistry and Physics, Pietermaritzburg Campus, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa
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10
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Abstract
African trypanosomes cause lethal and neglected tropical diseases, known as sleeping sickness in humans and nagana in animals. Current therapies are limited, but fortunately, promising therapies are in advanced clinical and veterinary development, including acoziborole (AN5568 or SCYX-7158) and AN11736, respectively. These benzoxaboroles will likely be key to the World Health Organization's target of disease control by 2030. Their mode of action was previously unknown. We have developed a high-coverage overexpression library and use it here to explore drug mode of action in Trypanosoma brucei Initially, an inhibitor with a known target was used to select for drug resistance and to test massive parallel library screening and genome-wide mapping; this effectively identified the known target and validated the approach. Subsequently, the overexpression screening approach was used to identify the target of the benzoxaboroles, Cleavage and Polyadenylation Specificity Factor 3 (CPSF3, Tb927.4.1340). We validated the CPSF3 endonuclease as the target, using independent overexpression strains. Knockdown provided genetic validation of CPSF3 as essential, and GFP tagging confirmed the expected nuclear localization. Molecular docking and CRISPR-Cas9-based editing demonstrated how acoziborole can specifically block the active site and mRNA processing by parasite, but not host CPSF3. Thus, our findings provide both genetic and chemical validation for CPSF3 as an important drug target in trypanosomes and reveal inhibition of mRNA maturation as the mode of action of the trypanocidal benzoxaboroles. Understanding the mechanism of action of benzoxaborole-based therapies can assist development of improved therapies, as well as the prediction and monitoring of resistance, if or when it arises.
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Gadahi JA, Ehsan M, Wang S, Zhang Z, Yan R, Song X, Xu L, Li X. Recombinant protein of Haemonchus contortus small GTPase ADP-ribosylation factor 1 (HcARF1) modulate the cell mediated immune response in vitro. Oncotarget 2017; 8:112211-112221. [PMID: 29348819 PMCID: PMC5762504 DOI: 10.18632/oncotarget.22662] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 11/03/2017] [Indexed: 01/08/2023] Open
Abstract
ADP-ribosylation factors (ARFs) are members of the Ras-related small GTPase family involved in the vesicular trafficking regulation. Immunomodulatory effects of these proteinson host cell arenot being addressed yet. H. contortus small GTPase ADP-ribosylation 1 gene (HcARF1) was cloned and recombinant protein of HcARF1 (rHcARF1) was successfully expressed in Escherichia coli. Binding activity of rHcARF1 to goat PBMCs was confirmed by immunofluorescence assay (IFA) and its immunomudulatory effects on cytokine secretion, cell proliferation, cell migration and nitric oxide production (NO) were observed by co-incubation of rHcARF1. IFA results revealed that rHcARF1 could bind to the PBMCs. The interaction of rHcARF1 modulated the cytokine production, the production of IL-4, IL-10 and IL-17 was increased in a dose dependent manner, however, the IFN-γ production was significantly decreased. Cell migration and NO production were significantly increased by rHcARF1, whereas, rHcARF1 treatment significantly suppressed the proliferation of the PBMC in a dose dependent manner. Our findings showed that the rHcARF1 play important roles on the goat PBMCs.
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Affiliation(s)
- Javaid Ali Gadahi
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China.,Department of Veterinary Parasitology, Sindh Agriculture University, Tando Jam, Pakistan
| | - Muhammad Ehsan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Shuai Wang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Zhenchao Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Ruofeng Yan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Xiaokai Song
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Lixin Xu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
| | - Xiangrui Li
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China
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12
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Bayliss T, Robinson DA, Smith VC, Brand S, McElroy SP, Torrie LS, Mpamhanga C, Norval S, Stojanovski L, Brenk R, Frearson JA, Read KD, Gilbert IH, Wyatt PG. Design and Synthesis of Brain Penetrant Trypanocidal N-Myristoyltransferase Inhibitors. J Med Chem 2017; 60:9790-9806. [PMID: 29125744 PMCID: PMC5734605 DOI: 10.1021/acs.jmedchem.7b01255] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
N-Myristoyltransferase (NMT) represents a promising drug target within the parasitic protozoa Trypanosoma brucei (T. brucei), the causative agent for human African trypanosomiasis (HAT) or sleeping sickness. We have previously validated T. brucei NMT as a promising druggable target for the treatment of HAT in both stages 1 and 2 of the disease. We report on the use of the previously reported DDD85646 (1) as a starting point for the design of a class of potent, brain penetrant inhibitors of T. brucei NMT.
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Affiliation(s)
- Tracy Bayliss
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - David A Robinson
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Victoria C Smith
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Stephen Brand
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Stuart P McElroy
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Leah S Torrie
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Chido Mpamhanga
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Suzanne Norval
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Laste Stojanovski
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Ruth Brenk
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Julie A Frearson
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Kevin D Read
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Ian H Gilbert
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
| | - Paul G Wyatt
- Drug Discovery Unit, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
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13
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Yavuz S, Warren G. A role for Sar1 and ARF1 GTPases during Golgi biogenesis in the protozoan parasite Trypanosoma brucei. Mol Biol Cell 2017; 28:1782-1791. [PMID: 28495798 PMCID: PMC5491186 DOI: 10.1091/mbc.e17-03-0151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/01/2017] [Accepted: 05/05/2017] [Indexed: 11/11/2022] Open
Abstract
A single Golgi stack is duplicated and partitioned into two daughter cells during the cell cycle of the protozoan parasite Trypanosoma brucei The source of components required to generate the new Golgi and the mechanism by which it forms are poorly understood. Using photoactivatable GFP, we show that the existing Golgi supplies components directly to the newly forming Golgi in both intact and semipermeabilized cells. The movement of a putative glycosyltransferase, GntB, requires the Sar1 and ARF1 GTPases in intact cells. In addition, we show that transfer of GntB from the existing Golgi to the new Golgi can be recapitulated in semipermeabilized cells and is sensitive to the GTP analogue GTPγS. We suggest that the existing Golgi is a key source of components required to form the new Golgi and that this process is regulated by small GTPases.
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Affiliation(s)
- Sevil Yavuz
- Max F. Perutz Laboratories, University of Vienna, and Medical University of Vienna, Vienna Biocenter, Vienna A-1030, Austria
| | - Graham Warren
- Max F. Perutz Laboratories, University of Vienna, and Medical University of Vienna, Vienna Biocenter, Vienna A-1030, Austria
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14
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Roberts AJ, Fairlamb AH. The N-myristoylome of Trypanosoma cruzi. Sci Rep 2016; 6:31078. [PMID: 27492267 PMCID: PMC4974623 DOI: 10.1038/srep31078] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/12/2016] [Indexed: 01/04/2023] Open
Abstract
Protein N-myristoylation is catalysed by N-myristoyltransferase (NMT), an essential and druggable target in Trypanosoma cruzi, the causative agent of Chagas' disease. Here we have employed whole cell labelling with azidomyristic acid and click chemistry to identify N-myristoylated proteins in different life cycle stages of the parasite. Only minor differences in fluorescent-labelling were observed between the dividing forms (the insect epimastigote and mammalian amastigote stages) and the non-dividing trypomastigote stage. Using a combination of label-free and stable isotope labelling of cells in culture (SILAC) based proteomic strategies in the presence and absence of the NMT inhibitor DDD85646, we identified 56 proteins enriched in at least two out of the three experimental approaches. Of these, 6 were likely to be false positives, with the remaining 50 commencing with amino acids MG at the N-terminus in one or more of the T. cruzi genomes. Most of these are proteins of unknown function (32), with the remainder (18) implicated in a diverse range of critical cellular and metabolic functions such as intracellular transport, cell signalling and protein turnover. In summary, we have established that 0.43-0.46% of the proteome is N-myristoylated in T. cruzi approaching that of other eukaryotic organisms (0.5-1.7%).
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Affiliation(s)
- Adam J. Roberts
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Alan H. Fairlamb
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
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15
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Wright MH, Paape D, Price HP, Smith DF, Tate EW. Global Profiling and Inhibition of Protein Lipidation in Vector and Host Stages of the Sleeping Sickness Parasite Trypanosoma brucei. ACS Infect Dis 2016; 2:427-441. [PMID: 27331140 PMCID: PMC4906374 DOI: 10.1021/acsinfecdis.6b00034] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Indexed: 01/05/2023]
Abstract
The enzyme N-myristoyltransferase (NMT) catalyzes the essential fatty acylation of substrate proteins with myristic acid in eukaryotes and is a validated drug target in the parasite Trypanosoma brucei, the causative agent of African trypanosomiasis (sleeping sickness). N-Myristoylation typically mediates membrane localization of proteins and is essential to the function of many. However, only a handful of proteins are experimentally validated as N-myristoylated in T. brucei. Here, we perform metabolic labeling with an alkyne-tagged myristic acid analogue, enabling the capture of lipidated proteins in insect and host life stages of T. brucei. We further compare this with a longer chain palmitate analogue to explore the chain length-specific incorporation of fatty acids into proteins. Finally, we combine the alkynyl-myristate analogue with NMT inhibitors and quantitative chemical proteomics to globally define N-myristoylated proteins in the clinically relevant bloodstream form parasites. This analysis reveals five ARF family small GTPases, calpain-like proteins, phosphatases, and many uncharacterized proteins as substrates of NMT in the parasite, providing a global view of the scope of this important protein modification and further evidence for the crucial and pleiotropic role of NMT in the cell.
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Affiliation(s)
- Megan H. Wright
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Daniel Paape
- Centre for Immunology and Infection, Department
of Biology, University of York, York YO10 5DD, United Kingdom
| | - Helen P. Price
- Centre for Immunology and Infection, Department
of Biology, University of York, York YO10 5DD, United Kingdom
| | - Deborah F. Smith
- Centre for Immunology and Infection, Department
of Biology, University of York, York YO10 5DD, United Kingdom
| | - Edward W. Tate
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
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16
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A MORN Repeat Protein Facilitates Protein Entry into the Flagellar Pocket of Trypanosoma brucei. EUKARYOTIC CELL 2015; 14:1081-93. [PMID: 26318396 DOI: 10.1128/ec.00094-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/23/2015] [Indexed: 01/03/2023]
Abstract
The parasite Trypanosoma brucei lives in the bloodstream of infected mammalian hosts, fully exposed to the adaptive immune system. It relies on a very high rate of endocytosis to clear bound antibodies from its cell surface. All endo- and exocytosis occurs at a single site on its plasma membrane, an intracellular invagination termed the flagellar pocket. Coiled around the neck of the flagellar pocket is a multiprotein complex containing the repeat motif protein T. brucei MORN1 (TbMORN1). In this study, the phenotypic effects of TbMORN1 depletion in the mammalian-infective form of T. brucei were analyzed. Depletion of TbMORN1 resulted in a rapid enlargement of the flagellar pocket. Dextran, a polysaccharide marker for fluid phase endocytosis, accumulated inside the enlarged flagellar pocket. Unexpectedly, however, the proteins concanavalin A and bovine serum albumin did not do so, and concanavalin A was instead found to concentrate outside it. This suggests that TbMORN1 may have a role in facilitating the entry of proteins into the flagellar pocket.
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17
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Robinson DA, Wyatt PG. Identification and structure solution of fragment hits against kinetoplastid N-myristoyltransferase. Acta Crystallogr F Struct Biol Commun 2015; 71:586-93. [PMID: 25945713 PMCID: PMC4427169 DOI: 10.1107/s2053230x15003040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 02/12/2015] [Indexed: 11/30/2022] Open
Abstract
Trypanosoma brucei N-myristoyltransferase (TbNMT) is an attractive therapeutic target for the treatment of human African trypanosomiasis. Pyrazole sulfonamide (DDD85646), a potent inhibitor of TbNMT, has been identified in previous studies; however, poor central nervous system exposure restricts its use to the haemolymphatic form (stage 1) of the disease. In order to identify new chemical matter, a fragment screen was carried out by ligand-observed NMR spectroscopy, identifying hits that occupy the DDD85646 binding site. Crystal structures of hits from this assay have been obtained in complex with the closely related NMT from Leishmania major, providing a structural starting point for the evolution of novel chemical matter.
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Affiliation(s)
- David A. Robinson
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland
| | - Paul G. Wyatt
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland
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18
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Brand S, Norcross NR, Thompson S, Harrison JR, Smith VC, Robinson DA, Torrie LS, McElroy SP, Hallyburton I, Norval S, Scullion P, Stojanovski L, Simeons FRC, van Aalten D, Frearson JA, Brenk R, Fairlamb AH, Ferguson MAJ, Wyatt PG, Gilbert IH, Read KD. Lead optimization of a pyrazole sulfonamide series of Trypanosoma brucei N-myristoyltransferase inhibitors: identification and evaluation of CNS penetrant compounds as potential treatments for stage 2 human African trypanosomiasis. J Med Chem 2014; 57:9855-69. [PMID: 25412409 PMCID: PMC4269550 DOI: 10.1021/jm500809c] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
![]()
Trypanosoma bruceiN-myristoyltransferase
(TbNMT) is an attractive therapeutic
target for the treatment of human African trypanosomiasis (HAT). From
previous studies, we identified pyrazole sulfonamide, DDD85646 (1), a potent inhibitor of TbNMT. Although
this compound represents an excellent lead, poor central nervous system
(CNS) exposure restricts its use to the hemolymphatic form (stage
1) of the disease. With a clear clinical need for new drug treatments
for HAT that address both the hemolymphatic and CNS stages of the
disease, a chemistry campaign was initiated to address the shortfalls
of this series. This paper describes modifications to the pyrazole
sulfonamides which markedly improved blood–brain barrier permeability,
achieved by reducing polar surface area and capping the sulfonamide.
Moreover, replacing the core aromatic with a flexible linker significantly
improved selectivity. This led to the discovery of DDD100097 (40) which demonstrated partial efficacy in a stage 2 (CNS)
mouse model of HAT.
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Affiliation(s)
- Stephen Brand
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee , Sir James Black Centre, Dundee DD1 5EH, U.K
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19
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Wittinghofer A. Arf Proteins and Their Regulators: At the Interface Between Membrane Lipids and the Protein Trafficking Machinery. RAS SUPERFAMILY SMALL G PROTEINS: BIOLOGY AND MECHANISMS 2 2014. [PMCID: PMC7123483 DOI: 10.1007/978-3-319-07761-1_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The Arf small GTP-binding (G) proteins regulate membrane traffic and organelle structure in eukaryotic cells through a regulated cycle of GTP binding and hydrolysis. The first function identified for Arf proteins was recruitment of cytosolic coat complexes to membranes to mediate vesicle formation. However, subsequent studies have uncovered additional functions, including roles in plasma membrane signalling pathways, cytoskeleton regulation, lipid droplet function, and non-vesicular lipid transport. In contrast to other families of G proteins, there are only a few Arf proteins in each organism, yet they function specifically at many different cellular locations. Part of this specificity is achieved by formation of complexes with their guanine nucleotide-exchange factors (GEFs) and GTPase activating proteins (GAPs) that catalyse GTP binding and hydrolysis, respectively. Because these regulators outnumber their Arf substrates by at least 3-to-1, an important aspect of understanding Arf function is elucidating the mechanisms by which a single Arf protein is incorporated into different GEF, GAP, and effector complexes. New insights into these mechanisms have come from recent studies showing GEF–effector interactions, Arf activation cascades, and positive feedback loops. A unifying theme in the function of Arf proteins, carried out in conjunction with their regulators and effectors, is sensing and modulating the properties of the lipids that make up cellular membranes.
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Affiliation(s)
- Alfred Wittinghofer
- Max-Planck-Institute of Molecular Physiology, Dortmund, Nordrhein-Westfalen Germany
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20
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Roberts A, Torrie L, Wyllie S, Fairlamb A. Biochemical and genetic characterization of Trypanosoma cruzi N-myristoyltransferase. Biochem J 2014; 459:323-32. [PMID: 24444291 PMCID: PMC3969225 DOI: 10.1042/bj20131033] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 01/20/2014] [Accepted: 01/21/2014] [Indexed: 12/20/2022]
Abstract
Co- and post-translational N-myristoylation is known to play a role in the correct subcellular localization of specific proteins in eukaryotes. The enzyme that catalyses this reaction, NMT (N-myristoyltransferase), has been pharmacologically validated as a drug target in the African trypanosome, Trypanosoma brucei. In the present study, we evaluate NMT as a potential drug target in Trypanosoma cruzi, the causative agent of Chagas' disease, using chemical and genetic approaches. Replacement of both allelic copies of TcNMT (T. cruzi NMT) was only possible in the presence of a constitutively expressed ectopic copy of the gene, indicating that this gene is essential for survival of T. cruzi epimastigotes. The pyrazole sulphonamide NMT inhibitor DDD85646 is 13-23-fold less potent against recombinant TcNMT than TbNMT (T. brucei NMT), with Ki values of 12.7 and 22.8 nM respectively, by scintillation proximity or coupled assay methods. DDD85646 also inhibits growth of T. cruzi epimastigotes (EC50=6.9 μM), but is ~1000-fold less potent than that reported for T. brucei. On-target activity is demonstrated by shifts in cell potency in lines that over- and under-express NMT and by inhibition of intracellular N-myristoylation of several proteins in a dose-dependent manner. Collectively, our findings suggest that N-myristoylation is an essential and druggable target in T. cruzi.
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Key Words
- chagas’ disease
- click chemistry
- drug target
- n-myristoylation
- trypanosoma cruzi
- validation
- cap5.5, cytoskeleton-associated protein 5.5
- dig, digoxigenin
- dko, double knockout
- dmem, dulbecco’s modified eagle’s medium
- hyg, hygromycin phosphotransferase
- nmt, n-myristoyltransferase
- nmtoe, nmt overexpressor
- pac, puromycin n-acetyltransferase
- rth/fbs, rpmi 1640 medium supplemented with trypticase, haemin, hepes and 10% heat-inactivated fbs
- sko, single knockout
- tbnmt, trypanosoma brucei nmt
- tcep, tris-(2-carboxyethyl)phosphine
- tcnmt, trypanosoma cruzi nmt
- tctryr, trypanosoma cruzi trypanothione reductase
- wt, wild-type
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Affiliation(s)
- Adam J. Roberts
- *Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Leah S. Torrie
- *Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Susan Wyllie
- *Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Alan H. Fairlamb
- *Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
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21
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MacLean L, Myburgh E, Rodgers J, Price HP. Imaging African trypanosomes. Parasite Immunol 2014; 35:283-94. [PMID: 23790101 PMCID: PMC3992894 DOI: 10.1111/pim.12046] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 06/18/2013] [Indexed: 12/18/2022]
Abstract
Trypanosoma brucei are extracellular kinetoplastid parasites transmitted by the blood-sucking tsetse fly. They are responsible for the fatal disease human African trypanosomiasis (HAT), also known as sleeping sickness. In late-stage infection, trypanosomes cross the blood–brain barrier (BBB) and invade the central nervous system (CNS) invariably leading to coma and death if untreated. There is no available vaccine and current late-stage HAT chemotherapy consists of either melarsoprol, which is highly toxic causing up to 8% of deaths, or nifurtimox–eflornithine combination therapy (NECT), which is costly and difficult to administer. There is therefore an urgent need to identify new late-stage HAT drug candidates. Here, we review how current imaging tools, ranging from fluorescent confocal microscopy of live immobilized cells in culture to whole-animal imaging, are providing insight into T. brucei biology, parasite-host interplay, trypanosome CNS invasion and disease progression. We also consider how imaging tools can be used for candidate drug screening purposes that could lead to new chemotherapies.
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Affiliation(s)
- L MacLean
- Centre for Immunology and Infection, Department of Biology/Hull York Medical School, University of York, Heslington, York, UK.
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22
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Tate EW, Bell AS, Rackham MD, Wright MH. N-Myristoyltransferase as a potential drug target in malaria and leishmaniasis. Parasitology 2014; 141:37-49. [PMID: 23611109 DOI: 10.1017/s0031182013000450] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Infections caused by protozoan parasites are among the most widespread and intractable transmissible diseases affecting the developing world, with malaria and leishmaniasis being the most costly in terms of morbidity and mortality. Although new drugs are urgently required against both diseases in the face of ever-rising resistance to frontline therapies, very few candidates passing through development pipelines possess a known and novel mode of action. Set in the context of drugs currently in use and under development, we present the evidence for N-myristoyltransferase (NMT), an enzyme that N-terminally lipidates a wide range of specific target proteins through post-translational modification, as a potential drug target in malaria and the leishmaniases. We discuss the limitations of current knowledge regarding the downstream targets of this enzyme in protozoa, and our recent progress towards potent cell-active NMT inhibitors against the most clinically-relevant species of parasite. Finally, we outline the next steps required in terms of both tools to understand N-myristoylation in protozoan parasites, and the generation of potential development candidates based on the output of our recently-reported high-throughput screens.
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Affiliation(s)
- Edward W Tate
- Department of Chemistry, Institute of Chemical Biology, Imperial College London, London SW7 2AZ, UK
| | - Andrew S Bell
- Department of Chemistry, Institute of Chemical Biology, Imperial College London, London SW7 2AZ, UK
| | - Mark D Rackham
- Department of Chemistry, Institute of Chemical Biology, Imperial College London, London SW7 2AZ, UK
| | - Megan H Wright
- Department of Chemistry, Institute of Chemical Biology, Imperial College London, London SW7 2AZ, UK
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23
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Adung'a VO, Gadelha C, Field MC. Proteomic analysis of clathrin interactions in trypanosomes reveals dynamic evolution of endocytosis. Traffic 2013; 14:440-57. [PMID: 23305527 DOI: 10.1111/tra.12040] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 01/07/2013] [Accepted: 01/10/2012] [Indexed: 01/09/2023]
Abstract
Endocytosis is a vital cellular process maintaining the cell surface, modulating signal transduction and facilitating nutrient acquisition. In metazoa, multiple endocytic modes are recognized, but for many unicellular organisms the process is likely dominated by the ancient clathrin-mediated pathway. The endocytic system of the highly divergent trypanosomatid Trypanosoma brucei exhibits many unusual features, including a restricted site of internalization, dominance of the plasma membrane by GPI-anchored proteins, absence of the AP2 complex and an exceptionally high rate. Here we asked if the proteins subtending clathrin trafficking in trypanosomes are exclusively related to those of higher eukaryotes or if novel, potentially taxon-specific proteins operate. Co-immunoprecipitation identified twelve T. brucei clathrin-associating proteins (TbCAPs), which partially colocalized with clathrin. Critically, eight TbCAPs are restricted to trypanosomatid genomes and all of these are required for robust cell proliferation. A subset, TbCAP100, TbCAP116, TbCAP161 and TbCAP334, were implicated in distinct endocytic steps by detailed analysis of knockdown cells. Coupled with the absence of orthologs for many metazoan and fungal endocytic factors, these data suggest that clathrin interactions in trypanosomes are highly lineage-specific, and indicate substantial evolutionary diversity within clathrin-mediated endocytosis mechanisms across the eukaryotes.
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Affiliation(s)
- Vincent O Adung'a
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
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24
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Oyola SO, Evans KJ, Smith TK, Smith BA, Hilley JD, Mottram JC, Kaye PM, Smith DF. Functional analysis of Leishmania cyclopropane fatty acid synthetase. PLoS One 2012; 7:e51300. [PMID: 23251490 PMCID: PMC3519623 DOI: 10.1371/journal.pone.0051300] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 10/31/2012] [Indexed: 01/14/2023] Open
Abstract
The single gene encoding cyclopropane fatty acid synthetase (CFAS) is present in Leishmania infantum, L. mexicana and L. braziliensis but absent from L. major, a causative agent of cutaneous leishmaniasis. In L. infantum, usually causative agent of visceral leishmaniasis, the CFAS gene is transcribed in both insect (extracellular) and host (intracellular) stages of the parasite life cycle. Tagged CFAS protein is stably detected in intracellular L. infantum but only during the early log phase of extracellular growth, when it shows partial localisation to the endoplasmic reticulum. Lipid analyses of L. infantum wild type, CFAS null and complemented parasites detect a low abundance CFAS-dependent C19Δ fatty acid, characteristic of a cyclopropanated species, in wild type and add-back cells. Sub-cellular fractionation studies locate the C19Δ fatty acid to both ER and plasma membrane-enriched fractions. This fatty acid is not detectable in wild type L. major, although expression of the L. infantum CFAS gene in L. major generates cyclopropanated fatty acids, indicating that the substrate for this modification is present in L. major, despite the absence of the modifying enzyme. Loss of the L. infantum CFAS gene does not affect extracellular parasite growth, phagocytosis or early survival in macrophages. However, while endocytosis is also unaffected in the extracellular CFAS nulls, membrane transporter activity is defective and the null parasites are more resistant to oxidative stress. Following infection in vivo, L. infantum CFAS nulls exhibit lower parasite burdens in both the liver and spleen of susceptible hosts but it has not been possible to complement this phenotype, suggesting that loss of C19Δ fatty acid may lead to irreversible changes in cell physiology that cannot be rescued by re-expression. Aberrant cyclopropanation in L. major decreases parasite virulence but does not influence parasite tissue tropism.
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Affiliation(s)
- Samuel O Oyola
- Centre for Immunology and Infection, Department of Biology/Hull York Medical School, University of York, York, United Kingdom
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25
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Adung'a VO, Field MC. TbFRP, a novel FYVE-domain containing phosphoinositide-binding Ras-like GTPase from trypanosomes. Exp Parasitol 2012; 133:255-64. [PMID: 23220323 PMCID: PMC3593210 DOI: 10.1016/j.exppara.2012.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 11/15/2012] [Indexed: 01/06/2023]
Abstract
Ras-like small GTPases are regulatory proteins that control multiple aspects of cellular function, and are particularly prevalent in vesicular transport. A proportion of GTPase paralogs appear restricted to certain eukaryote lineages, suggesting roles specific to a restricted lineage, and hence potentially reflecting adaptation to individual lifestyles or ecological niche. Here we describe the role of a GTPase, TbFRP, a FYVE domain N-terminally fused to a Ras-like GTPase, originally identified in Trypanosoma brucei. As FYVE-domains specifically bind phosphoinositol 3-phosphate (PI3P), which associates with endosomes, we suggest that TbFRP may unite phosphoinositide and small G protein endosomal signaling in trypanosomatids. TbFRP orthologs are present throughout the Euglenazoa suggesting that FRP has functions throughout the group. We show that the FYVE domain of TbFRP is functional in PI3P-dependent membrane targeting and localizes at the endosomal region. Further, while TbFRP is apparently non-essential, knockdown and immunochemical evidence indicates that TbFRP is rapidly cleaved upon synthesis, releasing the GTPase and FYVE-domains. Finally, TbFRP expression at both mRNA and protein levels is cell density-dependent. Together, these data suggest that TbFRP is an endocytic GTPase with a highly unusual mechanism of action that involves proteolysis of the nascent protein and membrane targeting via PI3P.
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Affiliation(s)
- Vincent O Adung'a
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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Rampoldi F, Sandhoff R, Owen RW, Gröne HJ, Porubsky S. A new, robust, and nonradioactive approach for exploring N-myristoylation. J Lipid Res 2012; 53:2459-68. [PMID: 22829651 DOI: 10.1194/jlr.d026997] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myristoyl-CoA (CoA):protein N-myristoyltransferase (NMT) catalyzes protein modification through covalent attachment of a C14 fatty acid (myristic acid) to the N-terminal glycine of proteins, thus promoting protein-protein and protein-membrane interactions. NMT is essential for the viability of numerous human pathogens and is also up-regulated in several tumors. Here we describe a new, nonradioactive, ELISA-based method for measuring NMT activity. After the NMT-catalyzed reaction between a FLAG-tagged peptide and azido-dodecanoyl-CoA (analog of myristoyl-CoA), the resulting azido-dodecanoyl-peptide-FLAG was coupled to phosphine-biotin by Staudinger ligation, captured by plate-bound anti-FLAG antibodies and detected by streptavidin-peroxidase. The assay was validated with negative controls (including inhibitors), corroborated by HPLC analysis, and demonstrated to function with fresh or frozen tissues. Recombinant murine NMT1 and NMT2 were characterized using this new method. This versatile assay is applicable for exploring recombinant NMTs with regard to their activity, substrate specificity, and possible inhibitors as well as for measuring NMT-activity in tissues.
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Affiliation(s)
- Francesca Rampoldi
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Heidelberg, Germany
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Price HP, Hodgkinson MR, Wright MH, Tate EW, Smith BA, Carrington M, Stark M, Smith DF. A role for the vesicle-associated tubulin binding protein ARL6 (BBS3) in flagellum extension in Trypanosoma brucei. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1823:1178-91. [PMID: 22609302 PMCID: PMC3793860 DOI: 10.1016/j.bbamcr.2012.05.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 04/23/2012] [Accepted: 05/05/2012] [Indexed: 11/17/2022]
Abstract
The small GTPase Arl6 is implicated in the ciliopathic human genetic disorder Bardet-Biedl syndrome, acting at primary cilia in recruitment of the octomeric BBSome complex, which is required for specific trafficking events to and from the cilium in eukaryotes. Here we describe functional characterisation of Arl6 in the flagellated model eukaryote Trypanosoma brucei, which requires motility for viability. Unlike human Arl6 which has a ciliary localisation, TbARL6 is associated with electron-dense vesicles throughout the cell body following co-translational modification by N-myristoylation. Similar to the related protein ARL-3A in T. brucei, modulation of expression of ARL6 by RNA interference does not prevent motility but causes a significant reduction in flagellum length. Tubulin is identified as an ARL6 interacting partner, suggesting that ARL6 may act as an anchor between vesicles and cytoplasmic microtubules. We provide evidence that the interaction between ARL6 and the BBSome is conserved in unicellular eukaryotes. Overexpression of BBS1 leads to translocation of endogenous ARL6 to the site of exogenous BBS1 at the flagellar pocket. Furthermore, a combination of BBS1 overexpression and ARL6 RNAi has a synergistic inhibitory effect on cell growth. Our findings indicate that ARL6 in trypanosomes contributes to flagellum biogenesis, most likely through an interaction with the BBSome.
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Key Words
- arf, adp-ribosylation factor
- arl, adp-ribosylation factor-like
- arl6ip, arl6 interacting protein
- bbs, bardet–biedl syndrome
- bbs1, bardet–biedl syndrome 1 protein
- bsf, bloodstream form
- cona, concanavalin a
- gef, guanine nucleotide exchange factor
- gpcr, g-protein coupled receptor
- hrg4, human retinal gene 4
- ift, intraflagellar transport
- itc, isothermal titration calorimetry
- mant, n-methylanthraniloyl
- map2, microtubule associated protein 2
- nes, nuclear export signal
- nls, nuclear localisation signal
- nmt, myristoyl-coa:protein n-myristoyltransferase
- pcf, procyclic form
- pcm1, pericentriolar material 1
- pfr, paraflagellar rod
- pm, plasma membrane
- rnai, rna interference
- rp2, retinitis pigmentosa protein 2
- tap, tandem affinity purification
- tiem, transmission immuno-electron microscopy
- trypanosoma brucei
- arl6
- bbsome
- bbs1
- flagellum
- tubulin
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Affiliation(s)
- Helen P Price
- Centre for Immunology and Infection, Department of Biology, University of York, Heslington, York YO10 5YW, UK.
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ARF family G proteins and their regulators: roles in membrane transport, development and disease. Nat Rev Mol Cell Biol 2011; 12:362-75. [PMID: 21587297 PMCID: PMC3245550 DOI: 10.1038/nrm3117] [Citation(s) in RCA: 669] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ADP-ribosylation factor (ARF) family of guanine-nucleotide-binding (G) proteins, including the ARF proteins, ARF-like (ARL) proteins and SAR1, regulates membrane traffic and organelle structure, and each family member is regulated through a cycle of GTP binding and GTP hydrolysis, which activate and inactivate, respectively, the G protein. Traditionally, ARFs have been characterized for their immediate effects in the recruitment of coat proteins to drive cargo sorting, the recruitment of enzymes that can alter membrane lipid composition and the regulation of cytoskeletal factors. Now, new roles for ARFs have been discovered at the Golgi complex, for example in driving lipid transport. ARL proteins are also being increasingly linked to coordination of trafficking with cytoskeletal processes, for example during ciliogenesis. There is particular interest in the mechanisms that control recruitment of the ARF guanine nucleotide exchange factors (GEFs) that mediate GTP binding to ARFs and, in the case of the cytohesin (also known as ARNO) GEF, membrane recruitment is coupled to relief of autoinhibition. GEFs such as cytohesin may also participate in a cascade of activation between particular pairs of ARFs. Traditionally, G protein signalling has been viewed as a linear pathway, with the GDP-bound form of an ARF protein being inactive; however, more recent studies have highlighted novel roles for these GDP-bound forms and have also shown that GEFs and GTPase-activating proteins (GAPs) themselves can engage in distinct signalling responses through scaffolding functions.
The ADP-ribosylation factor (ARF) and ARF-like (ARL) family of G proteins, which are known to regulate membrane traffic and organelle structure, are emerging as regulators of diverse processes, including lipid and cytoskeletal transport. Although traditionally viewed as part of a linear signalling pathway, ARFs and their regulators must now be considered to exist within functional networks, in which both the 'inactive' ARF and the regulators themselves can mediate distinct effects. Members of the ADP-ribosylation factor (ARF) family of guanine-nucleotide-binding (G) proteins, including the ARF-like (ARL) proteins and SAR1, regulate membrane traffic and organelle structure by recruiting cargo-sorting coat proteins, modulating membrane lipid composition, and interacting with regulators of other G proteins. New roles of ARF and ARL proteins are emerging, including novel functions at the Golgi complex and in cilia formation. Their function is under tight spatial control, which is mediated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) that catalyse GTP exchange and hydrolysis, respectively. Important advances are being gained in our understanding of the functional networks that are formed not only by the GEFs and GAPs themselves but also by the inactive forms of the ARF proteins.
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FYVE-dependent endosomal targeting of an arrestin-related protein in amoeba. PLoS One 2010; 5:e15249. [PMID: 21179207 PMCID: PMC3001460 DOI: 10.1371/journal.pone.0015249] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 11/06/2010] [Indexed: 01/04/2023] Open
Abstract
Background Visual and β-arrestins are scaffolding proteins involved in the regulation of receptor-dependent intracellular signaling and their trafficking. The arrestin superfamilly includes several arrestin domain-containing proteins and the structurally related protein Vps26. In Dictyostelium discoideum, the arrestin-domain containing proteins form a family of six members, namely AdcA to -F. In contrast to canonical arrestins, Dictyostelium Adc proteins show a more complex architecture, as they possess, in addition to the arrestin core, other domains, such as C2, FYVE, LIM, MIT and SAM, which potentially mediate selective interactions with either lipids or proteins. Methodology and Principal Findings A detailed analysis of AdcA has been performed. AdcA extends on both sides of the arrestin core, in particular by a FYVE domain which mediates selective interactions with PI(3)P, as disclosed by intrinsic fluorescence measurements and lipid overlay assays. Localization studies showed an enrichment of tagged- and endogenous AdcA on the rim of early macropinosomes and phagosomes. This vesicular distribution relies on a functional FYVE domain. Our data also show that the arrestin core binds the ADP-ribosylation factor ArfA, the unique amoebal Arf member, in its GDP-bound conformation. Significance This work describes one of the 6 arrestin domain-containing proteins of Dictyostelium, a novel and atypical member of the arrestin clan. It provides the basis for a better understanding of arrestin-related protein involvement in trafficking processes and for further studies on the expanding roles of arrestins in eukaryotes.
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Cook WJ, Smith CD, Senkovich O, Holder AA, Chattopadhyay D. Structure of Plasmodium falciparum ADP-ribosylation factor 1. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1426-31. [PMID: 21045287 DOI: 10.1107/s1744309110036997] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 09/15/2010] [Indexed: 12/12/2022]
Abstract
Vesicular trafficking may play a crucial role in the pathogenesis and survival of the malaria parasite. ADP-ribosylation factors (ARFs) are among the major components of vesicular trafficking pathways in eukaryotes. The crystal structure of ARF1 GTPase from Plasmodium falciparum has been determined in the GDP-bound conformation at 2.5 Å resolution and is compared with the structures of mammalian ARF1s.
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Affiliation(s)
- William J Cook
- University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Abstract
The Arf-like (Arl) small GTPases have a diverse range of functions in the eukaryotic cell. Metazoan Arl2 acts as a regulator of microtubule biogenesis, binding to the tubulin-specific chaperone cofactor D. Arl2 also has a mitochondrial function through its interactions with BART and ANT-1, the only member of the Ras superfamily to be found in this organelle to date. In the present study, we describe characterization of the Arl2 orthologue in the protozoan parasite Trypanosoma brucei. Modulation of TbARL2 expression in bloodstream form parasites by RNA interference (RNAi) causes inhibition of cleavage furrow formation, resulting in a severe defect in cytokinesis and the accumulation of multinucleated cells. RNAi of TbARL2 also results in loss of acetylated alpha-tubulin but not of total -tubulin from cellular microtubules. While overexpression of TbARL2(myc) also leads to a defect in cytokinesis, an excess of untagged protein has no effect on cell division, demonstrating the importance of the extreme C-terminus in correct function. TbARL2 overexpressing cells (either myc-tagged or untagged) have an increase in acetylated -tubulin. Our data indicate that Arl2 has a fundamentally conserved role in trypanosome microtubule biogenesis that correlates with -tubulin acetylation.
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Brighouse A, Dacks JB, Field MC. Rab protein evolution and the history of the eukaryotic endomembrane system. Cell Mol Life Sci 2010; 67:3449-65. [PMID: 20582450 PMCID: PMC2943070 DOI: 10.1007/s00018-010-0436-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 05/28/2010] [Accepted: 06/09/2010] [Indexed: 12/20/2022]
Abstract
Spectacular increases in the quantity of sequence data genome have facilitated major advances in eukaryotic comparative genomics. By exploiting homology with classical model organisms, this makes possible predictions of pathways and cellular functions currently impossible to address in intractable organisms. Echoing realization that core metabolic processes were established very early following evolution of life on earth, it is now emerging that many eukaryotic cellular features, including the endomembrane system, are ancient and organized around near-universal principles. Rab proteins are key mediators of vesicle transport and specificity, and via the presence of multiple paralogues, alterations in interaction specificity and modification of pathways, contribute greatly to the evolution of complexity of membrane transport. Understanding system-level contributions of Rab proteins to evolutionary history provides insight into the multiple processes sculpting cellular transport pathways and the exciting challenges that we face in delving further into the origins of membrane trafficking specificity.
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Affiliation(s)
- Andrew Brighouse
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP UK
- King’s College London School of Medicine, Hodgkin Building, London, SE1 1UL UK
| | - Joel B. Dacks
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7 Canada
| | - Mark C. Field
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP UK
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Fleming JR, Dawson A, Hunter WN. Crystal structure of Leishmania major ADP-ribosylation factor-like 1 and a classification of related GTPase family members in this Kinetoplastid. Mol Biochem Parasitol 2010; 174:141-4. [PMID: 20801163 DOI: 10.1016/j.molbiopara.2010.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 08/11/2010] [Accepted: 08/13/2010] [Indexed: 12/24/2022]
Abstract
ADP-ribosylation factor-like (ARL) proteins are small GTPases that undergo conformational changes upon nucleotide binding, and which regulate the affinity of ARLs for binding other proteins, lipids or membranes. There is a paucity of structural data on this family of proteins in the Kinetoplastida, despite studies implicating them in key events related to vesicular transport and regulation of microtubule-dependent processes. The crystal structure of Leishmania major ARL1 in complex with GDP has been determined to 2.1 Å resolution and reveals a high degree of structural conservation with human ADP-ribosylation factor 1 (ARF1). Putative L. major and Trypanosoma brucei ARF/ARL family members have been classified based on structural considerations, amino acid sequence conservation combined with functional data on Kinetoplastid and human orthologues. This classification may guide future studies designed to elucidate the function of specific family members.
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Affiliation(s)
- Jennifer R Fleming
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, UK
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Wang YN, Wang M, Field MC. Trypanosoma brucei: trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression. Exp Parasitol 2010; 125:208-21. [PMID: 20109450 PMCID: PMC2877885 DOI: 10.1016/j.exppara.2010.01.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 01/13/2010] [Accepted: 01/18/2010] [Indexed: 12/22/2022]
Abstract
In Trypanosoma brucei the GPI-anchored variant surface glycoprotein (VSG) represents approximately 90% of cell surface protein and a major proportion of endoplasmic reticulum (ER) biosynthetic output. We identified four trypanosomatid-specific genes encoding candidate ER-resident proteins; all were required for normal proliferation. For Tb11.01.2640 and Tb11.01.8120, an increase in VSG abundance was found on silencing, while the protein products localized to the ER; we designated these ERAP32 and ERAP18 for ER-associated protein of 32kDa and 18kDa. Silencing ERAP32 or ERAP18 did not alter expression levels of ISG65 or ISG75, the major surface trans-membrane domain proteins. Surface biotinylation or immunoflorescence did not identify intracellular VSG accumulation, while FACS and fluorescence microscopy indicated that the cells were not increased in size, arguing for increased VSG density on the cell surface. Therefore, ERAP32 and ERAP18 are trypanosome-specific ER-localized proteins with a major role in VSG protein export and, contrary to current paradigms, VSG is not saturated on the cell surface.
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Affiliation(s)
- Ya-Nan Wang
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Ming Wang
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Mark C. Field
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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Frearson JA, Brand S, McElroy SP, Cleghorn LAT, Smid O, Stojanovski L, Price HP, Guther MLS, Torrie LS, Robinson DA, Hallyburton I, Mpamhanga CP, Brannigan JA, Wilkinson AJ, Hodgkinson M, Hui R, Qiu W, Raimi OG, van Aalten DMF, Brenk R, Gilbert IH, Read KD, Fairlamb AH, Ferguson MAJ, Smith DF, Wyatt PG. N-myristoyltransferase inhibitors as new leads to treat sleeping sickness. Nature 2010; 464:728-32. [PMID: 20360736 PMCID: PMC2917743 DOI: 10.1038/nature08893] [Citation(s) in RCA: 221] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 02/10/2010] [Indexed: 01/28/2023]
Abstract
African sleeping sickness or human African trypanosomiasis, caused by Trypanosoma brucei spp., is responsible for approximately 30,000 deaths each year. Available treatments for this disease are poor, with unacceptable efficacy and safety profiles, particularly in the late stage of the disease when the parasite has infected the central nervous system. Here we report the validation of a molecular target and the discovery of associated lead compounds with the potential to address this lack of suitable treatments. Inhibition of this target-T. brucei N-myristoyltransferase-leads to rapid killing of trypanosomes both in vitro and in vivo and cures trypanosomiasis in mice. These high-affinity inhibitors bind into the peptide substrate pocket of the enzyme and inhibit protein N-myristoylation in trypanosomes. The compounds identified have promising pharmaceutical properties and represent an opportunity to develop oral drugs to treat this devastating disease. Our studies validate T. brucei N-myristoyltransferase as a promising therapeutic target for human African trypanosomiasis.
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Affiliation(s)
- Julie A Frearson
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, University of Dundee, Dundee DD1 5EH, UK
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Price HP, Güther MLS, Ferguson MAJ, Smith DF. Myristoyl-CoA:protein N-myristoyltransferase depletion in trypanosomes causes avirulence and endocytic defects. Mol Biochem Parasitol 2009; 169:55-8. [PMID: 19782106 PMCID: PMC2789243 DOI: 10.1016/j.molbiopara.2009.09.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 09/14/2009] [Accepted: 09/17/2009] [Indexed: 12/17/2022]
Abstract
The enzyme myristoyl-CoA:protein N-myristoyltransferase (NMT) catalyses the co-translational covalent attachment of the fatty acid myristate to the N-terminus of target proteins. NMT is known to be essential for viability in Trypanosoma brucei and Leishmania major. Here we describe phenotypic analysis of T. brucei bloodstream form cells following knockdown of NMT expression by tetracycline-inducible RNA interference. Cell death occurs from 72 h post-induction, with approximately 50% of cells displaying a defect in endocytic uptake by this time. The majority of these induced cells do not have an enlarged flagellar pocket typical of a block in endocytosis but vesicle accumulation around the flagellar pocket indicates a defect in vesicular progression following endocytic fusion. Induced parasites have a wild-type or slightly enlarged Golgi apparatus, unlike the phenotype of cells with reduced expression of a major N-myristoylated protein, ARL1. Critically we show that following NMT knockdown, T. brucei bloodstream form cells are unable to establish an infection in a mouse model, therefore providing further validation of this enzyme as a target for drug development.
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Affiliation(s)
- Helen P Price
- Centre for Immunology and Infection, Department of Biology, University of York, UK.
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Anthonio EA, Brees C, Baumgart-Vogt E, Hongu T, Huybrechts SJ, Van Dijck P, Mannaerts GP, Kanaho Y, Van Veldhoven PP, Fransen M. Small G proteins in peroxisome biogenesis: the potential involvement of ADP-ribosylation factor 6. BMC Cell Biol 2009; 10:58. [PMID: 19686593 PMCID: PMC3224584 DOI: 10.1186/1471-2121-10-58] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 08/17/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Peroxisomes execute diverse and vital functions in virtually every eukaryote. New peroxisomes form by budding from pre-existing organelles or de novo by vesiculation of the ER. It has been suggested that ADP-ribosylation factors and COPI coatomer complexes are involved in these processes. RESULTS Here we show that all viable Saccharomyces cerevisiae strains deficient in one of the small GTPases which have an important role in the regulation of vesicular transport contain functional peroxisomes, and that the number of these organelles in oleate-grown cells is significantly upregulated in the arf1 and arf3 null strains compared to the wild-type strain. In addition, we provide evidence that a portion of endogenous Arf6, the mammalian orthologue of yeast Arf3, is associated with the cytoplasmic face of rat liver peroxisomes. Despite this, ablation of Arf6 did neither influence the regulation of peroxisome abundance nor affect the localization of peroxisomal proteins in cultured fetal hepatocytes. However, co-overexpression of wild-type, GTP hydrolysis-defective or (dominant-negative) GTP binding-defective forms of Arf1 and Arf6 caused mislocalization of newly-synthesized peroxisomal proteins and resulted in an alteration of peroxisome morphology. CONCLUSION These observations suggest that Arf6 is a key player in mammalian peroxisome biogenesis. In addition, they also lend strong support to and extend the concept that specific Arf isoform pairs may act in tandem to regulate exclusive trafficking pathways.
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Affiliation(s)
- Erin A Anthonio
- Department of Molecular Cell Biology, Catholic University of Leuven, Leuven, Belgium.
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Field MC, Lumb JH, Adung'a VO, Jones NG, Engstler M. Chapter 1 Macromolecular Trafficking and Immune Evasion in African Trypanosomes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 278:1-67. [DOI: 10.1016/s1937-6448(09)78001-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Koumandou VL, Natesan SKA, Sergeenko T, Field MC. The trypanosome transcriptome is remodelled during differentiation but displays limited responsiveness within life stages. BMC Genomics 2008; 9:298. [PMID: 18573209 PMCID: PMC2443814 DOI: 10.1186/1471-2164-9-298] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Accepted: 06/23/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Trypanosomatids utilise polycistronic transcription for production of the vast majority of protein-coding mRNAs, which operates in the absence of gene-specific promoters. Resolution of nascent transcripts by polyadenylation and trans-splicing, together with specific rates of mRNA turnover, serve to generate steady state transcript levels that can differ in abundance across several orders of magnitude and can be developmentally regulated. We used a targeted oligonucleotide microarray, representing the strongly developmentally-regulated T. brucei membrane trafficking system and approximately 10% of the Trypanosoma brucei genome, to investigate both between-stage, or differentiation-dependent, transcriptome changes and within-stage flexibility in response to various challenges. RESULTS 6% of the gene cohort are developmentally regulated, including several small GTPases, SNAREs, vesicle coat factors and protein kinases both consistent with and extending previous data. Therefore substantial differentiation-dependent remodeling of the trypanosome transcriptome is associated with membrane transport. Both the microarray and qRT-PCR were then used to analyse transcriptome changes resulting from specific gene over-expression, knockdown, altered culture conditions and chemical stress. Firstly, manipulation of Rab5 expression results in co-ordinate changes to clathrin protein expression levels and endocytotic activity, but no detectable changes to steady-state mRNA levels, which indicates that the effect is mediated post-transcriptionally. Secondly, knockdown of clathrin or the variant surface glycoprotein failed to perturb transcription. Thirdly, exposure to dithiothreitol or tunicamycin revealed no evidence for a classical unfolded protein response, mediated in higher eukaryotes by transcriptional changes. Finally, altered serum levels invoked little transcriptome alteration beyond changes to expression of ESAG6/7, the transferrin receptor. CONCLUSION While trypanosomes regulate mRNA abundance to effect the major changes accompanying differentiation, a given differentiated state appears transcriptionally inflexible. The implications of the absence of a transcriptome response in trypanosomes for both virulence and models of life cycle progression are discussed.
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Affiliation(s)
- V Lila Koumandou
- The Molteno Building, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
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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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How complex is GTPase signaling in trypanosomes? Trends Parasitol 2008; 24:253-7. [PMID: 18467174 DOI: 10.1016/j.pt.2008.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 01/15/2008] [Accepted: 03/06/2008] [Indexed: 11/21/2022]
Abstract
Many signaling pathways in higher eukaryotes use Ras-like small GTPases. Here, we ask how complex are these small GTPase signaling pathways in trypanosomes? We seek to address this issue by comparisons with the representation of both the GTPase molecules and their accessory factors in several genomes.
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Bowyer PW, Tate EW, Leatherbarrow RJ, Holder AA, Smith DF, Brown KA. N-myristoyltransferase: a prospective drug target for protozoan parasites. ChemMedChem 2008; 3:402-8. [PMID: 18324715 DOI: 10.1002/cmdc.200700301] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Paul W Bowyer
- Division of Cell and Molecular Biology, Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
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Sahin A, Espiau B, Tetaud E, Cuvillier A, Lartigue L, Ambit A, Robinson DR, Merlin G. The leishmania ARL-1 and Golgi traffic. PLoS One 2008; 3:e1620. [PMID: 18286177 PMCID: PMC2237903 DOI: 10.1371/journal.pone.0001620] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Accepted: 01/19/2008] [Indexed: 12/20/2022] Open
Abstract
We present here the characterisation of the Leishmania small G protein ADP-Ribosylation Factor-Like protein 1 (ARL-1). The ARL-1 gene is present in one copy per haploid genome and conserved among trypanosomatids. It encodes a protein of 20 kDa, which is equally expressed in the insect promastigote and mammalian amastigote forms of the parasite. ARL-1 localises to the Trans-Golgi Network (TGN); N-terminal myristoylation is essential for TGN localisation. In vivo expression of the LdARL-1/Q74L and LdARL-1/T51N mutants (GTP- and GDP-bound blocked forms respectively) shows that GDP/GTP cycling occurs entirely within the TGN. This is contrary to previous reports in yeast and mammals, where the mutant empty form devoid of nucleotide has been considered as the GDP-blocked form. The dominant-negative empty form mutant LdARL-1/T34N inhibits endocytosis and intracellular trafficking from the TGN to the Lysosome/Multivesicular Tubule and to the acidocalcisomes; these defects are probably related to a mislocalisation of the GRIP domain-containing vesicle tethering factors which cannot be recruited to the TGN by the cytoplasmic LdARL-1/T34N. Thus, besides the functional characterization of a new mutant and a better understanding of ARL-1 GDP/GTP cycling, this work shows that Leishmania ARL-1 is a key component of an essential pathway worth future study.
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Affiliation(s)
- Annelise Sahin
- Laboratoire de Microbiologie Cellulaire et Moléculaire et Pathogénicité, UMR CNRS 5234, Université Bordeaux 2, Bordeaux, France
| | - Benoît Espiau
- Laboratoire de Microbiologie Cellulaire et Moléculaire et Pathogénicité, UMR CNRS 5234, Université Bordeaux 2, Bordeaux, France
| | - Emmanuel Tetaud
- Laboratoire de Microbiologie Cellulaire et Moléculaire et Pathogénicité, UMR CNRS 5234, Université Bordeaux 2, Bordeaux, France
| | - Armelle Cuvillier
- Laboratoire de Microbiologie Cellulaire et Moléculaire et Pathogénicité, UMR CNRS 5234, Université Bordeaux 2, Bordeaux, France
| | - Lydia Lartigue
- Laboratoire de Microbiologie Cellulaire et Moléculaire et Pathogénicité, UMR CNRS 5234, Université Bordeaux 2, Bordeaux, France
| | - Audrey Ambit
- Laboratoire de Microbiologie Cellulaire et Moléculaire et Pathogénicité, UMR CNRS 5234, Université Bordeaux 2, Bordeaux, France
| | - Derrick R. Robinson
- Laboratoire de Microbiologie Cellulaire et Moléculaire et Pathogénicité, UMR CNRS 5234, Université Bordeaux 2, Bordeaux, France
| | - Gilles Merlin
- Laboratoire de Microbiologie Cellulaire et Moléculaire et Pathogénicité, UMR CNRS 5234, Université Bordeaux 2, Bordeaux, France
- *E-mail:
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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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Matheson LA, Hanton SL, Rossi M, Latijnhouwers M, Stefano G, Renna L, Brandizzi F. Multiple roles of ADP-ribosylation factor 1 in plant cells include spatially regulated recruitment of coatomer and elements of the Golgi matrix. PLANT PHYSIOLOGY 2007; 143:1615-27. [PMID: 17307898 PMCID: PMC1851833 DOI: 10.1104/pp.106.094953] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Recent evidence indicates that ADP-ribosylation factor 1 (ARF1) carries out multiple roles in plant cells that may be independent from the established effector complex COPI. To investigate potential COPI-independent functions, we have followed the dynamics of ARF1 and a novel putative effector, the plant golgin GRIP-related ARF-binding domain-containing Arabidopsis (Arabidopsis thaliana) protein 1 (GDAP1) in living plant cells. We present data that ascribe a new role to ARF1 in plant cell membrane traffic by showing that the GTPase functions to recruit GDAP1 to membranes. In addition, although ARF1 appears to be central to the recruitment of both COPI components and the golgin, we have established a different subcellular distribution of these ARF1 effectors. Live cell imaging demonstrates that GDAP1 and COPI are distributed on Golgi membranes. However, GDAP1 is also found on ARF1-labeled structures that lack coatomer, suggesting that the membrane environment, rather than ARF1 alone, influences the differential recruitment of ARF1 effectors. In support of this hypothesis, fluorescence recovery after photobleaching analyses demonstrated that GDAP1 and COPI have different kinetics on membranes during the cycle of activation and inactivation of ARF1. Therefore, our data support a model where modulation of the cellular functions of ARF1 in plant cells encompasses not only the intrinsic activities of the effectors, but also differential recruitment onto membranes that is spatially regulated.
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Affiliation(s)
- Loren A Matheson
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
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