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Yuan X, Kadowaki T. Protein subcellular relocalization and function of duplicated flagellar calcium binding protein genes in honey bee trypanosomatid parasite. PLoS Genet 2024; 20:e1011195. [PMID: 38437202 PMCID: PMC10939215 DOI: 10.1371/journal.pgen.1011195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 03/14/2024] [Accepted: 02/23/2024] [Indexed: 03/06/2024] Open
Abstract
The honey bee trypanosomatid parasite, Lotmaria passim, contains two genes that encode the flagellar calcium binding protein (FCaBP) through tandem duplication in its genome. FCaBPs localize in the flagellum and entire body membrane of L. passim through specific N-terminal sorting sequences. This finding suggests that this is an example of protein subcellular relocalization resulting from gene duplication, altering the intracellular localization of FCaBP. However, this phenomenon may not have occurred in Leishmania, as one or both of the duplicated genes have become pseudogenes. Multiple copies of the FCaBP gene are present in several Trypanosoma species and Leptomonas pyrrhocoris, indicating rapid evolution of this gene in trypanosomatid parasites. The N-terminal flagellar sorting sequence of L. passim FCaBP1 is in close proximity to the BBSome complex, while that of Trypanosoma brucei FCaBP does not direct GFP to the flagellum in L. passim. Deletion of the two FCaBP genes in L. passim affected growth and impaired flagellar morphogenesis and motility, but it did not impact host infection. Therefore, FCaBP represents a duplicated gene with a rapid evolutionary history that is essential for flagellar structure and function in a trypanosomatid parasite.
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Affiliation(s)
- Xuye Yuan
- Department of Biological Sciences, School of Science, Xi'an Jiaotong-Liverpool University, Suzhou Dushu Lake Higher Education Town, Jiangsu Province, China
| | - Tatsuhiko Kadowaki
- Department of Biological Sciences, School of Science, Xi'an Jiaotong-Liverpool University, Suzhou Dushu Lake Higher Education Town, Jiangsu Province, China
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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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3
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Rodríguez-Durán J, Gallardo JP, Alba Soto CD, Gómez KA, Potenza M. The Kinetoplastid-Specific Protein TcCAL1 Plays Different Roles During In Vitro Differentiation and Host-Cell Invasion in Trypanosoma cruzi. Front Cell Infect Microbiol 2022; 12:901880. [PMID: 35846750 PMCID: PMC9280158 DOI: 10.3389/fcimb.2022.901880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Abstract
In the pathogen Typanosoma cruzi, the calcium ion (Ca2+) regulates key processes for parasite survival. However, the mechanisms decoding Ca2+ signals are not fully identified or understood. Here, we investigate the role of a hypothetical Ca2+-binding protein named TcCAL1 in the in vitro life cycle of T. cruzi. Results showed that the overexpression of TcCAL1 fused to a 6X histidine tag (TcCAL1-6xHis) impaired the differentiation of epimastigotes into metacyclic trypomastigotes, significantly decreasing metacyclogenesis rates. When the virulence of transgenic metacyclic trypomastigotes was explored in mammalian cell invasion assays, we found that the percentage of infection was significantly higher in Vero cells incubated with TcCAL1-6xHis-overexpressing parasites than in controls, as well as the number of intracellular amastigotes. Additionally, the percentage of Vero cells with adhered metacyclic trypomastigotes significantly increased in samples incubated with TcCAL1-6xHis-overexpressing parasites compared with controls. In contrast, the differentiation rates from metacyclic trypomastigotes to axenic amastigotes or the epimastigote proliferation in the exponential phase of growth have not been affected by TcCAL1-6xHis overexpression. Based on our findings, we speculate that TcCAL1 exerts its function by sequestering intracellular Ca2+ by its EF-hand motifs (impairing metacyclogenesis) and/or due to an unknown activity which could be amplified by the ion binding (promoting cell invasion). This work underpins the importance of studying the kinetoplastid-specific proteins with unknown functions in pathogen parasites.
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Affiliation(s)
- Jessica Rodríguez-Durán
- Laboratorio de Biología e Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor Torres”—CONICET, Buenos Aires, Argentina
| | - Juan Pablo Gallardo
- Laboratorio de Biología e Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor Torres”—CONICET, Buenos Aires, Argentina
| | - Catalina Dirney Alba Soto
- Instituto de Microbiología y Parasitología Médica, Departamento de Microbiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Karina Andrea Gómez
- Laboratorio de Biología e Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor Torres”—CONICET, Buenos Aires, Argentina
| | - Mariana Potenza
- Laboratorio de Biología e Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor Torres”—CONICET, Buenos Aires, Argentina
- *Correspondence: Mariana Potenza, ;
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Versteeg L, Adhikari R, Poveda C, Villar-Mondragon MJ, Jones KM, Hotez PJ, Bottazzi ME, Tijhaar E, Pollet J. Location and expression kinetics of Tc24 in different life stages of Trypanosoma cruzi. PLoS Negl Trop Dis 2021; 15:e0009689. [PMID: 34478444 PMCID: PMC8415617 DOI: 10.1371/journal.pntd.0009689] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 07/27/2021] [Indexed: 12/03/2022] Open
Abstract
Tc24-C4, a modified recombinant flagellar calcium-binding protein of Trypanosoma cruzi, is under development as a therapeutic subunit vaccine candidate to prevent or delay progression of chronic Chagasic cardiomyopathy. When combined with Toll-like receptor agonists, Tc24-C4 immunization reduces parasitemia, parasites in cardiac tissue, and cardiac fibrosis and inflammation in animal models. To support further research on the vaccine candidate and its mechanism of action, murine monoclonal antibodies (mAbs) against Tc24-C4 were generated. Here, we report new findings made with mAb Tc24-C4/884 that detects Tc24-WT and Tc24-C4, as well as native Tc24 in T. cruzi on ELISA, western blots, and different imaging techniques. Surprisingly, detection of Tc24 by Tc24-C/884 in fixed T. cruzi trypomastigotes required permeabilization of the parasite, revealing that Tc24 is not exposed on the surface of T. cruzi, making a direct role of antibodies in the induced protection after Tc24-C4 immunization less likely. We further observed that after immunostaining T. cruzi-infected cells with mAb Tc24-C4/884, the expression of Tc24 decreases significantly when T. cruzi trypomastigotes enter host cells and transform into amastigotes. However, Tc24 is then upregulated in association with parasite flagellar growth linked to re-transformation into the trypomastigote form, prior to host cellular escape. These observations are discussed in the context of potential mechanisms of vaccine immunity.
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Affiliation(s)
- Leroy Versteeg
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
- Cell Biology and Immunology Group, Wageningen University, Wageningen, The Netherlands
| | - Rakesh Adhikari
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
| | - Cristina Poveda
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
| | - Maria Jose Villar-Mondragon
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kathryn M. Jones
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
| | - Peter J. Hotez
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Maria Elena Bottazzi
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Edwin Tijhaar
- Cell Biology and Immunology Group, Wageningen University, Wageningen, The Netherlands
| | - Jeroen Pollet
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
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Arnal A, Villanueva‐Lizama L, Teh‐Poot C, Herrera C, Dumonteil E. Extent of polymorphism and selection pressure on the Trypanosoma cruzi vaccine candidate antigen Tc24. Evol Appl 2020; 13:2663-2672. [PMID: 33294015 PMCID: PMC7691455 DOI: 10.1111/eva.13068] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/30/2020] [Accepted: 07/12/2020] [Indexed: 01/10/2023] Open
Abstract
INTRODUCTION Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is a major public health problem in the Americas, and existing drugs have severe limitations. In this context, a vaccine would be an attractive alternative for disease control. One of the difficulties in developing an effective vaccine lies in the high genetic diversity of T. cruzi. In this study, we evaluated the level of sequence diversity of the leading vaccine candidate Tc24 in multiple parasite strains. METHODS AND RESULTS We quantified its level of polymorphism within and between T. cruzi discrete typing units (DTUs) and how this potential polymorphism is structured by different selective pressures. We observed a low level of polymorphism of Tc24 protein, weakly associated with parasite DTUs, but not with the geographic origin of the strains. In particular, Tc24 was under strong purifying selection pressure and predicted CD8+ T-cell epitopes were mostly conserved. Tc24 strong conservation may be associated with structural/functional constrains to preserve EF hand domains and their calcium-binding loops, and Tc24 is likely important for the parasite fitness. DISCUSSION Together, these results show that a vaccine based on Tc24 is likely to be effective against a wide diversity of parasite strains across the American continent, and further development of this vaccine candidate should be a high priority.
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Affiliation(s)
- Audrey Arnal
- Laboratorio de ParasitologíaCentro de Investigaciones Regionales “DrHideyo Noguchi”Universidad Autónoma de YucatánMéridaMexico
- Departamento de Ecología de la BiodiversidadInstituto de EcologíaUniversidad Nacional Autónoma de MéxicoCiudad de MéxicoMéxico
| | - Liliana Villanueva‐Lizama
- Laboratorio de ParasitologíaCentro de Investigaciones Regionales “DrHideyo Noguchi”Universidad Autónoma de YucatánMéridaMexico
| | - Christian Teh‐Poot
- Laboratorio de ParasitologíaCentro de Investigaciones Regionales “DrHideyo Noguchi”Universidad Autónoma de YucatánMéridaMexico
| | - Claudia Herrera
- Department of Tropical MedicineSchool of Public Health and Tropical MedicineTulane UniversityNew OrleansLAUSA
- Vector‐Borne and Infectious Disease Research CenterTulane UniversityNew OrleansLAUSA
| | - Eric Dumonteil
- Department of Tropical MedicineSchool of Public Health and Tropical MedicineTulane UniversityNew OrleansLAUSA
- Vector‐Borne and Infectious Disease Research CenterTulane UniversityNew OrleansLAUSA
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Ramakrishnan S, Docampo R. Membrane Proteins in Trypanosomatids Involved in Ca 2+ Homeostasis and Signaling. Genes (Basel) 2018; 9:E304. [PMID: 29921754 PMCID: PMC6027440 DOI: 10.3390/genes9060304] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/11/2018] [Accepted: 06/14/2018] [Indexed: 01/10/2023] Open
Abstract
Calcium ion (Ca2+) serves as a second messenger for a variety of cell functions in trypanosomes. Several proteins in the plasma membrane, acidocalcisomes, endoplasmic reticulum, and mitochondria are involved in its homeostasis and in cell signaling roles. The plasma membrane has a Ca2+ channel for its uptake and a plasma membrane-type Ca2+-ATPase (PMCA) for its efflux. A similar PMCA is also located in acidocalcisomes, acidic organelles that are the primary Ca2+ store and that possess an inositol 1,4,5-trisphosphate receptor (IP₃R) for Ca2+ efflux. Their mitochondria possess a mitochondrial calcium uniporter complex (MCUC) for Ca2+ uptake and a Ca2+/H⁺ exchanger for Ca2+ release. The endoplasmic reticulum has a sarcoplasmic-endoplasmic reticulum-type Ca2+-ATPase (SERCA) for Ca2+ uptake but no Ca2+ release mechanism has been identified. Additionally, the trypanosomatid genomes contain other membrane proteins that could potentially bind calcium and await further characterization.
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Affiliation(s)
- Srinivasan Ramakrishnan
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
| | - Roberto Docampo
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
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Brown RWB, Sharma AI, Engman DM. Dynamic protein S-palmitoylation mediates parasite life cycle progression and diverse mechanisms of virulence. Crit Rev Biochem Mol Biol 2017; 52:145-162. [PMID: 28228066 PMCID: PMC5560270 DOI: 10.1080/10409238.2017.1287161] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Eukaryotic parasites possess complex life cycles and utilize an assortment of molecular mechanisms to overcome physical barriers, suppress and/or bypass the host immune response, including invading host cells where they can replicate in a protected intracellular niche. Protein S-palmitoylation is a dynamic post-translational modification in which the fatty acid palmitate is covalently linked to cysteine residues on proteins by the enzyme palmitoyl acyltransferase (PAT) and can be removed by lysosomal palmitoyl-protein thioesterase (PPT) or cytosolic acyl-protein thioesterase (APT). In addition to anchoring proteins to intracellular membranes, functions of dynamic palmitoylation include - targeting proteins to specific intracellular compartments via trafficking pathways, regulating the cycling of proteins between membranes, modulating protein function and regulating protein stability. Recent studies in the eukaryotic parasites - Plasmodium falciparum, Toxoplasma gondii, Trypanosoma brucei, Cryptococcus neoformans and Giardia lamblia - have identified large families of PATs and palmitoylated proteins. Many palmitoylated proteins are important for diverse aspects of pathogenesis, including differentiation into infective life cycle stages, biogenesis and tethering of secretory organelles, assembling the machinery powering motility and targeting virulence factors to the plasma membrane. This review aims to summarize our current knowledge of palmitoylation in eukaryotic parasites, highlighting five exemplary mechanisms of parasite virulence dependent on palmitoylation.
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Affiliation(s)
- Robert W B Brown
- a Department of Pathology and Laboratory Medicine , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - Aabha I Sharma
- b Departments of Pathology and Microbiology-Immunology , Northwestern University , Chicago , IL , USA
| | - David M Engman
- a Department of Pathology and Laboratory Medicine , Cedars-Sinai Medical Center , Los Angeles , CA , USA
- b Departments of Pathology and Microbiology-Immunology , Northwestern University , Chicago , IL , USA
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Seid CA, Jones KM, Pollet J, Keegan B, Hudspeth E, Hammond M, Wei J, McAtee CP, Versteeg L, Gutierrez A, Liu Z, Zhan B, Respress JL, Strych U, Bottazzi ME, Hotez PJ. Cysteine mutagenesis improves the production without abrogating antigenicity of a recombinant protein vaccine candidate for human chagas disease. Hum Vaccin Immunother 2016; 13:621-633. [PMID: 27737611 DOI: 10.1080/21645515.2016.1242540] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
A therapeutic vaccine for human Chagas disease is under development by the Sabin Vaccine Institute Product Development Partnership. The aim of the vaccine is to significantly reduce the parasite burden of Trypanosoma cruzi in humans, either as a standalone product or in combination with conventional chemotherapy. Vaccination of mice with Tc24 formulated with monophosphoryl-lipid A (MPLA) adjuvant results in a Th1 skewed immune response with elevated IgG2a and IFNγ levels and a statistically significant decrease in parasitemia following T. cruzi challenge. Tc24 was therefore selected for scale-up and further evaluation. During scale up and downstream process development, significant protein aggregation was observed due to intermolecular disulfide bond formation. To prevent protein aggregation, cysteine codons were replaced with serine codons which resulted in the production of a non-aggregated and soluble recombinant protein, Tc24-C4. No changes to the secondary structure of the modified molecule were detected by circular dichroism. Immunization of mice with wild-type Tc24 or Tc24-C4, formulated with E6020 (TLR4 agonist analog to MPLA) emulsified in a squalene-oil-in-water emulsion, resulted in IgG2a and antigen specific IFNγ production levels from splenocytes that were not significantly different, indicating that eliminating putative intermolecular disulfide bonds had no significant impact on the immunogenicity of the molecule. In addition, vaccination with either formulated wild type Tc24 or Tc24-C4 antigen also significantly increased survival and reduced cardiac parasite burden in mice. Investigations are now underway to examine the efficacy of Tc24-C4 formulated with other adjuvants to reduce parasite burden and increase survival in pre-clinical studies.
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Affiliation(s)
- Christopher A Seid
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Kathryn M Jones
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA
| | - Jeroen Pollet
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA
| | - Brian Keegan
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Elissa Hudspeth
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Molly Hammond
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Junfei Wei
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - C Patrick McAtee
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Leroy Versteeg
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Amanda Gutierrez
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Zhuyun Liu
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA
| | - Bin Zhan
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA
| | - Jonathan L Respress
- d Southwest Electronic Energy Medical Research Institute (SWEMRI) , Missouri City , TX , USA
| | - Ulrich Strych
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA
| | - Maria Elena Bottazzi
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA
| | - Peter J Hotez
- a Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development , Houston , TX , USA.,b Departments of Pediatrics and Molecular Virology and Microbiology , National School of Tropical Medicine, Baylor College of Medicine , Houston , TX , USA.,c James A. Baker III Institute for Public Policy , Rice University , Houston , TX , USA
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Sanchez MA, Tran KD, Valli J, Hobbs S, Johnson E, Gluenz E, Landfear SM. KHARON Is an Essential Cytoskeletal Protein Involved in the Trafficking of Flagellar Membrane Proteins and Cell Division in African Trypanosomes. J Biol Chem 2016; 291:19760-73. [PMID: 27489106 DOI: 10.1074/jbc.m116.739235] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Indexed: 11/06/2022] Open
Abstract
African trypanosomes and related kinetoplastid parasites selectively traffic specific membrane proteins to the flagellar membrane, but the mechanisms for this trafficking are poorly understood. We show here that KHARON, a protein originally identified in Leishmania parasites, interacts with a putative trypanosome calcium channel and is required for its targeting to the flagellar membrane. KHARON is located at the base of the flagellar axoneme, where it likely mediates targeting of flagellar membrane proteins, but is also on the subpellicular microtubules and the mitotic spindle. Hence, KHARON is probably a multifunctional protein that associates with several components of the trypanosome cytoskeleton. RNA interference-mediated knockdown of KHARON mRNA results in failure of the calcium channel to enter the flagellar membrane, detachment of the flagellum from the cell body, and disruption of mitotic spindles. Furthermore, knockdown of KHARON mRNA induces a lethal failure of cytokinesis in both bloodstream (mammalian host) and procyclic (insect vector) life cycle stages, and KHARON is thus critical for parasite viability.
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Affiliation(s)
- Marco A Sanchez
- From the Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239 and
| | - Khoa D Tran
- From the Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239 and
| | - Jessica Valli
- the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Sam Hobbs
- From the Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239 and
| | - Errin Johnson
- the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Eva Gluenz
- the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Scott M Landfear
- From the Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239 and
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10
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Eyford BA, Kaufman L, Salama-Alber O, Loveless B, Pope ME, Burke RD, Matovu E, Boulanger MJ, Pearson TW. Characterization of Calflagin, a Flagellar Calcium-Binding Protein from Trypanosoma congolense. PLoS Negl Trop Dis 2016; 10:e0004510. [PMID: 27055052 PMCID: PMC4824491 DOI: 10.1371/journal.pntd.0004510] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 02/12/2016] [Indexed: 11/23/2022] Open
Abstract
Background Identification of species-specific trypanosome molecules is important for laboratory- and field-based research into epidemiology and disease diagnosis. Although Trypanosoma congolense is the most important trypanosome pathogen of cattle in Africa, no species-specific molecules found in infective bloodstream forms (BSF) of the parasites have been identified, thus limiting development of diagnostic tests. Methods Immuno-mass spectrometric methods were used to identify a protein that is recognized by a T. congolense-specific monoclonal antibody (mAb) Tc6/42.6.4. The identified molecule was expressed as a recombinant protein in E. coli and was tested in several immunoassays for its ability to interact with the mAb. The three dimensional structure of the protein was modeled and compared to crystal- and NMR-structures of the homologous proteins from T. cruzi and T. brucei respectively, in order to examine structural differences leading to the different immunoreactivity of the T. congolense molecule. Enzyme-linked immunosorbent assays (ELISA) were used to measure antibodies produced by trypanosome-infected African cattle in order to assess the potential for use of T. congolense calflagin in a serodiagnostic assay. Results The antigen recognized by the T. congolense-specific mAb Tc6/42.6.4 was identified as a flagellar calcium-binding protein, calflagin. The recombinant molecule showed immunoreactivity with the T. congolense-specific mAb confirming that it is the cognate antigen. Immunofluorescence experiments revealed that Ca2+ modulated the localization of the calflagin molecule in trypanosomes. Structural modelling and comparison with calflagin homologues from other trypanosomatids revealed four non-conserved regions on the surface of the T. congolense molecule that due to differences in surface chemistry and structural topography may form species-specific epitopes. ELISAs using the recombinant calflagin as antigen to detect antibodies in trypanosome-infected cattle showed that the majority of cattle had antibody responses. Area under the Receiver-Operating Characteristic (ROC) curves, associated with host IgG and IgM, were calculated to be 0.623 and 0.709 respectively, indicating a positive correlation between trypanosome infection and the presence of anti-calflagin antibodies. Conclusions While calflagin is conserved among different species of African trypanosomes, our results show that T. congolense calflagin possesses unique epitopes that differentiate this protein from homologues in other trypanosome species. MAb Tc6/42.6.4 has clear utility as a laboratory tool for identifying T. congolense. T. congolense calflagin has potential as a serodiagnostic antigen and should be explored further for its utility in antigen-detection assays for diagnosis of cattle infections. African trypanosomes are parasites that infect humans and domestic animals, causing severe socioeconomic distress in sub-Saharan Africa. Thus developing tools for laboratory- and field-based research for application to epidemiology and disease diagnosis is important if the diseases caused by these parasites are to be controlled. Although Trypanosoma congolense is the most important trypanosome pathogen of cattle in Africa, no species-specific molecules found in infective bloodstream forms (BSF) of the parasites have been identified, thus limiting development of diagnostic tests and epidemiological tools. We have biochemically characterized and modeled the structure of one such molecule, called calflagin, from this parasite and genetically engineered and purified a form of the protein for use in testing cattle for trypanosome infections. In addition, we made new monoclonal antibodies to the calflagin molecule. Our results show that the calflagin and its specific antibodies are useful tools for research in epidemiological and diagnostic applications.
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Affiliation(s)
- Brett A. Eyford
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Laura Kaufman
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Orly Salama-Alber
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Bianca Loveless
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Matthew E. Pope
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Robert D. Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Enock Matovu
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Martin J. Boulanger
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Terry W. Pearson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
- * E-mail:
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Herrera LJ, Brand S, Santos A, Nohara LL, Harrison J, Norcross NR, Thompson S, Smith V, Lema C, Varela-Ramirez A, Gilbert IH, Almeida IC, Maldonado RA. Validation of N-myristoyltransferase as Potential Chemotherapeutic Target in Mammal-Dwelling Stages of Trypanosoma cruzi. PLoS Negl Trop Dis 2016; 10:e0004540. [PMID: 27128971 PMCID: PMC4851402 DOI: 10.1371/journal.pntd.0004540] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 02/22/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Trypanosoma cruzi causes Chagas disease, an endemic and debilitating illness in Latin America. Lately, owing to extensive population movements, this neglected tropical disease has become a global health concern. The two clinically available drugs for the chemotherapy of Chagas disease have rather high toxicity and limited efficacy in the chronic phase of the disease, and may induce parasite resistance. The development of new anti-T. cruzi agents is therefore imperative. The enzyme N-myristoyltransferase (NMT) has recently been biochemically characterized, shown to be essential in Leishmania major, Trypanosoma brucei, and T. cruzi¸ and proposed as promising chemotherapeutic target in these trypanosomatids. METHODOLOGY/PRINCIPAL FINDINGS Here, using high-content imaging we assayed eight known trypanosomatid NMT inhibitors, against mammal-dwelling intracellular amastigote and trypomastigote stages and demonstrated that three of them (compounds 1, 5, and 8) have potent anti-proliferative effect at submicromolar concentrations against T. cruzi, with very low toxicity against human epithelial cells. Moreover, metabolic labeling using myristic acid, azide showed a considerable decrease in the myristoylation of proteins in parasites treated with NMT inhibitors, providing evidence of the on-target activity of the inhibitors. CONCLUSIONS/SIGNIFICANCE Taken together, our data point out to the potential use of NMT inhibitors as anti-T. cruzi chemotherapy.
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Affiliation(s)
- Linda J. Herrera
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Stephen Brand
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Andres Santos
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Lilian L. Nohara
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Justin Harrison
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Neil R. Norcross
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Stephen Thompson
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Victoria Smith
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Carolina Lema
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Armando Varela-Ramirez
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Ian H. Gilbert
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, United Kingdom
| | - Igor C. Almeida
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Rosa A. Maldonado
- The Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
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12
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Landfear SM, Tran KD, Sanchez MA. Flagellar membrane proteins in kinetoplastid parasites. IUBMB Life 2015; 67:668-76. [PMID: 26599841 DOI: 10.1002/iub.1411] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 08/06/2015] [Indexed: 11/06/2022]
Abstract
All kinetoplastid parasites, including protozoa such as Leishmania species, Trypanosoma brucei, and Trypanosoma cruzi that cause devastating diseases in humans and animals, are flagellated throughout their life cycles. Although flagella were originally thought of primarily as motility organelles, flagellar functions in other critical processes, especially in sensing and signal transduction, have become more fully appreciated in the recent past. The flagellar membrane is a highly specialized subdomain of the surface membrane, and flagellar membrane proteins are likely to be critical components for all the biologically important roles of flagella. In this review, we summarize recent discoveries relevant to flagellar membrane proteins in these parasites, including the identification of such proteins, investigation of their biological functions, and mechanisms of selective trafficking to the flagellar membrane. Prospects for future investigations and current unsolved problems are highlighted.
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Affiliation(s)
- Scott M Landfear
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR, USA
| | - Khoa D Tran
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR, USA
| | - Marco A Sanchez
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR, USA
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13
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Ooi CP, Rotureau B, Gribaldo S, Georgikou C, Julkowska D, Blisnick T, Perrot S, Subota I, Bastin P. The Flagellar Arginine Kinase in Trypanosoma brucei Is Important for Infection in Tsetse Flies. PLoS One 2015. [PMID: 26218532 PMCID: PMC4517888 DOI: 10.1371/journal.pone.0133676] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
African trypanosomes are flagellated parasites that cause sleeping sickness. Parasites are transmitted from one mammalian host to another by the bite of a tsetse fly. Trypanosoma brucei possesses three different genes for arginine kinase (AK) including one (AK3) that encodes a protein localised to the flagellum. AK3 is characterised by the presence of a unique amino-terminal insertion that specifies flagellar targeting. We show here a phylogenetic analysis revealing that flagellar AK arose in two independent duplication events in T. brucei and T. congolense, the two species of African trypanosomes that infect the tsetse midgut. In T. brucei, AK3 is detected in all stages of parasite development in the fly (in the midgut and in the salivary glands) as well as in bloodstream cells, but with predominance at insect stages. Genetic knockout leads to a slight reduction in motility and impairs parasite infectivity towards tsetse flies in single and competition experiments, both phenotypes being reverted upon expression of an epitope-tagged version of AK3. We speculate that this flagellar arginine kinase is important for T. brucei infection of tsetse, especially in the context of mixed infections and that its flagellar targeting relies on a system equivalent to that discovered for calflagins, a family of trypanosome flagellum calcium binding proteins.
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Affiliation(s)
- Cher-Pheng Ooi
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015, Paris, France
| | - Brice Rotureau
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015, Paris, France
| | - Simonetta Gribaldo
- Molecular Biology of Gene in Extremophiles Unit, Department of Microbiology, Institut Pasteur, 25 rue du Docteur Roux, 75015, Paris, France
| | - Christina Georgikou
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015, Paris, France
| | - Daria Julkowska
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015, Paris, France
| | - Thierry Blisnick
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015, Paris, France
| | - Sylvie Perrot
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015, Paris, France
| | - Ines Subota
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015, Paris, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015, Paris, France
- * E-mail:
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14
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Maric D, Olson CL, Xu X, Ames JB, Engman DM. Calcium-dependent membrane association of a flagellar calcium sensor does not require calcium binding. Mol Biochem Parasitol 2015; 201:72-75. [PMID: 26099941 DOI: 10.1016/j.molbiopara.2015.06.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/07/2015] [Accepted: 06/11/2015] [Indexed: 01/20/2023]
Abstract
Flagellar calcium-binding protein (FCaBP) is a dually acylated Ca(2+) sensor in the Trypanosoma cruzi flagellar membrane that undergoes a massive conformational change upon Ca(2+) binding. It is similar to neuronal Ca(2+) sensors, like recoverin, which regulate their binding partners through a calcium acyl switch mechanism. FCaBP is washed out of permeabilized cells with buffers containing EDTA, indicating Ca(2+)-dependent flagellar membrane association. We hypothesized that, like recoverin, FCaBP projects its acyl groups in the presence of Ca(2+), permitting flagellar membrane and binding partner association and that it sequesters the acyl groups in low Ca(2+), disassociating from the membrane and releasing its binding partner to perform a presumed enzymatic function. The X-ray crystal structure of FCaBP suggests that the acyl groups are always exposed, so we set out to test our hypothesis directly. We generated T. cruzi transfectants expressing FCaBP or Ca(2+)-binding mutant FCaBP(E151Q/E188Q) and recombinant wildtype and mutant proteins as well. Both FCaBP and FCaBP(E151Q/E188Q) were found to associate with lipid rafts, indicating the Ca(2+)-independence of this association. To our initial surprise, FCaBP(E151Q/E188Q), like wildtype FCaBP, exhibited Ca(2+)-dependent flagellar membrane association, even though this protein does not bind Ca(2+) itself [16]. One possible explanation for this is that FCaBP(E151Q/E188Q), like some other Ca(2+) sensors, may form dimers and that dimerization of FCaBP(E151Q/E188Q) with endogenous wildtype FCaBP might explain its Ca(2+)-dependent localization. Indeed both proteins are able to form dimers in the presence and absence of Ca(2+). These results suggest that FCaBP possesses two distinct Ca(2+)-dependent interactions-one involving a Ca(2+)-induced change in conformation and another perhaps involving binding partner association.
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Affiliation(s)
- Danijela Maric
- Departments of Pathology and Microbiology-Immunology, Northwestern University, Chicago, IL 60611, United States
| | - Cheryl L Olson
- Departments of Pathology and Microbiology-Immunology, Northwestern University, Chicago, IL 60611, United States
| | - Xianzhong Xu
- Department of Chemistry, University of California, Davis, CA 95616, United States
| | - James B Ames
- Department of Chemistry, University of California, Davis, CA 95616, United States
| | - David M Engman
- Departments of Pathology and Microbiology-Immunology, Northwestern University, Chicago, IL 60611, United States.
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15
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Guanylate Cyclase-Activating Protein-2 Undergoes Structural Changes upon Binding to Detergent Micelles and Bicelles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2767-77. [DOI: 10.1016/j.bbamem.2014.07.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 07/11/2014] [Accepted: 07/14/2014] [Indexed: 11/23/2022]
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16
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Xu X, Olson CL, Engman DM, Ames JB. (1)H, (15)N, and (13)C chemical shift assignments of the calflagin Tb24 flagellar calcium binding protein of Trypanosoma brucei. BIOMOLECULAR NMR ASSIGNMENTS 2013; 7:9-12. [PMID: 22382573 PMCID: PMC6467503 DOI: 10.1007/s12104-012-9366-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 02/20/2012] [Indexed: 05/31/2023]
Abstract
Flagellar calcium binding proteins are expressed in a variety of trypanosomes and are potential drug targets for Chagas disease and African sleeping sickness. We report complete NMR chemical shift assignments of the flagellar calcium binding protein calflagin Tb24 of Trypanosoma brucei. (BMRB no. 18011).
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Affiliation(s)
- Xianzhong Xu
- Department of Chemistry, University of California, Davis, CA 95616
| | - Cheryl L. Olson
- Departments of Pathology and Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - David M. Engman
- Departments of Pathology and Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - James B. Ames
- Department of Chemistry, University of California, Davis, CA 95616
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17
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Xu X, Olson CL, Engman DM, Ames JB. NMR structure of the calflagin Tb24 flagellar calcium binding protein of Trypanosoma brucei. Protein Sci 2012; 21:1942-7. [PMID: 23011904 DOI: 10.1002/pro.2167] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 09/14/2012] [Accepted: 09/17/2012] [Indexed: 01/13/2023]
Abstract
Flagellar calcium binding proteins are expressed in a variety of trypanosomes and are potential drug targets for Chagas disease and African sleeping sickness. The flagellar calcium binding protein calflagin of Trypanosoma brucei (called Tb24) is a myristoylated and palmitoylated EF-hand protein that is targeted to the inner leaflet of the flagellar membrane. The Tb24 protein may also interact with proteins on the membrane surface that may be different from those bound to flagellar calcium binding proteins (FCaBPs) in T. cruzi. We report here the NMR structure of Tb24 that contains four EF-hand motifs bundled in a compact arrangement, similar to the overall fold of T. cruzi FCaBP (RMSD = 1.0 Å). A cluster of basic residues (K22, K25, K31, R36, and R38) located on a surface near the N-terminal myristoyl group may be important for membrane binding. Non-conserved residues on the surface of a hydrophobic groove formed by EF2 (P91, Q95, D103, and V108) and EF4 (C194, T198, K199, Q202, and V203) may serve as a target protein binding site and could have implications for membrane target recognition.
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Affiliation(s)
- Xianzhong Xu
- Department of Chemistry, University of California, Davis, California 95616, USA
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18
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Maclean LM, O'Toole PJ, Stark M, Marrison J, Seelenmeyer C, Nickel W, Smith DF. Trafficking and release of Leishmania metacyclic HASPB on macrophage invasion. Cell Microbiol 2012; 14:740-61. [PMID: 22256896 PMCID: PMC3491706 DOI: 10.1111/j.1462-5822.2012.01756.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Proteins of the Leishmania hydrophilic acylated surface protein B (HASPB) family are only expressed in infective parasites (both extra- and intracellular stages) and, together with the peripheral membrane protein SHERP (small hydrophilic endoplasmic reticulum-associated protein), are essential for parasite differentiation (metacyclogenesis) in the sand fly vector. HASPB is a ‘non-classically’ secreted protein, requiring N-terminal acylation for trafficking to and exposure on the plasma membrane. Here, we use live cell imaging methods to further explore this pathway to the membrane and flagellum. Unlike HASPB trafficking in transfected mammalian cells, we find no evidence for a phosphorylation-regulated recycling pathway in metacyclic parasites. Once at the plasma membrane, HASPB18–GFP (green fluorescent protein) can undergo bidirectional movement within the inner leaflet of the membrane and on the flagellum. Transfer of fluorescent protein between the flagellum and the plasma membrane is compromised, however, suggesting the presence of a diffusion barrier at the base of the Leishmania flagellum. Full-length HASPB is released from the metacyclic parasite surface on to macrophages during phagocytosis but while expression is maintained in intracellular amastigotes, HASPB cannot be detected on the external surface in these cells. Thus HASPB may be a dual function protein that is shed by the infective metacyclic but retained internally once Leishmania are taken up by macrophages.
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Affiliation(s)
- Lorna M Maclean
- Centre for Immunology and Infection, Department of Biology/Hull York Medical School, University of York, York YO10 5DD, UK
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19
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Maric D, McGwire BS, Buchanan KT, Olson CL, Emmer BT, Epting CL, Engman DM. Molecular determinants of ciliary membrane localization of Trypanosoma cruzi flagellar calcium-binding protein. J Biol Chem 2011; 286:33109-17. [PMID: 21784841 DOI: 10.1074/jbc.m111.240895] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The flagellar calcium-binding protein (FCaBP) of Trypanosoma cruzi is localized to the flagellar membrane in all life cycle stages of the parasite. Myristoylation and palmitoylation of the N terminus of FCaBP are necessary for flagellar membrane targeting. Not all dually acylated proteins in T. cruzi are flagellar, however. Other determinants of FCaBP therefore likely contribute to flagellar specificity. We generated T. cruzi transfectants expressing the N-terminal 24 or 12 amino acids of FCaBP fused to GFP. Analysis of these mutants revealed that although amino acids 1-12 are sufficient for dual acylation and membrane binding, amino acids 13-24 are required for flagellar specificity and lipid raft association. Mutagenesis of several conserved lysine residues in the latter peptide demonstrated that these residues are essential for flagellar targeting and lipid raft association. Finally, FCaBP was expressed in the protozoan Leishmania amazonensis, which lacks FCaBP. The flagellar localization and membrane association of FCaBP in L. amazonensis suggest that the mechanisms for flagellar targeting, including a specific palmitoyl acyltransferase, are conserved in this organism.
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Affiliation(s)
- Danijela Maric
- Department of Pathology, Northwestern University, Chicago, Illinois 60611, USA
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Expresión diferencial entre estadios de Trypanosoma cruzi I en el aislamiento de un paciente con cardiomiopatía chagásica crónica de zona endémica de Santander, Colombia. BIOMEDICA 2011. [DOI: 10.7705/biomedica.v31i4.400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Composition and sensory function of the trypanosome flagellar membrane. Curr Opin Microbiol 2010; 13:466-72. [PMID: 20580599 DOI: 10.1016/j.mib.2010.06.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 06/02/2010] [Accepted: 06/02/2010] [Indexed: 12/15/2022]
Abstract
A cilium is an extension of the cell that contains an axonemal complex of microtubules and associated proteins bounded by a membrane which is contiguous with the cell body membrane. Cilia may be nonmotile or motile, the latter having additional specific roles in cell or fluid movement. The term flagellum refers to the motile cilium of free-living single cells (e.g. bacteria, archaea, spermatozoa, and protozoa). In eukaryotes, both nonmotile and motile cilia possess sensory functions. The ciliary interior (cilioplasm) is separated from the cytoplasm by a selective barrier that prevents passive diffusion of molecules between the two domains. The sensory functions of cilia reside largely in the membrane and signals generated in the cilium are transduced into a variety of cellular responses. In this review we discuss the structure and biogenesis of the cilium, with special attention to the trypanosome flagellar membrane, its lipid and protein composition and its proposed roles in sensing and signaling.
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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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Tull D, Naderer T, Spurck T, Mertens HDT, Heng J, McFadden GI, Gooley PR, McConville MJ. Membrane protein SMP-1 is required for normal flagellum function in Leishmania. J Cell Sci 2010; 123:544-54. [PMID: 20086045 DOI: 10.1242/jcs.059097] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Eukaryotic flagella and cilia are surrounded by a membrane that is continuous with, but distinct from, the rest of the plasma membrane. In Leishmania parasites, the inner leaflet of the flagellar membrane is coated with the acylated membrane protein, SMP-1. Here, we provide evidence that SMP-1 stabilizes the flagellar membrane and is required for flagella elongation and function. The expression and flagella targeting of SMP-1 is tightly associated with flagella elongation during amastigote to promastigote differentiation. Deletion of the genes encoding SMP-1 and the flagellar pocket protein SMP-2, led to the production of short flagella and defects in motility. Alterations in the physical properties of the smp-1/smp-2(-/-) flagellar membrane were suggested by: (1) the accumulation of membrane vesicles in the flagellar matrix, and (2) further retraction of flagella following partial inhibition of sterol and sphingolipid biosynthesis. The flagella phenotype of the smp-1/smp-2(-/-) null mutant was reversed by re-expression of SMP-1, but not SMP-2. SMP-1 contains a jelly-roll beta-sheet structure that is probably conserved in all SMP proteins, and forms stable homo-oligomers in vivo. We propose that the SMP-1 coat generates and/or stabilizes sterol- and sphingolipid-rich domains in the flagellar membrane.
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Affiliation(s)
- Dedreia Tull
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
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Hayashi N, Titani K. N-myristoylated proteins, key components in intracellular signal transduction systems enabling rapid and flexible cell responses. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2010; 86:494-508. [PMID: 20467215 PMCID: PMC3108300 DOI: 10.2183/pjab.86.494] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 03/23/2010] [Indexed: 05/29/2023]
Abstract
N-myristoylation, one of the co- or post-translational modifications of proteins, has so far been regarded as necessary for anchoring of proteins to membranes. Recently, we have revealed that N(alpha)-myristoylation of several brain proteins unambiguously regulates certain protein-protein interactions that may affect signaling pathways in brain. Comparison of the amino acid sequences of myristoylated proteins including those in other organs suggests that this regulation is involved in signaling pathways not only in brain but also in other organs. Thus, it has been shown that myristoylated proteins in cells regulate the signal transduction between membranes and cytoplasmic fractions. An algorithm we have developed to identify myristoylated proteins in cells predicts the presence of hundreds of myristoylated proteins. Interestingly, a large portion of the myristoylated proteins thought to take part in signal transduction between membranes and cytoplasmic fractions are included in the predicted myristoylated proteins. If the proteins functionally regulated by myristoylation, a posttranslational protein modification, were understood as cross-talk points within the intracellular signal transduction system, known signaling pathways could thus be linked to each other, and a novel map of this intracellular network could be constructed. On the basis of our recent results, this review will highlight the multifunctional aspects of protein N-myristoylation in brain.
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Affiliation(s)
- Nobuhiro Hayashi
- Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama-shi, Kanagawa Pref., 226-8501, Japan.
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Munteanu CR, Vázquez JM, Dorado J, Sierra AP, Sánchez-González Á, Prado-Prado FJ, González-Díaz H. Complex Network Spectral Moments for ATCUN Motif DNA Cleavage: First Predictive Study on Proteins of Human Pathogen Parasites. J Proteome Res 2009; 8:5219-28. [DOI: 10.1021/pr900556g] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Cristian R. Munteanu
- Department of Information and Communication Technologies, Computer Science Faculty, University of A Coruña, Campus de Elviña, s/n 15071 A Coruña, Spain, Department of Inorganic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782 Santiago de Compostela, Spain, and Department of Microbiology & Parasitology, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782
| | - José M. Vázquez
- Department of Information and Communication Technologies, Computer Science Faculty, University of A Coruña, Campus de Elviña, s/n 15071 A Coruña, Spain, Department of Inorganic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782 Santiago de Compostela, Spain, and Department of Microbiology & Parasitology, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782
| | - Julián Dorado
- Department of Information and Communication Technologies, Computer Science Faculty, University of A Coruña, Campus de Elviña, s/n 15071 A Coruña, Spain, Department of Inorganic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782 Santiago de Compostela, Spain, and Department of Microbiology & Parasitology, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782
| | - Alejandro Pazos Sierra
- Department of Information and Communication Technologies, Computer Science Faculty, University of A Coruña, Campus de Elviña, s/n 15071 A Coruña, Spain, Department of Inorganic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782 Santiago de Compostela, Spain, and Department of Microbiology & Parasitology, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782
| | - Ángeles Sánchez-González
- Department of Information and Communication Technologies, Computer Science Faculty, University of A Coruña, Campus de Elviña, s/n 15071 A Coruña, Spain, Department of Inorganic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782 Santiago de Compostela, Spain, and Department of Microbiology & Parasitology, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782
| | - Francisco J. Prado-Prado
- Department of Information and Communication Technologies, Computer Science Faculty, University of A Coruña, Campus de Elviña, s/n 15071 A Coruña, Spain, Department of Inorganic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782 Santiago de Compostela, Spain, and Department of Microbiology & Parasitology, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782
| | - Humberto González-Díaz
- Department of Information and Communication Technologies, Computer Science Faculty, University of A Coruña, Campus de Elviña, s/n 15071 A Coruña, Spain, Department of Inorganic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782 Santiago de Compostela, Spain, and Department of Microbiology & Parasitology, Faculty of Pharmacy, University of Santiago de Compostela, Praza Seminario de Estudos Galegos, s/n. Campus sur, 15782
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Lim S, Peshenko I, Dizhoor A, Ames JB. Effects of Ca2+, Mg2+, and myristoylation on guanylyl cyclase activating protein 1 structure and stability. Biochemistry 2009; 48:850-62. [PMID: 19143494 PMCID: PMC2637916 DOI: 10.1021/bi801897p] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Guanylyl cyclase activating protein 1 (GCAP1), a member of the neuronal calcium sensor (NCS) subclass of the calmodulin superfamily, confers Ca(2+)-dependent activation of retinal guanylyl cylcase (RetGC) during phototransduction in vision. Here we analyze the energetics of Ca(2+) and Mg(2+) binding to the individual EF-hands, characterize metal-induced conformational changes, and evaluate structural effects of myristoylation as studied by isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). GCAP1 binds cooperatively to Ca(2+) at EF3 and EF4 (DeltaH(EF3) = -3.5 kcal/mol, and DeltaH(EF4) = -0.9 kcal/mol) with nanomolar affinity (K(EF3) = 80 nM, and K(EF4) = 200 nM), and a third Ca(2+) binds entropically at EF2 (DeltaH(EF2) = 3.1 kcal/mol, and K(EF2) = 0.9 microM). GCAP1 binds functionally to Mg(2+) at EF2 (DeltaH(EF2) = 4.3 kcal/mol, and K(EF2) = 0.7 mM) required for RetGC activation. Ca(2+) and/or Mg(2+) binding to GCAP1 dramatically alters DSC and NMR spectra, indicating metal-induced protein conformational changes in EF2, EF3, and EF4. Myristoylation of GCAP1 does not significantly alter its metal binding energetics or NMR spectra, suggesting that myristoylation does not influence the structure of the metal-binding EF-hands. Myristoylation also has almost no effect on protein folding stability measured by DSC. NMR resonances of myristate attached to GCAP1 are exchange-broadened, upfield-shifted, and insensitive to Ca(2+), consistent with the myristoyl group being sequestered inside the protein as seen in the crystal structure. We conclude that the protein environment near the myristate is not influenced by Mg(2+) or Ca(2+) binding but instead is constitutively dynamic and may play a role in promoting interactions of GCAP1 with the cyclase.
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Affiliation(s)
- Sunghyuk Lim
- Department of Chemistry, University of California, Davis, CA 95616
| | - Igor Peshenko
- Basic Sciences, Pennsylvania College of Optometry, Salus University, Elkins Park, PA 19027
| | - Alexander Dizhoor
- Basic Sciences, Pennsylvania College of Optometry, Salus University, Elkins Park, PA 19027
| | - James B. Ames
- Department of Chemistry, University of California, Davis, CA 95616
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