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Santana-Filho AP, Pereira AJ, Laibida LA, Souza-Melo N, DaRocha WD, Sassaki GL. Lipidomic Analysis Reveals Branched-Chain and Cyclic Fatty Acids from Angomonas deanei Grown under Different Nutritional and Physiological Conditions. Molecules 2024; 29:3352. [PMID: 39064928 PMCID: PMC11280109 DOI: 10.3390/molecules29143352] [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: 06/05/2024] [Revised: 07/03/2024] [Accepted: 07/12/2024] [Indexed: 07/28/2024] Open
Abstract
Angomonas deanei belongs to Trypanosomatidae family, a family of parasites that only infect insects. It hosts a bacterial endosymbiont in a mutualistic relationship, constituting an excellent model for studying organelle origin and cellular evolution. A lipidomic approach, which allows for a comprehensive analysis of all lipids in a biological system (lipidome), is a useful tool for identifying and measuring different expression patterns of lipid classes. The present study applied GC-MS and NMR techniques, coupled with principal component analysis (PCA), in order to perform a comparative lipidomic study of wild and aposymbiotic A. deanei grown in the presence or absence of FBS. Unusual contents of branched-chain iso C17:0 and C19:0-cis-9,10 and-11,12 fatty acids were identified in A. deanei cultures, and it was interesting to note that their content slightly decreased at the log phase culture, indicating that in the latter growth stages the cell must promote the remodeling of lipid synthesis in order to maintain the fluidity of the membrane. The combination of analytical techniques used in this work allowed for the detection and characterization of lipids and relevant contributors in a variety of A. deanei growth conditions.
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Affiliation(s)
| | | | | | | | - Wanderson Duarte DaRocha
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba 81531-980, PR, Brazil; (A.P.S.-F.); (A.J.P.)
| | - Guilherme Lanzi Sassaki
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba 81531-980, PR, Brazil; (A.P.S.-F.); (A.J.P.)
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Nath SK, Pankajakshan P, Sharma T, Kumari P, Shinde S, Garg N, Mathur K, Arambam N, Harjani D, Raj M, Kwatra G, Venkatesh S, Choudhoury A, Bano S, Tayal P, Sharan M, Arora R, Strych U, Hotez PJ, Bottazzi ME, Rawal K. A Data-Driven Approach to Construct a Molecular Map of Trypanosoma cruzi to Identify Drugs and Vaccine Targets. Vaccines (Basel) 2023; 11:vaccines11020267. [PMID: 36851145 PMCID: PMC9963959 DOI: 10.3390/vaccines11020267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 01/28/2023] Open
Abstract
Chagas disease (CD) is endemic in large parts of Central and South America, as well as in Texas and the southern regions of the United States. Successful parasites, such as the causative agent of CD, Trypanosoma cruzi have adapted to specific hosts during their phylogenesis. In this work, we have assembled an interactive network of the complex relations that occur between molecules within T. cruzi. An expert curation strategy was combined with a text-mining approach to screen 10,234 full-length research articles and over 200,000 abstracts relevant to T. cruzi. We obtained a scale-free network consisting of 1055 nodes and 874 edges, and composed of 838 proteins, 43 genes, 20 complexes, 9 RNAs, 36 simple molecules, 81 phenotypes, and 37 known pharmaceuticals. Further, we deployed an automated docking pipeline to conduct large-scale docking studies involving several thousand drugs and potential targets to identify network-based binding propensities. These experiments have revealed that the existing FDA-approved drugs benznidazole (Bz) and nifurtimox (Nf) show comparatively high binding energies to the T. cruzi network proteins (e.g., PIF1 helicase-like protein, trans-sialidase), when compared with control datasets consisting of proteins from other pathogens. We envisage this work to be of value to those interested in finding new vaccines for CD, as well as drugs against the T. cruzi parasite.
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Affiliation(s)
- Swarsat Kaushik Nath
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Preeti Pankajakshan
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Trapti Sharma
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Priya Kumari
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Sweety Shinde
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Nikita Garg
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Kartavya Mathur
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Nevidita Arambam
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Divyank Harjani
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Manpriya Raj
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Garwit Kwatra
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Sayantan Venkatesh
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Alakto Choudhoury
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Saima Bano
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Prashansa Tayal
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Mahek Sharan
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Ruchika Arora
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
| | - Ulrich Strych
- Texas Children’s Hospital Center for Vaccine Development, Departments of Pediatrics and Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Peter J. Hotez
- Texas Children’s Hospital Center for Vaccine Development, Departments of Pediatrics and Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Biology, Baylor University, Waco, TX 76798, USA
| | - Maria Elena Bottazzi
- Texas Children’s Hospital Center for Vaccine Development, Departments of Pediatrics and Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Biology, Baylor University, Waco, TX 76798, USA
| | - Kamal Rawal
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida 201303, Uttar Pradesh, India
- Correspondence:
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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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Zhang Y, Huang Y, Srivathsan A, Lim TK, Lin Q, He CY. The unusual flagellar-targeting mechanism and functions of the trypanosome ortholog of the ciliary GTPase Arl13b. J Cell Sci 2018; 131:jcs.219071. [PMID: 30097558 PMCID: PMC6140319 DOI: 10.1242/jcs.219071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 07/28/2018] [Indexed: 12/11/2022] Open
Abstract
The small GTPase Arl13b is one of the most conserved and ancient ciliary proteins. In human and animals, Arl13b is primarily associated with the ciliary membrane, where it acts as a guanine-nucleotide-exchange factor (GEF) for Arl3 and is implicated in a variety of ciliary and cellular functions. We have identified and characterized Trypanosoma brucei (Tb)Arl13, the sole Arl13b homolog in this evolutionarily divergent, protozoan parasite. TbArl13 has conserved flagellar functions and exhibits catalytic activity towards two different TbArl3 homologs. However, TbArl13 is distinctly associated with the axoneme through a dimerization/docking (D/D) domain. Replacing the D/D domain with a sequence encoding a flagellar membrane protein created a viable alternative to the wild-type TbArl13 in our RNA interference (RNAi)-based rescue assay. Therefore, flagellar enrichment is crucial for TbArl13, but mechanisms to achieve this could be flexible. Our findings thus extend the understanding of the roles of Arl13b and Arl13b–Arl3 pathway in a divergent flagellate of medical importance. This article has an associated First Person interview with the first author of the paper. Highlighted Article: All roads lead to cilia – how the essential flagellar enrichment of Arl13 is achieved in trypanosome cells using a fundamentally different strategy compared with that of animal cells.
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Affiliation(s)
- Yiliu Zhang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Yameng Huang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Amrita Srivathsan
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Teck Kwang Lim
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Qingsong Lin
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Cynthia Y He
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
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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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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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Docampo R, Huang G. Calcium signaling in trypanosomatid parasites. Cell Calcium 2014; 57:194-202. [PMID: 25468729 DOI: 10.1016/j.ceca.2014.10.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 10/27/2014] [Accepted: 10/29/2014] [Indexed: 11/29/2022]
Abstract
Calcium ion (Ca(2+)) is an important second messenger in trypanosomatids and essential for their survival although prolonged high intracellular Ca(2+) levels lead to cell death. As other eukaryotic cells, trypanosomes use two sources of Ca(2+) for generating signals: Ca(2+) release from intracellular stores and Ca(2+) entry across the plasma membrane. Ca(2+) release from intracellular stores is controlled by the inositol 1,4,5-trisphosphate receptor (IP3R) that is located in acidocalcisomes, acidic organelles that are the primary Ca(2+) reservoir in these cells. A plasma membrane Ca(2+)-ATPase controls the cytosolic Ca(2+) levels and a number of pumps and exchangers are responsible for Ca(2+) uptake and release from intracellular compartments. The trypanosomatid genomes contain a wide variety of signaling and regulatory proteins that bind Ca(2+) as well as many Ca(2+)-binding proteins that await further characterization. The mitochondrial Ca(2+) transporters of trypanosomatids have an important role in the regulation of cell bioenergetics and flagellar Ca(2+) appears to have roles in sensing the environment. In trypanosomatids in which an intracellular life cycle is present, Ca(2+) signaling is important for host cell invasion.
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Affiliation(s)
- Roberto Docampo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA 30620, USA; Departamento de Patologia Clínica, State University of Campinas, Campinas, SP 13083, Brazil.
| | - Guozhong Huang
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA 30620, USA
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