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Lacerda-Abreu MA, Dick CF, Meyer-Fernandes JR. The Role of Inorganic Phosphate Transporters in Highly Proliferative Cells: From Protozoan Parasites to Cancer Cells. MEMBRANES 2022; 13:42. [PMID: 36676849 PMCID: PMC9860751 DOI: 10.3390/membranes13010042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/01/2022] [Accepted: 12/26/2022] [Indexed: 06/17/2023]
Abstract
In addition to their standard inorganic phosphate (Pi) nutritional function, Pi transporters have additional roles in several cells, including Pi sensing (the so-called transceptor) and a crucial role in Pi metabolism, where they control several phenotypes, such as virulence in pathogens and tumour aggressiveness in cancer cells. Thus, intracellular Pi concentration should be tightly regulated by the fine control of intake and storage in organelles. Pi transporters are classified into two groups: the Pi transporter (PiT) family, also known as the Pi:Na+ symporter family; and the Pi:H+ symporter (PHS) family. Highly proliferative cells, such as protozoan parasites and cancer cells, rely on aerobic glycolysis to support the rapid generation of biomass, which is equated with the well-known Warburg effect in cancer cells. In protozoan parasite cells, Pi transporters are strongly associated with cell proliferation, possibly through their action as intracellular Pi suppliers for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity. Similarly, the growth rate hypothesis (GRH) proposes that the high Pi demands of tumours when achieving accelerated proliferation are mainly due to increased allocation to P-rich nucleic acids. The purpose of this review was to highlight recent advances in understanding the role of Pi transporters in unicellular eukaryotes and tumorigenic cells, correlating these roles with metabolism in these cells.
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Affiliation(s)
- Marco Antonio Lacerda-Abreu
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Claudia Fernanda Dick
- National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - José Roberto Meyer-Fernandes
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
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Carvalho-Kelly LF, Dick CF, Rocco-Machado N, Gomes-Vieira AL, Paes-Vieira L, Meyer-Fernandes JR. Anaerobic ATP synthesis pathways and inorganic phosphate transport and their possible roles in encystment in Acanthamoeba castellanii. Cell Biol Int 2022; 46:1288-1298. [PMID: 35673988 DOI: 10.1002/cbin.11830] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 12/12/2022]
Abstract
Acanthamoeba castellanii is the etiological agent of amoebic keratitis and is present in the environment in trophozoite or cyst forms. Both forms can infect the vertebrate host and colonize different tissues. The high resistance of cysts to standard drugs used in clinics contributes to the lack of effective treatments. Therefore, in this context, studies have emerged to understand cyst physiology and metabolism. Phosphate transporters are proteins responsible for the uptake of extracellular inorganic phosphate and transport to the cytosol. This work aims to verify the relationship between Pi transport and energetic metabolism in cysts of A. castellanii. The phosphate uptake ratio was higher in cysts compared with trophozoites. Recently, three sequences related to phosphate transporters have been identified in the A. castellanii genome (AcPHS1, AcPHS2, and AcPHS3); the messenger RNA expression levels of which differ depending on the amoeba life form. Pi uptake in cysts displayed peak activity at alkaline pH, whereas Pi transport in trophozoites was not affected in the same pH ranges. Cysts harbor a low-affinity Pi transport system (K0,5 and Vmax values of 1.76 ± 0.26 mM and 104.6 ± 6.3 nmol Pi × h-1 × 106 cells) compared to the trophozoite phosphate transport system. Pi transport seems important for anaerobic adenosine triphosphate synthesis in cysts, which initially occurs through the glycolytic pathway and subsequently through the pyruvate ferredoxin oxidoreductase pathway. Altogether, these results suggest that contrary to that previously postulated, cysts are active metabolic forms, and, as noted in trophozoites, phosphate uptake is important for energetic metabolism.
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Affiliation(s)
| | - Claudia Fernanda Dick
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Nathalia Rocco-Machado
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - André Luiz Gomes-Vieira
- Departamento de Bioquímica, Instituto de Química, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil
| | - Lisvane Paes-Vieira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
- Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), CCS, Bloco H, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Brazil
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Carvalho-de-Araújo AD, Carvalho-Kelly LF, Dick CF, Meyer-Fernandes JR. Inorganic phosphate transporter in Giardia duodenalis and its possible role in ATP synthesis. Mol Biochem Parasitol 2022; 251:111504. [PMID: 35843419 DOI: 10.1016/j.molbiopara.2022.111504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/14/2022] [Accepted: 07/13/2022] [Indexed: 10/17/2022]
Abstract
Giardia duodenalis is a flagellated protozoan that inhabits vertebrate host intestines, causing the disease known as giardiasis. Similar to other parasites, G. duodenalis must take advantage of environmental resources to survive, such as inorganic phosphate (Pi) availability. Pi is an anionic molecule and an essential nutrient for all organisms because it participates in the biosynthesis of biomolecules, energy storage, and cellular structure formation. The first step in Pi metabolism is its uptake through specific transporters on the plasma membrane. We identified a symporter H+:Pi-type ORF sequence in the G. duodenalis genome (GenBank ID: GL50803_5164), named GdPho84, which is homologous to Saccharomyces cerevisiae PHO84. In trophozoites, Pi transport was linear for up to 15 min, and the cell density was 3 × 107 cells/ml. Physiological variations in pH (6.4-8.0) did not influence Pi uptake. This Pi transporter had a high affinity, with K0.5 = 67.7 ± 7.1 µM Pi. SCH28080 (inhibitor of H+, K+-ATPase), bafilomycin A1 (inhibitor of vacuolar H+-ATPase), and FCCP (H+ ionophore) were able to inhibit Pi transport, indicating that an H+ gradient in the cell powered uphill Pi movement. PAA, an H+-dependent Pi transport inhibitor, reduced cell proliferation, Pi transport activity, and GdPHO48 mRNA levels. Pi starvation stimulated membrane potential-sensitive Pi uptake coupled to H+ fluxes, increased GdPho84 expression, and reduced intracellular ATP levels. These events indicate that these cells had an increased capacity to internalize Pi as a compensatory mechanism compared to cells maintained in control medium conditions. Internalized Pi can be used in glycolytic metabolism once iodoacetamide (GAPDH inhibitor) inhibits Pi influx. Together, these results reinforce the hypothesis that Pi is a crucial nutrient for G. duodenalis energy metabolism.
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Affiliation(s)
| | - Luiz Fernando Carvalho-Kelly
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil
| | - Claudia F Dick
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil.
| | - José Roberto Meyer-Fernandes
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil.
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Asady B, Dick CF, Ehrenman K, Sahu T, Romano JD, Coppens I. A single Na+-Pi cotransporter in Toxoplasma plays key roles in phosphate import and control of parasite osmoregulation. PLoS Pathog 2021; 16:e1009067. [PMID: 33383579 PMCID: PMC7817038 DOI: 10.1371/journal.ppat.1009067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 01/20/2021] [Accepted: 10/14/2020] [Indexed: 11/22/2022] Open
Abstract
Inorganic ions such as phosphate, are essential nutrients required for a broad spectrum of cellular functions and regulation. During infection, pathogens must obtain inorganic phosphate (Pi) from the host. Despite the essentiality of phosphate for all forms of life, how the intracellular parasite Toxoplasma gondii acquires Pi from the host cell is still unknown. In this study, we demonstrated that Toxoplasma actively internalizes exogenous Pi by exploiting a gradient of Na+ ions to drive Pi uptake across the plasma membrane. The Na+-dependent phosphate transport mechanism is electrogenic and functionally coupled to a cipargarmin sensitive Na+-H+-ATPase. Toxoplasma expresses one transmembrane Pi transporter harboring PHO4 binding domains that typify the PiT Family. This transporter named TgPiT, localizes to the plasma membrane, the inward buds of the endosomal organelles termed VAC, and many cytoplasmic vesicles. Upon Pi limitation in the medium, TgPiT is more abundant at the plasma membrane. We genetically ablated the PiT gene, and ΔTgPiT parasites are impaired in importing Pi and synthesizing polyphosphates. Interestingly, ΔTgPiT parasites accumulate 4-times more acidocalcisomes, storage organelles for phosphate molecules, as compared to parental parasites. In addition, these mutants have a reduced cell volume, enlarged VAC organelles, defects in calcium storage and a slightly alkaline pH. Overall, these mutants exhibit severe growth defects and have reduced acute virulence in mice. In survival mode, ΔTgPiT parasites upregulate several genes, including those encoding enzymes that cleave or transfer phosphate groups from phosphometabolites, transporters and ions exchangers localized to VAC or acidocalcisomes. Taken together, these findings point to a critical role of TgPiT for Pi supply for Toxoplasma and also for protection against osmotic stresses. Inorganic phosphate (Pi) is indispensable for the biosynthesis of key cellular components, and is involved in many metabolic and signaling pathways. Transport across the plasma membrane is the first step in the utilization of Pi. The import mechanism of Pi by the intracellular parasite Toxoplasma is unknown. We characterized a transmembrane, high-affinity Na+-Pi cotransporter, named TgPiT, expressed by the parasite at the plasma membrane for Pi uptake. Interestingly, TgPiT is also localized to inward buds of the endosomal VAC organelles and some cytoplasmic vesicles. Loss of TgPiT results in a severe reduction in Pi internalization and polyphosphate levels, but stimulation of the biogenesis of phosphate-enriched acidocalcisomes. ΔTgPiT parasites have a shrunken cell body, enlarged VAC organelles, poor release of stored calcium and a mildly alkaline pH, suggesting a role for TgPiT in the maintenance of overall ionic homeostasis. ΔTgPiT parasites are poorly infectious in vitro and in mice. The mutant appears to partially cope with the absence of TgPiT by up-regulating genes coding for ion transporters and enzymes catalyzing phosphate group transfer. Our data highlight a scenario in which the role of TgPiT in Pi and Na+ transport is functionally coupled with osmoregulation activities central to sustain Toxoplasma survival.
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Affiliation(s)
- Beejan Asady
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
| | - Claudia F. Dick
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
| | - Karen Ehrenman
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
| | - Tejram Sahu
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
| | - Julia D. Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore Maryland, United States of America
- * E-mail:
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The Functioning of Na +-ATPases from Protozoan Parasites: Are These Pumps Targets for Antiparasitic Drugs? Cells 2020; 9:cells9102225. [PMID: 33023071 PMCID: PMC7600311 DOI: 10.3390/cells9102225] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 12/17/2022] Open
Abstract
The ENA ATPases (from exitus natru: the exit of sodium) belonging to the P-type ATPases are structurally very similar to the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA); they exchange Na+ for H+ and, therefore, are also known as Na+-ATPases. ENA ATPases are required in alkaline milieu, as in the case for Aspergillus, where other transporters cannot mediate an uphill Na+ efflux. They are also important for salt tolerance, as described for Arabidopsis. During their life cycles, protozoan parasites might encounter a high pH environment, thus allowing consideration of ENA ATPases as possible targets for controlling certain severe parasitic diseases, such as Chagas' Disease. Phylogenetic analysis has now shown that, besides the types IIA, IIB, IIC, and IID P-type ATPases, there exists a 5th subgroup of ATPases classified as ATP4-type ATPases, found in Plasmodium falciparum and Toxoplasma gondii. In malaria, for example, some drugs targeting PfATP4 destroy Na+ homeostasis; these drugs, which include spiroindolones, are now in clinical trials. The ENA P-type (IID P-type ATPase) and ATP4-type ATPases have no structural homologue in mammalian cells, appearing only in fungi, plants, and protozoan parasites, e.g., Trypanosoma cruzi, Leishmania sp., Toxoplasma gondii, and Plasmodium falciparum. This exclusivity makes Na+-ATPase a potential candidate for the biologically-based design of new therapeutic interventions; for this reason, Na+-ATPases deserves more attention.
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Abstract
Phosphate is an essential nutrient for life and is a critical component of bone formation, a major signaling molecule, and structural component of cell walls. Phosphate is also a component of high-energy compounds (i.e., AMP, ADP, and ATP) and essential for nucleic acid helical structure (i.e., RNA and DNA). Phosphate plays a central role in the process of mineralization, normal serum levels being associated with appropriate bone mineralization, while high and low serum levels are associated with soft tissue calcification. The serum concentration of phosphate and the total body content of phosphate are highly regulated, a process that is accomplished by the coordinated effort of two families of sodium-dependent transporter proteins. The three isoforms of the SLC34 family (SLC34A1-A3) show very restricted tissue expression and regulate intestinal absorption and renal excretion of phosphate. SLC34A2 also regulates the phosphate concentration in multiple lumen fluids including milk, saliva, pancreatic fluid, and surfactant. Both isoforms of the SLC20 family exhibit ubiquitous expression (with some variation as to which one or both are expressed), are regulated by ambient phosphate, and likely serve the phosphate needs of the individual cell. These proteins exhibit similarities to phosphate transporters in nonmammalian organisms. The proteins are nonredundant as mutations in each yield unique clinical presentations. Further research is essential to understand the function, regulation, and coordination of the various phosphate transporters, both the ones described in this review and the phosphate transporters involved in intracellular transport.
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Affiliation(s)
- Nati Hernando
- University of Zurich-Irchel, Institute of Physiology, Zurich, Switzerland; Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; and Robley Rex VA Medical Center, Louisville, Kentucky
| | - Kenneth Gagnon
- University of Zurich-Irchel, Institute of Physiology, Zurich, Switzerland; Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; and Robley Rex VA Medical Center, Louisville, Kentucky
| | - Eleanor Lederer
- University of Zurich-Irchel, Institute of Physiology, Zurich, Switzerland; Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; and Robley Rex VA Medical Center, Louisville, Kentucky
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Carvalho-Kelly LF, Pralon CF, Rocco-Machado N, Nascimento MT, Carvalho-de-Araújo AD, Meyer-Fernandes JR. Acanthamoeba castellanii phosphate transporter (AcPHS) is important to maintain inorganic phosphate influx and is related to trophozoite metabolic processes. J Bioenerg Biomembr 2020; 52:93-102. [PMID: 31965457 DOI: 10.1007/s10863-020-09822-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/03/2020] [Indexed: 10/25/2022]
Abstract
Acanthamoeba castellanii is a free-living amoeba and the etiological agent of granulomatous amoebic encephalitis and amoebic keratitis. A. castellanii can be present as trophozoites or cysts. The trophozoite is the vegetative form of the cell and has great infective capacity compared to the cysts, which are the dormant form that protect the cell from environmental changes. Phosphate transporters are a group of proteins that are able to internalize inorganic phosphate from the extracellular to intracellular medium. Plasma membrane phosphate transporters are responsible for maintaining phosphate homeostasis, and in some organisms, regulating cellular growth. The aim of this work was to biochemically characterize the plasma membrane phosphate transporter in A. castellanii and its role in cellular growth and metabolism. To measure inorganic phosphate (Pi) uptake, trophozoites were grown in liquid PYG medium at 28 °C for 2 days. The phosphate uptake was measured by the rapid filtration of intact cells incubated with 0.5 μCi of 32Pi for 1 h. The Pi transport was linear as a function of time and exhibited Michaelis-Menten kinetics with a Km = 88.78 ± 6.86 μM Pi and Vmax = 547.5 ± 16.9 Pi × h-1 × 10-6 cells. A. castellanii presented linear phosphate uptake up to 1 h with a cell density ranging from 1 × 105 to 2 × 106 amoeba × ml-1. The Pi uptake was higher in the acidic pH range than in the alkaline range. The oxygen consumption of living trophozoites increased according to Pi addition to the extracellular medium. When the cells were treated with FCCP, no effect from Pi on the oxygen flow was observed. The addition of increasing Pi concentrations not only increased oxygen consumption but also increased the intracellular ATP pool. These phenomena were abolished when the cells were treated with FCCP or exposed to hypoxia. Together, these results reinforce the hypothesis that Pi is a key nutrient for Acanthamoeba castellanii metabolism.
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Affiliation(s)
- Luiz Fernando Carvalho-Kelly
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil
| | - Clara Ferreira Pralon
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil
| | - Nathalia Rocco-Machado
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil
| | | | - Ayra Diandra Carvalho-de-Araújo
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil. .,Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), CCS, Bloco H, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil.
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Carvalho-Kelly LF, Gomes-Vieira AL, Paes-Vieira L, da Silva ADZ, Meyer-Fernandes JR. Leishmania amazonensis inorganic phosphate transporter system is increased in the proliferative forms. Mol Biochem Parasitol 2019; 233:111212. [PMID: 31445076 DOI: 10.1016/j.molbiopara.2019.111212] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 08/13/2019] [Accepted: 08/19/2019] [Indexed: 11/27/2022]
Abstract
Here we characterize a high-affinity Pi transport system energized by a H+ gradient in Leishmania amazonensis. Pi uptake and transcription of LamPho84 gene are differentially regulated during parasite life cycle. Our data suggest that Pi acquisition could be a pivotal task for the success of the parasite throughout its life cycle.
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Affiliation(s)
| | - André Luiz Gomes-Vieira
- Instituto de Química, Departamento de Bioquímica, Universidade Federal Rural do Rio de Janeiro, Brazil
| | - Lisvane Paes-Vieira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), Rio de Janeiro, Brazil.
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Dos-Santos ALA, Dick CF, Lopes LR, Rocco-Machado N, Muzi-Filho H, Freitas-Mesquita AL, Paes-Vieira L, Vieyra A, Meyer-Fernandes JR. Tartrate-resistant phosphatase type 5 in Trypanosoma cruzi is important for resistance to oxidative stress promoted by hydrogen peroxide. Exp Parasitol 2019; 205:107748. [PMID: 31442453 DOI: 10.1016/j.exppara.2019.107748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 08/01/2019] [Accepted: 08/19/2019] [Indexed: 11/28/2022]
Abstract
Trypanosoma cruzi (the causative agent of Chagas disease) presents a complex life cycle that involves adaptations in vertebrate and invertebrate hosts. As a protozoan parasite of hematophagous insects and mammalian hosts, T. cruzi is exposed to reactive oxygen species (ROS). To investigate the functionality of T. cruzi tartrate-resistant acid phosphatase type 5 (TcACP5), we cloned, superexpressed and purified the enzyme. Purified TcACP5 exhibited a Vmax and apparent Km for pNPP hydrolysis of 7.7 ± 0.2 nmol pNP × μg-1 × h-1 and 169.3 ± 22.6 μM, respectively. The pH dependence was characterized by sharp maximal activity at pH 5.0, and inhibition assays demonstrated its sensitivity to acid phosphatase inhibitors. Similar activities were obtained with saturating concentrations of P-Ser and P-Thr as substrates. The enzyme metabolizes hydrogen peroxide (H2O2) in vitro, and parasites superexpressing this enzyme were more resistant to oxidative stress promoted by H2O2. Taken together, these results suggest that TcACP5 plays a central role in phosphoryl transfer and redox reactions.
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Affiliation(s)
- André L A Dos-Santos
- Leopoldo De Meis Medical Biochemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Science and Technology for Structural Biology and Bioimaging (INBEB), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Claudia F Dick
- Leopoldo De Meis Medical Biochemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Science and Technology for Structural Biology and Bioimaging (INBEB), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leandro R Lopes
- Leopoldo De Meis Medical Biochemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Paulo de Góes Microbiology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Science and Technology for Structural Biology and Bioimaging (INBEB), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nathália Rocco-Machado
- Leopoldo De Meis Medical Biochemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Science and Technology for Structural Biology and Bioimaging (INBEB), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Humberto Muzi-Filho
- Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Anita L Freitas-Mesquita
- Leopoldo De Meis Medical Biochemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Science and Technology for Structural Biology and Bioimaging (INBEB), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lisvane Paes-Vieira
- Leopoldo De Meis Medical Biochemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Science and Technology for Structural Biology and Bioimaging (INBEB), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adalberto Vieyra
- Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Graduate Program in Translational Biomedicine, Grande Rio University, Duque de Caxias, Brazil
| | - José Roberto Meyer-Fernandes
- Leopoldo De Meis Medical Biochemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Science and Technology for Structural Biology and Bioimaging (INBEB), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
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Intersection of phosphate transport, oxidative stress and TOR signalling in Candida albicans virulence. PLoS Pathog 2018; 14:e1007076. [PMID: 30059535 PMCID: PMC6085062 DOI: 10.1371/journal.ppat.1007076] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 08/09/2018] [Accepted: 05/07/2018] [Indexed: 12/11/2022] Open
Abstract
Phosphate is an essential macronutrient required for cell growth and division. Pho84 is the major high-affinity cell-surface phosphate importer of Saccharomyces cerevisiae and a crucial element in the phosphate homeostatic system of this model yeast. We found that loss of Candida albicans Pho84 attenuated virulence in Drosophila and murine oropharyngeal and disseminated models of invasive infection, and conferred hypersensitivity to neutrophil killing. Susceptibility of cells lacking Pho84 to neutrophil attack depended on reactive oxygen species (ROS): pho84-/- cells were no more susceptible than wild type C. albicans to neutrophils from a patient with chronic granulomatous disease, or to those whose oxidative burst was pharmacologically inhibited or neutralized. pho84-/- mutants hyperactivated oxidative stress signalling. They accumulated intracellular ROS in the absence of extrinsic oxidative stress, in high as well as low ambient phosphate conditions. ROS accumulation correlated with diminished levels of the unique superoxide dismutase Sod3 in pho84-/- cells, while SOD3 overexpression from a conditional promoter substantially restored these cells’ oxidative stress resistance in vitro. Repression of SOD3 expression sharply increased their oxidative stress hypersensitivity. Neither of these oxidative stress management effects of manipulating SOD3 transcription was observed in PHO84 wild type cells. Sod3 levels were not the only factor driving oxidative stress effects on pho84-/- cells, though, because overexpressing SOD3 did not ameliorate these cells’ hypersensitivity to neutrophil killing ex vivo, indicating Pho84 has further roles in oxidative stress resistance and virulence. Measurement of cellular metal concentrations demonstrated that diminished Sod3 expression was not due to decreased import of its metal cofactor manganese, as predicted from the function of S. cerevisiae Pho84 as a low-affinity manganese transporter. Instead of a role of Pho84 in metal transport, we found its role in TORC1 activation to impact oxidative stress management: overexpression of the TORC1-activating GTPase Gtr1 relieved the Sod3 deficit and ROS excess in pho84-/- null mutant cells, though it did not suppress their hypersensitivity to neutrophil killing or hyphal growth defect. Pharmacologic inhibition of Pho84 by small molecules including the FDA-approved drug foscarnet also induced ROS accumulation. Inhibiting Pho84 could hence support host defenses by sensitizing C. albicans to oxidative stress. Candida albicans is the species most often isolated from patients with invasive fungal disease, and is also a common colonizer of healthy people. It is well equipped to compete for nutrients with bacteria co-inhabiting human gastrointestinal mucous membranes, since it possesses multiple transporters to internalize important nutrients like sugars, nitrogen sources, and phosphate. During infection, the fungus needs to withstand human defense cells that attack it with noxious chemicals, among which reactive oxygen species (ROS) are critical. We found that a high-affinity phosphate transporter, Pho84, is required for C. albicans’ ability to successfully invade animal hosts and to eliminate ROS. Levels of a fungal enzyme that breaks down ROS, Sod3, were decreased in cells lacking Pho84. A connection between this phosphate transporter and the ROS-detoxifying enzyme was identified in the Target of Rapamycin (TOR) pathway, to which Pho84 is known to provide activating signals when phosphate is abundant. Small molecules that block Pho84 activity impair the ability of C. albicans to detoxify ROS. Since humans manage phosphate differently than fungi and have no Pho84 homolog, a drug that inhibits Pho84 could disable the defense of the fungus against the host.
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Russo-Abrahão T, Lacerda-Abreu MA, Gomes T, Cosentino-Gomes D, Carvalho-de-Araújo AD, Rodrigues MF, de Oliveira ACL, Rumjanek FD, Monteiro RDQ, Meyer-Fernandes JR. Characterization of inorganic phosphate transport in the triple-negative breast cancer cell line, MDA-MB-231. PLoS One 2018; 13:e0191270. [PMID: 29415049 PMCID: PMC5802448 DOI: 10.1371/journal.pone.0191270] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 01/02/2018] [Indexed: 12/05/2022] Open
Abstract
Background Recent studies demonstrate that interstitial inorganic phosphate is significantly elevated in the breast cancer microenvironment as compared to normal tissue. In addition it has been shown that breast cancer cells express high levels of the NaPi-IIb carrier (SLC34A2), suggesting that this carrier may play a role in breast cancer progression. However, the biochemical behavior of inorganic phosphate (Pi) transporter in this cancer type remains elusive. Methods In this work, we characterize the kinetic parameters of Pi transport in the aggressive human breast cancer cell line, MDA-MB-231, and correlated Pi transport with cell migration and adhesion. Results We determined the influence of sodium concentration, pH, metabolic inhibitors, as well as the affinity for inorganic phosphate in Pi transport. We observed that the inorganic phosphate is dependent on sodium transport (K0,5 value = 21.98 mM for NaCl). Furthermore, the transport is modulated by different pH values and increasing concentrations of Pi, following the Michaelis-Menten kinetics (K0,5 = 0.08 mM Pi). PFA, monensin, furosemide and ouabain inhibited Pi transport, cell migration and adhesion. Conclusions Taken together, these results showed that the uptake of Pi in MDA-MB-231 cells is modulated by sodium and by regulatory mechanisms of intracellular sodium gradient. General Significance: Pi transport might be regarded as a potential target for therapy against tumor progression.
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Affiliation(s)
- Thais Russo-Abrahão
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Marco Antônio Lacerda-Abreu
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Tainá Gomes
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Daniela Cosentino-Gomes
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Ayra Diandra Carvalho-de-Araújo
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Mariana Figueiredo Rodrigues
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Ana Carolina Leal de Oliveira
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Franklin David Rumjanek
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Robson de Queiroz Monteiro
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo De Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
- * E-mail:
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12
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Russo-Abrahão T, Koeller CM, Steinmann ME, Silva-Rito S, Marins-Lucena T, Alves-Bezerra M, Lima-Giarola NL, de-Paula IF, Gonzalez-Salgado A, Sigel E, Bütikofer P, Gondim KC, Heise N, Meyer-Fernandes JR. H +-dependent inorganic phosphate uptake in Trypanosoma brucei is influenced by myo-inositol transporter. J Bioenerg Biomembr 2017; 49:183-194. [PMID: 28185085 DOI: 10.1007/s10863-017-9695-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 01/22/2017] [Indexed: 10/20/2022]
Abstract
Trypanosoma brucei is an extracellular protozoan parasite that causes human African trypanosomiasis or "sleeping sickness". During the different phases of its life cycle, T. brucei depends on exogenous inorganic phosphate (Pi), but little is known about the transport of Pi in this organism. In the present study, we showed that the transport of 32Pi across the plasma membrane follows Michaelis-Menten kinetics and is modulated by pH variation, with higher activity at acidic pH. Bloodstream forms presented lower Pi transport in comparison to procyclic forms, that displayed an apparent K0.5 = 0.093 ± 0.008 mM. Additionally, FCCP (H+-ionophore), valinomycin (K+-ionophore) and SCH28080 (H+, K+-ATPase inhibitor) inhibited the Pi transport. Gene Tb11.02.3020, previously described to encode the parasite H+:myo-inositol transporter (TbHMIT), was hypothesized to be potentially involved in the H+:Pi cotransport because of its similarity with the Pho84 transporter described in S. cerevisiae and other trypanosomatids. Indeed, the RNAi mediated knockdown remarkably reduced TbHMIT gene expression, compromised cell growth and decreased Pi transport by half. In addition, Pi transport was inhibited when parasites were incubated in the presence of concentrations of myo-inositol that are above 300 μM. However, when expressed in Xenopus laevis oocytes, two-electrode voltage clamp experiments provided direct electrophysiological evidence that the protein encoded by TbHMIT is definitely a myo-inositol transporter that may be only marginally affected by the presence of Pi. These results confirmed the presence of a Pi carrier in T. brucei, similar to the H+-dependent inorganic phosphate system described in S. cerevisiae and other trypanosomatids. This transport system contributes to the acquisition of Pi and may be involved in the growth and survival of procyclic forms. In summary, this work presents the first description of a Pi transport system in T. brucei.
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Affiliation(s)
- Thais Russo-Abrahão
- Instituto de Microbiologia Professor Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.,Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Carolina Macedo Koeller
- Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Michael E Steinmann
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Stephanie Silva-Rito
- Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Thaissa Marins-Lucena
- Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Michele Alves-Bezerra
- Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil
| | - Naira Ligia Lima-Giarola
- Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - Iron Francisco de-Paula
- Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil
| | - Amaia Gonzalez-Salgado
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Erwin Sigel
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Katia Calp Gondim
- Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil
| | - Norton Heise
- Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil.
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil. .,Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil.
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13
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Vieira-Bernardo R, Gomes-Vieira AL, Carvalho-Kelly LF, Russo-Abrahão T, Meyer-Fernandes JR. The biochemical characterization of two phosphate transport systems in Phytomonas serpens. Exp Parasitol 2016; 173:1-8. [PMID: 27956087 DOI: 10.1016/j.exppara.2016.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 11/01/2016] [Accepted: 12/08/2016] [Indexed: 10/20/2022]
Abstract
Inorganic phosphate (Pi) is an essential nutrient for all organisms because it is required for a variety of biochemical processes, such as signal transduction and the synthesis of phosphate-containing biomolecules. Assays of 32Pi uptake performed in the absence or in the presence of Na+ indicated the existence of a Na+-dependent and a Na+-independent Pi transporter in Phytomonas serpens. Phylogenetic analysis of two hypothetical protein sequences of Phytomonas (EM1) showed similarities to the high-affinity Pi transporters of Saccharomyces cerevisiae: Pho84, a Na+-independent Pi transporter, and Pho89, a Na+-dependent Pi transporter. Plasma membrane depolarization by FCCP, an H+ ionophore, strongly decreased Pi uptake via both Na+-independent and Na+-dependent carriers, indicating that a membrane potential is essential for Pi influx. In addition, the furosemide-sensitive Na+-pump activity in the cells grown in low Pi conditions was found to be higher than the activity detected in the plasma membrane of cells cultivated at high Pi concentration, suggesting that the up-regulation of the Na+-ATPase pump could be related to the increase of Pi uptake by the Pho89p Na+:Pi symporter. Here we characterize for the first time two inorganic phosphate transporters powered by Na+ and H+ gradients and activated by low Pi availability in the phytopathogen P. serpens.
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Affiliation(s)
- Rodrigo Vieira-Bernardo
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - André Luiz Gomes-Vieira
- Instituto de Ciências Exatas, Departamento de Química, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil
| | - Luiz Fernando Carvalho-Kelly
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Thais Russo-Abrahão
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil
| | - José Roberto Meyer-Fernandes
- Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil.
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14
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Jimenez V, Docampo R. TcPho91 is a contractile vacuole phosphate sodium symporter that regulates phosphate and polyphosphate metabolism in Trypanosoma cruzi. Mol Microbiol 2015; 97:911-25. [PMID: 26031800 DOI: 10.1111/mmi.13075] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2015] [Indexed: 02/03/2023]
Abstract
We have identified a phosphate transporter (TcPho91) localized to the bladder of the contractile vacuole complex (CVC) of Trypanosoma cruzi, the etiologic agent of Chagas disease. TcPho91 has 12 transmembrane domains, an N-terminal regulatory SPX (named after SYG1, Pho81 and XPR1) domain and an anion permease domain. Functional expression in Xenopus laevis oocytes followed by two-electrode voltage clamp showed that TcPho91 is a low-affinity transporter with a Km for Pi in the millimolar range, and sodium-dependency. Epimastigotes overexpressing TcPho91-green fluorescent protein have significantly higher levels of pyrophosphate (PPi ) and short-chain polyphosphate (polyP), suggesting accumulation of Pi in these cells. Moreover, when overexpressing parasites were maintained in a medium with low Pi , they grew at higher rates than control parasites. Only one allele of TcPho91 in the CL strain encodes for the complete open reading frame, while the other one is truncated encoding for only the N-terminal domain. Taking advantage of this characteristic, knockdown experiments were performed resulting in cells with reduced growth rate as well as a reduction in PPi and short-chain polyP levels. Our results indicate that TcPho91 is a phosphate sodium symporter involved in Pi homeostasis in T. cruzi.
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Affiliation(s)
- Veronica Jimenez
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, 30602, USA.,Department of Biological Science, California State University Fullerton, Fullerton, CA, 92831b, USA
| | - Roberto Docampo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, 30602, USA
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15
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Kinetic and biochemical characterization of Trypanosoma evansi nucleoside triphosphate diphosphohydrolase. Exp Parasitol 2015; 153:98-104. [DOI: 10.1016/j.exppara.2015.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 03/19/2015] [Accepted: 03/20/2015] [Indexed: 11/17/2022]
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16
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Dick CF, Dos-Santos ALA, Meyer-Fernandes JR. Inorganic phosphate uptake in unicellular eukaryotes. Biochim Biophys Acta Gen Subj 2014; 1840:2123-7. [PMID: 24674820 DOI: 10.1016/j.bbagen.2014.03.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 02/27/2014] [Accepted: 03/17/2014] [Indexed: 11/18/2022]
Abstract
BACKGROUND Inorganic phosphate (Pi) is an essential nutrient for all organisms. The route of Pi utilization begins with Pi transport across the plasma membrane. SCOPE OF REVIEW Here, we analyzed the gene sequences and compared the biochemical profiles, including kinetic and modulator parameters, of Pi transporters in unicellular eukaryotes. The objective of this review is to evaluate the recent findings regarding Pi uptake mechanisms in microorganisms, such as the fungi Neurospora crassa and Saccharomyces cerevisiae and the parasite protozoans Trypanosoma cruzi, Trypanosoma rangeli, Leishmania infantum and Plasmodium falciparum. MAJOR CONCLUSION Pi uptake is the key step of Pi homeostasis and in the subsequent signaling event in eukaryotic microorganisms. GENERAL SIGNIFICANCE Biochemical and structural studies are important for clarifying mechanisms of Pi homeostasis, as well as Pi sensor and downstream pathways, and raise possibilities for future studies in this field.
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Affiliation(s)
- Claudia F Dick
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA.
| | - André L A Dos-Santos
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - José R Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil.
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17
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Jimenez V. Dealing with environmental challenges: mechanisms of adaptation in Trypanosoma cruzi. Res Microbiol 2014; 165:155-65. [PMID: 24508488 DOI: 10.1016/j.resmic.2014.01.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 01/27/2014] [Indexed: 10/25/2022]
Abstract
Protozoan parasites have a significant impact upon global health, infecting millions of people around the world. With limited therapeutic options and no vaccines available, research efforts are focused upon unraveling cellular mechanisms essential for parasite survival. During its life cycle, Trypanosoma cruzi, the causal agent of Chagas disease, is exposed to multiple external conditions and different hosts. Environmental cues are linked to the differentiation process allowing the parasite to complete its life cycle. Successful transmission depends on the ability of the cells to trigger adaptive responses and cope with stressors while regulating proliferation and transition to different life stages. This review focuses upon different aspects of the stress response in T. cruzi, proposing new hypotheses regarding cross-talk and cross-tolerance with respect to environmental changes and discussing open questions and future directions.
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Affiliation(s)
- Veronica Jimenez
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, McCarthy Hall 307, 92831 Fullerton, CA, USA.
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