H+-dependent inorganic phosphate uptake in Trypanosoma brucei is influenced by myo-inositol transporter

Russo‐Abrahão, Thais; Koeller, Carolina M.; Steinmann, Michael E.; Silva-Rito, Stephanie; Marins-Lucena, Thaissa; Auger, Michèle; Lima-Giarola, Naira Ligia; de-Paula, Iron Francisco; González-Salgado, Amaia; Sigel, Erwin; Bütikofer, Peter; Gondim, Kátia C.; Heise, Norton; Meyer‐Fernandes, José Roberto

doi:10.1007/s10863-017-9695-y

Cited by 16 publications

(14 citation statements)

References 58 publications

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“…Pathogenic unicellular parasites require intact Pi homeostasis for development and virulence [ 9 , 11 , 14 , 54 ], as do bacterial pathogens [ 55 ]. Among fungi, representatives of all extant lineages possess core components of the PHO regulon, including high-affinity H+-Pi symporters like Pho84 [ 56 ].…”

Section: Discussionmentioning

confidence: 99%

Intersection of phosphate transport, oxidative stress and TOR signalling in Candida albicans virulence

et al. 2018

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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.

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Section: Discussionmentioning

confidence: 99%

Intersection of phosphate transport, oxidative stress and TOR signalling in Candida albicans virulence

et al. 2018

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“…Loss of TgPiT results in the up-regulation of several transporters/carriers, although their transferred ligands remain to be identified, e.g., carrier superfamily protein TGGT1_235650; Log 2 fold change (logFC): 1.6), two Major Facilitator Superfamily proteins (TGGT1_216710; LogFC: 1.6 and TGGT1_266870; LogFC: 0.9), and two ABC transporters (TGGT1_239020; LogFC: 0.7 and TGGT1_263740; LogFC: 0.5). Interestingly, the gene product of TGGT1_216710 shares 27% identity with the P i :H + symporter (PHS) member: H + -linked myoinositol transporter from Trypanosoma brucei (TbHMIT) [50].…”

Section: δTgpit Parasites Have Altered Gene Transcription To Assist Imentioning

confidence: 99%

“…In unicellular eukaryotes, the second main P i transporter is the P i :H + symporter (PHS) (TC No. 2.A.1.9.1), which is included in the Major Facilitator Superfamily (MFS), such as yeast PHO84 [68], PHO-5 from Neurospora crassa [69] and TbHMIT from Trypanosoma brucei [50]. Interestingly, in ΔTgPiT parasites, a MFS protein (TGGT1_216710) is up-regulated,…”

Section: Plos Pathogensmentioning

confidence: 99%

A single Na+-Pi cotransporter in Toxoplasma plays key roles in phosphate import and control of parasite osmoregulation

et al. 2020

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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.

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“…It was recently demonstrated in other cell types [ 26 , 33 , 34 ] that some inhibitors of Pi transport, such as FCCP, valinomycin and SCH28080, could have metabolic effects at the mitochondrial level leading to severe ATP depletion, thus indirectly affecting the active Pi uptake. Therefore, we measured the intracellular ATP content under Pi transport conditions, in the absence or presence of monensin, furosemide, ouabain and PFA, which inhibit Pi transport in MDA-MB-231 cells.…”

Section: Discussionmentioning

confidence: 99%

Characterization of inorganic phosphate transport in the triple-negative breast cancer cell line, MDA-MB-231

Russo‐Abrahão¹,

Lacerda-Abreu²,

Gomes³

et al. 2018

PLoS ONE

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BackgroundRecent 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.MethodsIn 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.ResultsWe 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.ConclusionsTaken 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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H+-dependent inorganic phosphate uptake in Trypanosoma brucei is influenced by myo-inositol transporter

Cited by 16 publications

References 58 publications

Intersection of phosphate transport, oxidative stress and TOR signalling in Candida albicans virulence

Intersection of phosphate transport, oxidative stress and TOR signalling in Candida albicans virulence

A single Na+-Pi cotransporter in Toxoplasma plays key roles in phosphate import and control of parasite osmoregulation

Characterization of inorganic phosphate transport in the triple-negative breast cancer cell line, MDA-MB-231

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