Inorganic phosphate uptake in unicellular eukaryotes

Dick, Claudia F.; Dos-Santos, André L.A.; Meyer‐Fernandes, José Roberto

doi:10.1016/j.bbagen.2014.03.014

Cited by 36 publications

(30 citation statements)

References 51 publications

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“…Overall, expression levels of phosphate transporters were higher in the P-limited treatment, but were not statistically different in the N-limited treatment, compared to the replete treatment (Figure 3E ). The most highly expressed gene in the P-limited treatment was one of two genes that were annotated as putative pho4 family genes, a high-affinity sodium-phosphate transporter family that is generally regulated by phosphorous starvation in fungi (Dick et al, 2014 ) (Supplemental Figure 2 ). The expression level of this gene was higher in the P-limited treatment compared to the replete treatment.…”

Section: Resultsmentioning

confidence: 99%

Changes in gene expression of Prymnesium parvum induced by nitrogen and phosphorus limitation

et al. 2015

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Prymnesium parvum is a globally distributed prymnesiophyte alga commonly found in brackish water marine ecosystems and lakes. It possesses a suite of toxins with ichthyotoxic, cytotoxic and hemolytic effects which, along with its mixotrophic nutritional capabilities, allows it to form massive Ecosystem Disruptive Algal Blooms (EDABs). While blooms of high abundance coincide with high levels of nitrogen (N) and phosphorus (P), reports of field and laboratory studies have noted that P. parvum toxicity appears to be augmented at high N:P ratios or P-limiting conditions. Here we present the results of a comparative analysis of P. parvum RNA-Seq transcriptomes under nutrient replete conditions, and N or P deficiency to understand how this organism responds at the transcriptional level to varying nutrient conditions. In nutrient limited conditions we found diverse transcriptional responses for genes involved in nutrient uptake, protein synthesis and degradation, photosynthesis, and toxin production. As anticipated, when either N or P was limiting, transcription levels of genes encoding transporters for the respective nutrient were higher than those under replete condition. Ribosomal and lysosomal protein genes were expressed at higher levels under either nutrient-limited condition compared to the replete condition. Photosynthesis genes and polyketide synthase genes were more highly expressed under P-limitation but not under N-limitation. These results highlight the ability of P. parvum to mount a coordinated and varied cellular and physiological response to nutrient limitation. Results also provide potential marker genes for further evaluating the physiological response and toxin production of P. parvum populations during bloom formation or to changing environmental conditions.

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Section: Resultsmentioning

confidence: 99%

Changes in gene expression of Prymnesium parvum induced by nitrogen and phosphorus limitation

et al. 2015

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“…Two high-affinity Pi uptake systems act in fungi; H + /Pi transporters homologous to PHT1 proteins and Na + /Pi transporters homologous to PTB proteins are active in Pi uptake in low external Pi conditions in N. crassa, S. cerevisiae and Yarrowia lipolytica. Differences in pH optima and counter-ion selectivity of the fungal Na + /Pi and H + /Pi symporters have led to the hypothesis that different transporters are active in different environmental conditions, providing the organisms with a wide adaptive range (Versaw, 1995;Zvyagilskaya & Persson, 2003;Dick et al, 2014). This could also be true in streptophyte algae and early diverging land plants, where both PHT1 and core PTB proteins are probably active in Pi uptake.…”

Section: Researchmentioning

confidence: 99%

“…Phosphorus is absorbed largely as inorganic phosphate (Pi), through Pi transporters located at the plasma membrane of cells at the interface with the external environment. High-affinity and low-affinity Pi transporters catalyse Pi uptake from environments containing micromolar and millimolar concentrations of Pi, respectively (Werner et al, 1998;Harris et al, 2001;Werner & Kinne, 2001;Bucher, 2006;Dick et al, 2014). Chlorophytes and streptophytes are two monophyletic clades that constitute the green plant lineage.…”

Section: Introductionmentioning

confidence: 99%

Functional PTB phosphate transporters are present in streptophyte algae and early diverging land plants

et al. 2017

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SummaryTwo inorganic phosphate (Pi) uptake mechanisms operate in streptophytes and chlorophytes, the two lineages of green plants. PHOSPHATE TRANSPORTER B (PTB) proteins are hypothesized to be the Na + /Pi symporters catalysing Pi uptake in chlorophytes, whereas PHOSPHATE TRANSPORTER 1 (PHT1) proteins are the H + /Pi symporters that carry out Pi uptake in angiosperms. PHT1 proteins are present in all streptophyte lineages. However, Pi uptake in streptophyte algae and marine angiosperms requires Na + influx, suggesting that Na + /Pi symporters also function in some streptophytes. We tested the hypothesis that Na + /Pi symporters exist in streptophytes. We identified PTB sequences in streptophyte genomes. Core PTB proteins are present at the plasma membrane of the liverwort Marchantia polymorpha. The expression of M. polymorpha core PTB proteins in the Saccharomyces cerevisiae pho2 mutant defective in high-affinity Pi transport rescues growth in low-Pi environments. Moreover, levels of core PTB mRNAs of M. polymorpha and the streptophyte alga Coleochaete nitellarum are higher in low-Pi than in Pi-replete conditions, consistent with a role in Pi uptake from the environment.We conclude that land plants inherited two Pi uptake mechanisms -mediated by the PTB and PHT1 proteins, respectively -from their streptophyte algal ancestor. Both systems operate in parallel in extant early diverging land plants.

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“…This signature sequence is highlighted with red letters in Figure 1A. The human proteins from this family are thought to be involved in housekeeping functions and are called PiT1 and PiT2, whereas the Neurospora crassa and Saccharomyces cerevisiae members are called Pho-4 and Pho89, respectively [32,33]. Mutations in the signature sequence of the PiT2 protein block Pi transport [34].…”

Section: Pita and Pitb-the Low-affinity Pi Importersmentioning

confidence: 99%

Molecular Mechanisms of Phosphate Homeostasis in <i>Escherichia coli</i>

McCleary¹

2017

≪i>Escherichia Coli

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Life's processes absolutely require inorganic phosphate for structural and energetic purposes. Escherichia coli has developed sophisticated mechanisms to acquire phosphate and to maintain intracellular amounts at optimal levels. The processes by which these simple cells maintain stable intracellular concentrations of phosphate are termed phosphate homeostasis, which involves mechanisms to balance the import, assimilation, sequestration, and export of phosphate. This chapter introduces the proteins involved in phosphate homeostasis and reviews information concerning the multiple phosphate transporters and the mechanisms by which they are regulated. It also introduces new concepts of how this bacterium responds to elevated extracellular levels of phosphate and presents a model for the integration of all of these processes to achieve homeostasis. The predominant importers are PitA, PitB, and the PstSCAB complex. Assimilation, or the incorporation of Pi into organic molecules, occurs primarily through the formation of ATP. Gene regulation relies on the PhoB/PhoR two-component system and the formation of a signaling complex at the membrane. The amount of intracellular phosphate can be fine-tuned through the formation or degradation of polyphosphate. Polyphosphate formation requires adequate supplies of ATP. In addition, when intracellular phosphate levels become too high, phosphate can be exported through PitA, PitB, or the YjbB transporters.

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Inorganic phosphate uptake in unicellular eukaryotes

Cited by 36 publications

References 51 publications

Changes in gene expression of Prymnesium parvum induced by nitrogen and phosphorus limitation

Changes in gene expression of Prymnesium parvum induced by nitrogen and phosphorus limitation

Functional PTB phosphate transporters are present in streptophyte algae and early diverging land plants

Molecular Mechanisms of Phosphate Homeostasis in <i>Escherichia coli</i>

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