Transcriptional regulation of phosphate-responsive genes in low-affinity phosphate-transporter-defective mutants in Saccharomyces cerevisiae

Auesukaree, Choowong; Homma, Tomoyuki; Kaneko, Yoshinobu; Harashima, Satoshi

doi:10.1016/s0006-291x(03)01068-4

Cited by 61 publications

(63 citation statements)

References 25 publications

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“…An increased resistance of the ⌬pho87, ⌬pho90, and ⌬pho91 mutants has been previously reported by Pinson et al (8). Several studies have shown that mutations in the low affinity phosphate transporters resulted in derepression of the PHOregulated genes (8,10,28), leading to increased transcription of PHO84 and to inactivation of the low affinity transporters through derepression of SPL2. Thus, in these mutants, Pho84p is responsible for most of the phosphate uptake, whatever the phosphate conditions.…”

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confidence: 51%

“…In agreement with previous studies (10), we observed that in P i -limited medium the triple-disruptant strain exhibited a 2-fold higher V max of P i uptake than the wild-type strain (Table 2). It was shown that the higher activity in this strain was accompanied by enhanced transcription of the PHO84 gene (10). Increased activity of Pho84p, in phosphate and selenite transport, explains the higher sensitivity of this strain to selenite as compared with the wild-type cells.…”

Section: Discussionmentioning

confidence: 78%

“…In S. cerevisiae, the inorganic phosphate (P i ) acquisition system is composed of five transporters (9). Three of them (Pho87p, Pho90p, and Pho91p) are constitutively transcribed and take up phosphate with low affinity (10). The high affinity transport system, composed of Pho84p and Pho89p, is transcriptionally up-regulated by the phosphate signal transduction (PHO) 2 pathway in response to P i starvation (11)(12)(13).…”

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confidence: 99%

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Uptake of Selenite by Saccharomyces cerevisiae Involves the High and Low Affinity Orthophosphate Transporters

Lazard

Blanquet

Fisicaro

et al. 2010

Journal of Biological Chemistry

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Although the general cytotoxicity of selenite is well established, the mechanism by which this compound crosses cellular membranes is still unknown. Here, we show that in Saccharomyces cerevisiae, the transport system used opportunistically by selenite depends on the phosphate concentration in the growth medium. Both the high and low affinity phosphate transporters are involved in selenite uptake. When cells are grown at low P i concentrations, the high affinity phosphate transporter Pho84p is the major contributor to selenite uptake. When phosphate is abundant, selenite is internalized through the low affinity P i transporters (Pho87p, Pho90p, and Pho91p). Accordingly, inactivation of the high affinity phosphate transporter Pho84p results in increased resistance to selenite and reduced uptake in low P i medium, whereas deletion of SPL2, a negative regulator of low affinity phosphate uptake, results in exacerbated sensitivity to selenite. Measurements of the kinetic parameters for selenite and phosphate uptake demonstrate that there is a competition between phosphate and selenite ions for both P i transport systems. In addition, our results indicate that Pho84p is very selective for phosphate as compared with selenite, whereas the low affinity transporters discriminate less efficiently between the two ions. The properties of phosphate and selenite transport enable us to propose an explanation to the paradoxical increase of selenite toxicity when phosphate concentration in the growth medium is raised above 1 mM.Although toxic at high concentrations, selenium is required in many cells, because it is translationally incorporated as selenocysteine into selenoproteins that perform specific and essential functions (1). Cells must ensure selenium uptake to sustain this metabolism. However, little is known about selenium transport. Because selenium and sulfur are chalcogen elements that have many chemical properties in common, selenium shares metabolic pathways with sulfur. Accordingly, selenate was shown to be taken up by the yeast Saccharomyces cerevisiae sulfate permeases (2). Similarly, in plants, selenate is taken up by roots via the high affinity sulfate transporters (3).On the other hand, specific selenite transporters have never been identified so far. The sulfate ABC transporter of Escherichia coli mediates selenite uptake in addition to that of selenate (4). However, repression of the expression of that transporter does not quench selenite uptake completely, indicating that an alternative entry pathway exists for selenite (5). In S. cerevisiae, which does not possess selenoproteins, an energy-dependent uptake of selenite, distinct from that of selenate, was reported. Characterization of the kinetics of selenite uptake suggested the existence of two transport systems: a high affinity system at low selenite concentration and a low affinity system at higher concentration (6). Recently, a study of selenite uptake by wheat (Triticum aestivum) roots showed it to be an active process competitively inhibited by phosph...

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confidence: 51%

Section: Discussionmentioning

confidence: 78%

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confidence: 99%

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Uptake of Selenite by Saccharomyces cerevisiae Involves the High and Low Affinity Orthophosphate Transporters

Lazard

Blanquet

Fisicaro

et al. 2010

Journal of Biological Chemistry

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“…However, more recently, Pho91 was shown to be a vacuolar phosphate transporter (Hurlimann et al 2007). Mutations in the low-affinity phosphate transporter genes led to upregulation of phosphate-regulated genes (Auesukaree et al 2003;Pinson et al 2004). Importantly, this transcriptional response was not associated with a lower intracellular phosphate concentration, suggesting that these transporters contribute to phosphate sensing independently of internal phosphate concentration (Pinson et al 2004).…”

Section: Role Of An Intermediate Metabolite (Ip7) In the Regulation Omentioning

confidence: 99%

Regulation of Amino Acid, Nucleotide, and Phosphate Metabolism in Saccharomyces cerevisiae

2012

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Ever since the beginning of biochemical analysis, yeast has been a pioneering model for studying the regulation of eukaryotic metabolism. During the last three decades, the combination of powerful yeast genetics and genome-wide approaches has led to a more integrated view of metabolic regulation. Multiple layers of regulation, from suprapathway control to individual gene responses, have been discovered. Constitutive and dedicated systems that are critical in sensing of the intra- and extracellular environment have been identified, and there is a growing awareness of their involvement in the highly regulated intracellular compartmentalization of proteins and metabolites. This review focuses on recent developments in the field of amino acid, nucleotide, and phosphate metabolism and provides illustrative examples of how yeast cells combine a variety of mechanisms to achieve coordinated regulation of multiple metabolic pathways. Importantly, common schemes have emerged, which reveal mechanisms conserved among various pathways, such as those involved in metabolite sensing and transcriptional regulation by noncoding RNAs or by metabolic intermediates. Thanks to the remarkable sophistication offered by the yeast experimental system, a picture of the intimate connections between the metabolomic and the transcriptome is becoming clear.

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“…Under prolonged Pi deficient conditions, both growth and cell division of S. cerevisiae will eventually be arrested, referred as the quiescent G 0 -state. In budding yeast, the Pi acquisition system is composed of four cell membrane localized Pi transporters, with the two low affinity Pi transporters, namely Pho87, Pho90 being ubiquitously expressed [5], while the two high affinity Pi transporters, Pho84 and Pho89 are regulated by the PHO pathway (Table 1) [1,2,[6][7][8]. Pho91, initially considered as part of the low Pi affinity uptake system was recently shown to be localized on the tonoplast and involved in exporting Pi from the vacuole to the cytosol [9].…”

Section: Introductionmentioning

confidence: 99%

Phosphate homeostasis in the yeast Saccharomyces cerevisiae, the key role of the SPX domain‐containing proteins

et al. 2012

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a b s t r a c tIn the yeast Saccharomyces cerevisiae, a working model for nutrient homeostasis in eukaryotes, inorganic phosphate (Pi) homeostasis is regulated by the PHO pathway, a set of phosphate starvation induced genes, acting to optimize Pi uptake and utilization. Among these, a subset of proteins containing the SPX domain has been shown to be key regulators of Pi homeostasis. In this review, we summarize the recent progresses in elucidating the mechanisms controlling Pi homeostasis in yeast, focusing on the key roles of the SPX domain-containing proteins in these processes, as well as describing the future challenges and opportunities in this fast-moving field.

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Transcriptional regulation of phosphate-responsive genes in low-affinity phosphate-transporter-defective mutants in Saccharomyces cerevisiae

Cited by 61 publications

References 25 publications

Uptake of Selenite by Saccharomyces cerevisiae Involves the High and Low Affinity Orthophosphate Transporters

Uptake of Selenite by Saccharomyces cerevisiae Involves the High and Low Affinity Orthophosphate Transporters

Regulation of Amino Acid, Nucleotide, and Phosphate Metabolism in Saccharomyces cerevisiae

Phosphate homeostasis in the yeast Saccharomyces cerevisiae, the key role of the SPX domain‐containing proteins

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