scholarly journals Lack of Control in Inorganic Phosphate Uptake by Catharanthus roseus (L.) G. Don Cells (Cytoplasmic Inorganic Phosphate Homeostasis Depends on the Tonoplast Inorganic Phosphate Transport System?)

1995 ◽  
Vol 108 (1) ◽  
pp. 295-302 ◽  
Author(s):  
K. Sakano ◽  
Y. Yazaki ◽  
K. Okihara ◽  
T. Mimura ◽  
S. Kiyota
Keyword(s):  
Transport System ◽  
Catharanthus Roseus ◽  
Inorganic Phosphate ◽  
Phosphate Uptake ◽  
Phosphate Transport ◽  
Phosphate Homeostasis ◽  
Lack Of Control

Phosphate uptake by renal membrane vesicles of rabbits adapted to high and low phosphorus diets

1983 ◽  
Vol 245 (2) ◽  
pp. F175-F180 ◽  
Author(s):  
L. Cheng ◽  
C. T. Liang ◽  
B. Sacktor
Keyword(s):  
Transport System ◽  
Phosphate Uptake ◽  
Membrane Vesicles ◽  
Phosphate Transport ◽  
Uptake System ◽  
Low Phosphorus ◽  
Dietary Phosphate ◽  
Preferred Species ◽  
Uptake Medium ◽  
Phosphate Carrier

Renal adaptation to changes in phosphate intake was studied by comparing phosphate uptake by proximal tubule brush border membrane vesicles from rabbits on a relatively high or low phosphorus diet. The low phosphorus diet increased Na+ gradient-dependent phosphate uptake. Uptake in the absence of Na+ and in the presence of Na+, but no gradient, was not significantly affected. The phosphorus diet did not alter Na+ gradient-dependent D-glucose and L-proline uptake. The low phosphorus diet increased Vmax; affinity for phosphate was not appreciably changed. At all concentrations of extravesicular Na+, phosphate uptake was higher in membrane vesicles from animals fed the low phosphorus diet; the kinetics of the phosphate uptake system, with respect to Na+, was also altered by the change in dietary phosphate. These findings suggest that adaptation involves an alteration in the rate of translocation of the Na+-phosphate carrier when energized by a Na+ gradient driving force rather than a change in the number of Na+-phosphate carrier sites. With membrane vesicles from rabbits fed a low phosphorus diet, phosphate uptake increased several-fold when the pH of the uptake medium was raised, whereas with membrane vesicles from animals fed a high phosphorus diet the enhancement of uptake with alkalinization was relatively small. Irrespective of the diet, divalent phosphate was the probable preferred species for transport. Dietary adaptation was associated, however, with an alteration in the pH dependency of the transport system per se. These findings provide evidence that the adaptation of the kidney phosphate transport system to dietary phosphate load involves an intrinsic change in the Na+-phosphate carrier.

Characterization of inorganic phosphate transport in osteoclast-like cells

2005 ◽  
Vol 288 (4) ◽  
pp. C921-C931 ◽  
Author(s):  
Mikiko Ito ◽  
Naoko Matsuka ◽  
Michiyo Izuka ◽  
Sakiko Haito ◽  
Yuko Sakai ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Transport System ◽  
Inorganic Phosphate ◽  
Phosphate Transport ◽  
Transport Systems ◽  
Raw264.7 Cells ◽  
Transport Activity ◽  
Phosphonoformic Acid ◽  
Carbonyl Cyanide ◽  
Bone Particles

Osteoclasts possess inorganic phosphate (Pi) transport systems to take up external Pi during bone resorption. In the present study, we characterized Pi transport in mouse osteoclast-like cells that were obtained by differentiation of macrophage RAW264.7 cells with receptor activator of NF-κB ligand (RANKL). In undifferentiated RAW264.7 cells, Pi transport into the cells was Na+ dependent, but after treatment with RANKL, Na+-independent Pi transport was significantly increased. In addition, compared with neutral pH, the activity of the Na+-independent Pi transport system in the osteoclast-like cells was markedly enhanced at pH 5.5. The Na+-independent system consisted of two components with Km of 0.35 mM and 7.5 mM. The inhibitors of Pi transport, phosphonoformic acid, and arsenate substantially decreased Pi transport. The proton ionophores nigericin and carbonyl cyanide p-trifluoromethoxyphenylhydrazone as well as a K+ ionophore, valinomycin, significantly suppressed Pi transport activity. Analysis of BCECF fluorescence indicated that Pi transport in osteoclast-like cells is coupled to a proton transport system. In addition, elevation of extracellular K+ ion stimulated Pi transport, suggesting that membrane voltage is involved in the regulation of Pi transport activity. Finally, bone particles significantly increased Na+-independent Pi transport activity in osteoclast-like cells. Thus, osteoclast-like cells have a Pi transport system with characteristics that are different from those of other Na+-dependent Pi transporters. We conclude that stimulation of Pi transport at acidic pH is necessary for bone resorption or for production of the large amounts of energy necessary for acidification of the extracellular environment.

scholarly journals Evidence for the transport of zinc(II) ions via the Pit inorganic phosphate transport system inEscherichia coli

2000 ◽  
Vol 184 (2) ◽  
pp. 231-235 ◽  
Author(s):  
Steven J. Beard ◽  
Rohani Hashim ◽  
Guanghui Wu ◽  
Marie R.B. Binet ◽  
Martin N. Hughes ◽  
...  
Keyword(s):  
Transport System ◽  
Inorganic Phosphate ◽  
Phosphate Transport ◽  
Inescherichia Coli

scholarly journals Role of Phosphate Transport System Component PstB1 in Phosphate Internalization by Nostoc punctiforme

2016 ◽  
Vol 82 (21) ◽  
pp. 6344-6356 ◽  
Author(s):  
L. Hudek ◽  
D. Premachandra ◽  
W. A. J. Webster ◽  
L. Bräu
Keyword(s):  
Transport System ◽  
Phosphate Uptake ◽  
Phosphate Transport ◽  
Mrna Levels ◽  
Nostoc Punctiforme ◽  
Content Type ◽  
Phosphate Accumulation ◽  
Phosphate Availability ◽  
In Cells

ABSTRACTIn bacteria, limited phosphate availability promotes the synthesis of active uptake systems, such as the Pst phosphate transport system. To understand the mechanisms that facilitate phosphate accumulation in the cyanobacteriumNostoc punctiforme, phosphate transport systems were identified, revealing a redundancy of Pst phosphate uptake systems that exists across three distinct operons. Four separate PstB system components were identified.pstB1was determined to be a suitable target for creating phenotypic mutations that could result in the accumulation of excessive levels of phosphate through its overexpression or in a reduction of the capacity to accumulate phosphate through its deletion. Using quantitative real-time PCR (qPCR), it was determined thatpstB1mRNA levels increased significantly over 64 h in cells cultured in 0 mM added phosphate and decreased significantly in cells exposed to high (12.8 mM) phosphate concentrations compared to the level in cells cultured under normal (0.8 mM) conditions. Possible compensation for the loss of PstB1 was observed whenpstB2,pstB3, andpstB4mRNA levels increased, particularly in cells starved of phosphate. The overexpression ofpstB1increased phosphate uptake byN. punctiformeand was shown to functionally complement the loss of PstB inE. coliPstB knockout (PstB−) mutants. The knockout ofpstB1inN. punctiformedid not have a significant effect on cellular phosphate accumulation or growth for the most part, which is attributed to the compensation for the loss of PstB1 by alterations in thepstB2,pstB3, andpstB4mRNA levels. This study provides novelin vivoevidence that PstB1 plays a functional role in phosphate uptake inN. punctiforme.IMPORTANCECyanobacteria have been evolving over 3.5 billion years and have become highly adept at growing under limiting nutrient levels. Phosphate is crucial for the survival and prosperity of all organisms. In bacteria, limited phosphate availability promotes the synthesis of active uptake systems. The Pst phosphate transport system is one such system, responsible for the internalization of phosphate when cells are in phosphate-limited environments. Our investigations reveal the presence of multiple Pst phosphate uptake systems that exist across three distinct operons inNostoc punctiformeand functionally characterize the role of the gene product PstB1 as being crucial for the maintenance of phosphate accumulation. We demonstrate that the genespstB2,pstB3, andpstB4show alterations in expression to compensate for the deletion ofpstB1. The overall outcomes of this work provide insights as to the complex transport mechanisms that exist in cyanobacteria likeN. punctiforme, allowing them to thrive in low-phosphate environments.

scholarly journals Copper tolerance mediated by polyphosphate degradation and low-affinity inorganic phosphate transport system in Escherichia coli

2014 ◽  
Vol 14 (1) ◽  
pp. 72 ◽  
Author(s):  
Mariana Grillo-Puertas ◽  
Lici Schurig-Briccio ◽  
Luisa Rodríguez-Montelongo ◽  
María Rintoul ◽  
Viviana Rapisarda
Keyword(s):  
Escherichia Coli ◽  
Transport System ◽  
Inorganic Phosphate ◽  
Phosphate Transport ◽  
Copper Tolerance ◽  
Polyphosphate Degradation

scholarly journals Molecular Mechanisms of Phosphate Sensing, Transport and Signalling in Streptomyces and Related Actinobacteria

2021 ◽  
Vol 22 (3) ◽  
pp. 1129
Author(s):  
Juan Francisco Martín ◽  
Paloma Liras
Keyword(s):  
Transport System ◽  
Inorganic Phosphate ◽  
Molecular Mechanisms ◽  
Phosphate Transport ◽  
Transport Systems ◽  
Outer Side ◽  
Phosphate Binding ◽  
Streptomyces Species ◽  
High Affinity ◽  
Sugar Phosphates

Phosphorous, in the form of phosphate, is a key element in the nutrition of all living beings. In nature, it is present in the form of phosphate salts, organophosphates, and phosphonates. Bacteria transport inorganic phosphate by the high affinity phosphate transport system PstSCAB, and the low affinity PitH transporters. The PstSCAB system consists of four components. PstS is the phosphate binding protein and discriminates between arsenate and phosphate. In the Streptomyces species, the PstS protein, attached to the outer side of the cell membrane, is glycosylated and released as a soluble protein that lacks its phosphate binding ability. Transport of phosphate by the PstSCAB system is drastically regulated by the inorganic phosphate concentration and mediated by binding of phosphorylated PhoP to the promoter of the PstSCAB operon. In Mycobacterium smegmatis, an additional high affinity transport system, PhnCDE, is also under PhoP regulation. Additionally, Streptomyces have a duplicated low affinity phosphate transport system encoded by the pitH1–pitH2 genes. In this system phosphate is transported as a metal-phosphate complex in simport with protons. Expression of pitH2, but not that of pitH1 in Streptomyces coelicolor, is regulated by PhoP. Interestingly, in many Streptomyces species, three gene clusters pitH1–pstSCAB–ppk (for a polyphosphate kinase), are linked in a supercluster formed by nine genes related to phosphate metabolism. Glycerol-3-phosphate may be transported by the actinobacteria Corynebacterium glutamicum that contains a ugp gene cluster for glycerol-3-P uptake, but the ugp cluster is not present in Streptomyces genomes. Sugar phosphates and nucleotides are used as phosphate source by the Streptomyces species, but there is no evidence of the uhp gene involved in the transport of sugar phosphates. Sugar phosphates and nucleotides are dephosphorylated by extracellular phosphatases and nucleotidases. An isolated uhpT gene for a hexose phosphate antiporter is present in several pathogenic corynebacteria, such as Corynebacterium diphtheriae, but not in non-pathogenic ones. Phosphonates are molecules that contains phosphate linked covalently to a carbon atom through a very stable C–P bond. Their utilization requires the phnCDE genes for phosphonates/phosphate transport and genes for degradation, including those for the subunits of the C–P lyase. Strains of the Arthrobacter and Streptomyces genera were reported to degrade simple phosphonates, but bioinformatic analysis reveals that whole sets of genes for putative phosphonate degradation are present only in three Arthrobacter species and a few Streptomyces species. Genes encoding the C–P lyase subunits occur in several Streptomyces species associated with plant roots or with mangroves, but not in the laboratory model Streptomyces species; however, the phnCDE genes that encode phosphonates/phosphate transport systems are frequent in Streptomyces species, suggesting that these genes, in the absence of C–P lyase genes, might be used as surrogate phosphate transporters. In summary, Streptomyces and related actinobacteria seem to be less versatile in phosphate transport systems than Enterobacteria.

scholarly journals Phosphate Transport and Sensing in Saccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 159 (4) ◽  
pp. 1491-1499 ◽  
Author(s):  
Dennis D Wykoff ◽  
Erin K O'Shea
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Inorganic Phosphate ◽  
Phosphate Uptake ◽  
Phosphate Starvation ◽  
Phosphate Transport ◽  
Glucose Sensors ◽  
Phosphate Transporters ◽  
Synthetic Lethal ◽  
High Phosphate

Abstract Cellular metabolism depends on the appropriate concentration of intracellular inorganic phosphate; however, little is known about how phosphate concentrations are sensed. The similarity of Pho84p, a high-affinity phosphate transporter in Saccharomyces cerevisiae, to the glucose sensors Snf3p and Rgt2p has led to the hypothesis that Pho84p is an inorganic phosphate sensor. Furthermore, pho84Δ strains have defects in phosphate signaling; they constitutively express PHO5, a phosphate starvation-inducible gene. We began these studies to determine the role of phosphate transporters in signaling phosphate starvation. Previous experiments demonstrated a defect in phosphate uptake in phosphate-starved pho84Δ cells; however, the pho84Δ strain expresses PHO5 constitutively when grown in phosphate-replete media. We determined that pho84Δ cells have a significant defect in phosphate uptake even when grown in high phosphate media. Overexpression of unrelated phosphate transporters or a glycerophosphoinositol transporter in the pho84Δ strain suppresses the PHO5 constitutive phenotype. These data suggest that PHO84 is not required for sensing phosphate. We further characterized putative phosphate transporters, identifying two new phosphate transporters, PHO90 and PHO91. A synthetic lethal phenotype was observed when five phosphate transporters were inactivated, and the contribution of each transporter to uptake in high phosphate conditions was determined. Finally, a PHO84-dependent compensation response was identified; the abundance of Pho84p at the plasma membrane increases in cells that are defective in other phosphate transporters.

Physiological control of phosphate uptake and phosphate homeostasis in plant cells

2001 ◽  
Vol 28 (7) ◽  
pp. 655 ◽  
Author(s):  
Tetsuro Mimura
Keyword(s):  
Plasma Membrane ◽  
Driving Force ◽  
Inorganic Phosphate ◽  
Phosphate Uptake ◽  
Plant Cells ◽  
Phosphate Homeostasis ◽  
Physiological Control ◽  
Physiological Level ◽  
Pi Transport ◽  
Cytoplasmic Acidification

Inorganic phosphate (Pi) uptake systems across the plasma membrane of plant cells have been extensively investigated. Physiological studies have established that Pi is transported into plant cells via co-transport with H+ , and in some plants with Na + , using the driving force provided by the electrogenic H + pump in the plasma membrane. Molecular studies have identified many genes for Pi transporters and are providing insights into the mechanisms of genetic control of Pi transport. There still remain, however, questions as to how Pi uptake systems are regulated at the physiological level. We have found that Pi uptake induces cytoplasmic acidification, and, conversely, that inducing cytoplasmic acidification causes the cytoplasmic Pi concentration to decrease. Both of these responses affect the operation of the H + -pump. These phenomena are discussed in relation to a possible mechanism for the physiological control of Pi uptake by plant cells.

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