scholarly journals Regulation of Copper Metabolism by Nitrogen Utilization in Saccharomyces cerevisiae

2021 ◽  
Vol 7 (9) ◽  
pp. 756
Author(s):  
Suzie Kang ◽  
Hyewon Seo ◽  
Min-Gyu Lee ◽  
Cheol-Won Yun
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Iron Uptake ◽  
Nitrogen Starvation ◽  
Copper Metabolism ◽  
Nitrogen Utilization ◽  
Deletion Mutants ◽  
Uptake System ◽  
Wild Type ◽  
High Affinity ◽  
Uptake Activity

To understand the relationship between carbon or nitrogen utilization and iron homeostasis, we performed an iron uptake assay with several deletion mutants with partial defects in carbon or nitrogen metabolism. Among them, some deletion mutants defective in carbon metabolism partially and the MEP2 deletion mutant showed lower iron uptake activity than the wild type. Mep2 is known as a high-affinity ammonia transporter in Saccharomyces cerevisiae. Interestingly, we found that nitrogen starvation resulted in lower iron uptake activity than that of wild-type cells without downregulation of the genes involved in the high-affinity iron uptake system FET3/FTR1. However, the gene expression of FRE1 and CTR1 was downregulated by nitrogen starvation. The protein level of Ctr1 was also decreased by nitrogen starvation, and addition of copper to the nitrogen starvation medium partially restored iron uptake activity. However, the expression of MAC1, which is a copper-responsive transcriptional activator, was not downregulated by nitrogen starvation at the transcriptional level but was highly downregulated at the translational level. Mac1 was downregulated dramatically under nitrogen starvation, and treatment with MG132, which is an inhibitor of proteasome-dependent protein degradation, partially attenuated the downregulation of Mac1. Taken together, these results suggest that nitrogen starvation downregulates the high-affinity iron uptake system by degrading Mac1 in a proteasome-dependent manner and eventually downregulates copper metabolism.

scholarly journals Genetic evidence that ferric reductase is required for iron uptake in Saccharomyces cerevisiae.

1990 ◽  
Vol 10 (5) ◽  
pp. 2294-2301 ◽  
Author(s):  
A Dancis ◽  
R D Klausner ◽  
A G Hinnebusch ◽  
J G Barriocanal
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Plasma Membrane ◽  
Iron Uptake ◽  
Reductase Activity ◽  
Gene Transcript ◽  
Single Mutation ◽  
Uptake System ◽  
Ferric Reductase ◽  
Wild Type ◽  
Iron Starvation

The requirement for a reduction step in cellular iron uptake has been postulated, and the existence of plasma membrane ferric reductase activity has been described in both procaryotic and eucaryotic cells. In the yeast Saccharomyces cerevisiae, there is an externally directed reductase activity that is regulated by the concentration of iron in the growth medium; maximal activity is induced by iron starvation. We report here the isolation of a mutant of S. cerevisiae lacking the reductase activity. This mutant is deficient in the uptake of ferric iron and is extremely sensitive to iron deprivation. Genetic analysis of the mutant demonstrates that the reductase and ferric uptake deficiencies are due to a single mutation that we designate fre1-1. Both phenotypes cosegregate in meiosis, corevert with a frequency of 10(-7), and are complemented by a 3.5-kilobase fragment of genomic DNA from wild-type S. cerevisiae. This fragment contains FRE1, the wild-type allele of the mutant gene. The level of the gene transcript is regulated by iron in the same was as the reductase activity. The ferrous ion product of the reductase must traverse the plasma membrane. A high-affinity (Km = 5 microM) ferrous uptake system is present in both wild-type and mutant cells. Thus, iron uptake in S. cerevisiae is mediated by two plasma membrane components, a reductase and a ferrous transport system.

Genetic evidence that ferric reductase is required for iron uptake in Saccharomyces cerevisiae

1990 ◽  
Vol 10 (5) ◽  
pp. 2294-2301
Author(s):  
A Dancis ◽  
R D Klausner ◽  
A G Hinnebusch ◽  
J G Barriocanal
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Plasma Membrane ◽  
Iron Uptake ◽  
Reductase Activity ◽  
Gene Transcript ◽  
Single Mutation ◽  
Uptake System ◽  
Ferric Reductase ◽  
Wild Type ◽  
Iron Starvation

The requirement for a reduction step in cellular iron uptake has been postulated, and the existence of plasma membrane ferric reductase activity has been described in both procaryotic and eucaryotic cells. In the yeast Saccharomyces cerevisiae, there is an externally directed reductase activity that is regulated by the concentration of iron in the growth medium; maximal activity is induced by iron starvation. We report here the isolation of a mutant of S. cerevisiae lacking the reductase activity. This mutant is deficient in the uptake of ferric iron and is extremely sensitive to iron deprivation. Genetic analysis of the mutant demonstrates that the reductase and ferric uptake deficiencies are due to a single mutation that we designate fre1-1. Both phenotypes cosegregate in meiosis, corevert with a frequency of 10(-7), and are complemented by a 3.5-kilobase fragment of genomic DNA from wild-type S. cerevisiae. This fragment contains FRE1, the wild-type allele of the mutant gene. The level of the gene transcript is regulated by iron in the same was as the reductase activity. The ferrous ion product of the reductase must traverse the plasma membrane. A high-affinity (Km = 5 microM) ferrous uptake system is present in both wild-type and mutant cells. Thus, iron uptake in S. cerevisiae is mediated by two plasma membrane components, a reductase and a ferrous transport system.

scholarly journals The Sinorhizobium meliloti ABC Transporter Cho Is Highly Specific for Choline and Expressed in Bacteroids from Medicago sativa Nodules

2004 ◽  
Vol 186 (18) ◽  
pp. 5988-5996 ◽  
Author(s):  
Laurence Dupont ◽  
Isabelle Garcia ◽  
Marie-Christine Poggi ◽  
Geneviève Alloing ◽  
Karine Mandon ◽  
...  
Keyword(s):  
Medicago Sativa ◽  
Abc Transporter ◽  
Sinorhizobium Meliloti ◽  
Lipid Membrane ◽  
Site Directed Mutagenesis ◽  
Choline Uptake ◽  
Uptake System ◽  
Choline Transport ◽  
High Affinity ◽  
Uptake Activity

ABSTRACT In Sinorhizobium meliloti, choline is the direct precursor of phosphatidylcholine, a major lipid membrane component in the Rhizobiaceae family, and glycine betaine, an important osmoprotectant. Moreover, choline is an efficient energy source which supports growth. Using a PCR strategy, we identified three chromosomal genes (choXWV) which encode components of an ABC transporter: ChoX (binding protein), ChoW (permease), and ChoV (ATPase). Whereas the best homology scores were obtained with components of betaine ProU-like systems, Cho is not involved in betaine transport. Site-directed mutagenesis of choX strongly reduced (60 to 75%) the choline uptake activity, and purification of ChoX, together with analysis of the ligand-binding specificity, showed that ChoX binds choline with a high affinity (K D , 2.7 μM) and acetylcholine with a low affinity (K D , 145 μM) but binds none of the betaines. Uptake competition experiments also revealed that ectoine, various betaines, and choline derivatives were not effective competitors for Cho-mediated choline transport. Thus, Cho is a highly specific high-affinity choline transporter. Choline transport activity and ChoX expression were induced by choline but not by salt stress. Western blotting experiments with antibodies raised against ChoX demonstrated the presence of ChoX in bacteroids isolated from nitrogen-fixing nodules obtained from Medicago sativa roots. The choX mutation did not have an effect on growth under standard conditions, and neither Nod nor Fix phenotypes were impaired in the mutant, suggesting that the remaining choline uptake system(s) still present in the mutant strain can compensate for the lack of Cho transporter.

scholarly journals Yeast protective response to arsenate involves the repression of the high affinity iron uptake system

2013 ◽  
Vol 1833 (5) ◽  
pp. 997-1005 ◽  
Author(s):  
Liliana Batista-Nascimento ◽  
Michel B. Toledano ◽  
Dennis J. Thiele ◽  
Claudina Rodrigues-Pousada
Keyword(s):  
Iron Uptake ◽  
Uptake System ◽  
Protective Response ◽  
High Affinity ◽  
Iron Uptake System

scholarly journals Dual Regulation of the Arabidopsis High-Affinity Root Iron Uptake System by Local and Long-Distance Signals

2003 ◽  
Vol 132 (2) ◽  
pp. 796-804 ◽  
Author(s):  
Grégory A. Vert ◽  
Jean-François Briat ◽  
Catherine Curie
Keyword(s):  
Iron Uptake ◽  
Uptake System ◽  
Long Distance ◽  
High Affinity ◽  
Iron Uptake System

The CaCTR1 gene is required for high-affinity iron uptake and is transcriptionally controlled by a copper-sensing transactivator encoded by CaMAC1

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2197-2208 ◽  
Author(s):  
Marcus E. Marvin ◽  
Robert P. Mason ◽  
Annette M. Cashmore
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Iron Uptake ◽  
Invasive Growth ◽  
Hostile Environment ◽  
Null Mutant ◽  
Copper Uptake ◽  
Similar System ◽  
Copper Transporter ◽  
High Affinity ◽  
Null Strain

The ability of Candida albicans to acquire iron from the hostile environment of the host is known to be necessary for virulence and appears to be achieved using a similar system to that described for Saccharomyces cerevisiae. In S. cerevisiae, high-affinity iron uptake is dependent upon the acquisition of copper. The authors have previously identified a C. albicans gene (CaCTR1) that encodes a copper transporter. Deletion of this gene results in a mutant strain that grows predominantly as pseudohyphae and displays aberrant morphology in low-copper conditions. This paper demonstrates that invasive growth by C. albicans is induced by low-copper conditions and that this is augmented in a Cactr1-null strain. It also shows that deletion of CaCTR1 results in defective iron uptake. In S. cerevisiae, genes that facilitate high-affinity copper uptake are controlled by a copper-sensing transactivator, ScMac1p. The authors have now identified a C. albicans gene (CaMAC1) that encodes a copper-sensing transactivator. A Camac1-null mutant displays phenotypes similar to those of a Cactr1-null mutant and has no detectable CaCTR1 transcripts in low-copper conditions. It is proposed that high-affinity copper uptake by C. albicans is necessary for reductive iron uptake and is transcriptionally controlled by CaMac1p in a similar manner to that in S. cerevisiae.

scholarly journals Ferrous Iron Uptake in Cryptococcus neoformans

1998 ◽  
Vol 66 (9) ◽  
pp. 4169-4175 ◽  
Author(s):  
Eric S. Jacobson ◽  
Asha Prasad Goodner ◽  
Karin J. Nyhus
Keyword(s):  
Cryptococcus Neoformans ◽  
Iron Uptake ◽  
Opportunistic Pathogen ◽  
Metabolic Energy ◽  
Yeast Cells ◽  
Ferric Reductase ◽  
High Affinity ◽  
Steep Rise ◽  
Uptake Pathway ◽  
Uptake Activity

ABSTRACT Previous studies have implicated ferric reduction in the iron uptake pathway of the opportunistic pathogen Cryptococcus neoformans. Here we studied iron uptake directly, using55Fe in the presence of reductants. Uptake was linear with respect to time and number of yeast cells. The plot of uptake versus concentration exhibited a steep rise up to about 1 μM, a plateau between 1 and 25 μM, and a second steep rise above 25 μM, consistent with high- and low-affinity uptake systems. AKm for high-affinity uptake was estimated to be 0.6 μM Fe(II); 1 μM was used for standardized uptake assays. At this concentration, the uptake rate was 110 ± 3 pmol/106 cells/h. Iron repletion (15 μM) and copper starvation drastically decreased high-affinity iron uptake. Incubation at 0°C or in the presence of 2 mM KCN abolished high-affinity iron uptake, suggesting that uptake requires metabolic energy. When exogenous reducing agents were not supplied and the culture was washed free of secreted reductants, uptake was reduced by 46%; the remaining uptake activity presumably was dependent upon the cell membrane ferric reductase. Further decreases in free Fe(II) levels achieved by trapping with bathophenanthroline disulfonate or reoxidizing with potassium nitrosodisulfonate reduced iron uptake very drastically, suggesting that it is the Fe(II) species which is transported by the high-affinity transporter. The uptake of Fe was stimulated two- to threefold by deferoxamine, but this increment could be abolished by copper starvation or inhibition of the ferric reductase by Pt, indicating that Fe solubilized by this molecule also entered the reductive iron uptake pathway.

scholarly journals Cloning, Expression, and Characterization of Cadmium and Manganese Uptake Genes from Lactobacillus plantarum

1999 ◽  
Vol 65 (11) ◽  
pp. 4746-4752 ◽  
Author(s):  
Zhiqi Hao ◽  
Shaolin Chen ◽  
David B. Wilson
Keyword(s):  
Lactobacillus Plantarum ◽  
Predicted Amino Acid Sequence ◽  
Uptake System ◽  
Gene Encoding ◽  
E Coli ◽  
High Affinity ◽  
Manganese Uptake ◽  
Uptake Activity ◽  
P Type ◽  
Energy Dependent

ABSTRACT An Mn2+ and Cd2+ uptake gene,mntA, was cloned from Lactobacillus plantarumATCC 14917 into Escherichia coli. Its expression conferred on E. coli cells increased Cd2+ sensitivity as well as energy-dependent Cd2+ uptake activity. Both transcription and translation of mntA were induced by Mn2+ starvation in L. plantarum, as indicated by reverse transcriptase PCR and immunoblotting. Two Cd2+uptake systems have been identified in L. plantarum: one is a high-affinity Mn2+ and Cd2+ uptake system that is expressed in Mn2+-starved cells, and the other is a nonsaturable Cd2+ uptake system that is expressed in Cd2+-sufficient cells (Z. Hao, H. R. Reiske, and D. B. Wilson, Appl. Environ. Microbiol. 65:592–99, 1999). MntA was not detected in an Mn2+-dependent mutant of L. plantarum which had lost high-affinity Mn2+ and Cd2+ uptake activity. The results suggest thatmntA is the gene encoding the high-affinity Mn2+ and Cd2+ transporter. On the basis of its predicted amino acid sequence, MntA belongs to the family of P-type cation-translocating ATPases. The topology and potential Mn2+- and Cd2+-binding sites of MntA are discussed. A second clone containing a low-affinity Cd2+transport system was also isolated.

Sign in / Sign up

Export Citation Format

Share Document