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.

The Candida albicans CTR1 gene encodes a functional copper transporter

Microbiology ◽  
2003 ◽  
Vol 149 (6) ◽  
pp. 1461-1474 ◽  
Author(s):  
Marcus E. Marvin ◽  
Peter H. Williams ◽  
Annette M. Cashmore
Keyword(s):  
Candida Albicans ◽  
Amino Acid ◽  
Protein Product ◽  
Uptake System ◽  
Copper Binding ◽  
Null Mutant ◽  
Copper Uptake ◽  
Similar System ◽  
Copper Transporter ◽  
High Affinity

Copper and iron uptake in Saccharomyces cerevisiae are linked through a high-affinity ferric/cupric-reductive uptake system. Evidence suggests that a similar system operates in Candida albicans. The authors have identified a C. albicans gene that is able to rescue a S. cerevisiae ctr1/ctr3-null mutant defective in high-affinity copper uptake. The 756 bp ORF, designated CaCTR1, encodes a 251 amino acid protein with a molecular mass of 27·8 kDa. Comparisons between the deduced amino acid sequence of the C. albicans Ctr1p and S. cerevisiae Ctr1p indicated that they share 39·6 % similarity and 33·0 % identity over their entire length. Within the predicted protein product of CaCTR1 there are putative transmembrane regions and sequences that resemble copper-binding motifs. The promoter region of CaCTR1 contains four sequences with significant identity to S. cerevisiae copper response elements. CaCTR1 is transcriptionally regulated in S. cerevisiae in response to copper availability by the copper-sensing transactivator Mac1p. Transcription of CaCTR1 in C. albicans is also regulated in a copper-responsive manner. This raises the possibility that CaCTR1 may be regulated in C. albicans by a Mac1p-like transactivator. A C. albicans ctr1-null mutant displays phenotypes consistent with the lack of copper uptake including growth defects in low-copper and low-iron conditions, a respiratory deficiency and sensitivity to oxidative stress. Furthermore, changes in morphology were observed in the C. albicans ctr1-null mutant. It is proposed that CaCTR1 facilitates transport of copper into the cell.

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 High-Affinity Copper Transport and Snq2 Export Permease of Saccharomyces cerevisiae Modulate Cytotoxicity of PR-10 from Theobroma cacao

2009 ◽  
Vol 22 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Cristina Pungartnik ◽  
Aline Clara da Silva ◽  
Sarah Alves de Melo ◽  
Karina Peres Gramacho ◽  
Júlio Cézar de Mattos Cascardo ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Theobroma Cacao ◽  
Single Gene ◽  
Copper Transport ◽  
Amino Acid Sequences ◽  
Yeast Cells ◽  
Antioxidant Defenses ◽  
Copper Transporter ◽  
High Affinity ◽  
Yeast Mutants

A pathogenesis-related (PR) protein from Theobroma cacao (TcPR-10) was identified from a cacao–Moniliophthora perniciosa interaction cDNA library. Nucleotide and amino acid sequences showed homology with other PR-10 proteins having P loop motif and Betv1 domain. Recombinant TcPR-10 showed in vitro and in vivo ribonuclease activity, and antifungal activity against the basidiomycete cacao pathogen M. perniciosa and the yeast Saccharomyces cerevisiae. Fluorescein isothiocyanate-labeled TcPR-10 was internalized by M. perniciosa hyphae and S. cerevisiae cells and inhibited growth of both fungi. Energy and temperature-dependent internalization of the TcPR-10 suggested an active importation into the fungal cells. Chronical exposure to TcPR-10 of 29 yeast mutants with single gene defects in DNA repair, general membrane transport, metal transport, and antioxidant defenses was tested. Two yeast mutants were hyperresistant compared with their respective isogenic wild type: ctr3Δ mutant, lacking the high-affinity plasma membrane copper transporter and mac1Δ, the copper-sensing transcription factor involved in regulation of high-affinity copper transport. Acute exposure of exponentially growing yeast cells revealed that TcPR-10 resistance is also enhanced in the Snq2 export permease-lacking mutant which has reduced intracellular presence of TcPR-10.

scholarly journals The Fe(II) permease Fet4p functions as a low affinity copper transporter and supports normal copper trafficking in Saccharomyces cerevisiae

2000 ◽  
Vol 351 (2) ◽  
pp. 477-484 ◽  
Author(s):  
Richard HASSETT ◽  
David R. DIX ◽  
David J. EIDE ◽  
Daniel J. KOSMAN
Keyword(s):  
Metal Ion ◽  
Competitive Inhibitor ◽  
Yeast Cells ◽  
Amino Acid Residues ◽  
Copper Uptake ◽  
Copper Transporter ◽  
Copper Trafficking ◽  
High Affinity ◽  
Uptake Pathway ◽  
Mutant Forms

The plasma-membrane of Saccharomycescerevisiae contains high affinity permeases for Cu(I) and Fe(II). A low affinity Fe(II) permease has also been identified, designated Fet4p. A corresponding low affinity copper permease has not been characterized, although yeast cells that lack high affinity copper uptake do accumulate this metal ion. We demonstrate in the present study that Fet4p can function as a low affinity copper permease. Copper is a non-competitive inhibitor of 55Fe uptake through Fet4p (Ki = 22µM). Fet4p-dependent 67Cu uptake was kinetically characterized, with Km and Vmax values of 35µM and 8pmol of copper/min per 106 cells respectively. A fet4-containing strain exhibited no saturable, low affinity copper uptake indicating that this uptake was attributable to Fet4p. Mutant forms of Fet4p that exhibited decreased efficiency in 55/59Fe uptake were similarly compromised in 67Cu uptake, indicating that similar amino acid residues in Fet4p contribute to both uptake processes. The copper taken into the cell by Fet4p was metabolized similarly to the copper taken into the cell by the high affinity permease, Ctr1p. This was shown by the Fet4p-dependence of copper activation of Fet3p, the copper oxidase that supports high affinity iron uptake in yeast. Also, copper-transported by Fet4p down-regulated the copper sensitive transcription factor, Mac1p. Whether supplied by Ctr1p or by Fet4p, an intracellular copper concentration of approx. 10µM caused a 50% reduction in the transcriptional activity of Mac1p. The data suggest that the initial trafficking of newly arrived copper in the yeast cell is independent of the copper uptake pathway involved, and that this copper may be targeted first to a presumably small ‘holding’pool prior to its partitioning within the cell.

DMT1, a physiologically relevant apical Cu1+transporter of intestinal cells

2003 ◽  
Vol 284 (6) ◽  
pp. C1525-C1530 ◽  
Author(s):  
Miguel Arredondo ◽  
Patricia Muñoz ◽  
Casilda V. Mura ◽  
Marco T. Núñez
Keyword(s):  
Iron Content ◽  
Antisense Oligonucleotide ◽  
Iron Uptake ◽  
Potential Role ◽  
Intestinal Cells ◽  
Copper Uptake ◽  
High Iron Content ◽  
Copper Transporter ◽  
Molecular Components

Despite important advances in the understanding of copper secretion and excretion, the molecular components of intestinal copper absorption remain a mystery. DMT1, also known as Nramp2 and DCT1, is the transporter responsible for intestinal iron uptake. Electrophysiological evidence suggests that DMT1 can also be a copper transporter. Thus we examined the potential role of DMT1 as a copper transporter in intestinal Caco-2 cells. Treatment of cells with a DMT1 antisense oligonucleotide resulted in 80 and 48% inhibition of iron and copper uptake, respectively. Cells incorporated considerable amounts of copper as Cu1+, whereas Cu2+ transport was about 10-fold lower. Cu1+inhibited apical Fe2+ transport. Fe2+, but not Fe3+, effectively inhibited Cu1+ uptake. The iron content of the cells influenced both copper and iron uptake. Cells with low iron content transported fourfold more iron and threefold more copper than cells with high iron content. These results demonstrate that DMT1 is a physiologically relevant Cu1+ transporter in intestinal cells, indicating that intestinal absorption of copper and iron are intertwined.

scholarly journals ROX1 encodes a heme-induced repression factor regulating ANB1 and CYC7 of Saccharomyces cerevisiae.

1988 ◽  
Vol 8 (11) ◽  
pp. 4651-4658 ◽  
Author(s):  
C V Lowry ◽  
R S Zitomer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Constitutive Expression ◽  
Null Mutant ◽  
Aerobic Growth ◽  
The Family ◽  
Negative Effect ◽  
Induced Genes ◽  
Cloned Gene ◽  
Null Strain

The ROX1 gene encodes a product implicated in the regulation of heme-repressed and heme-induced genes in Saccharomyces cerevisiae. The gene has been cloned and shown to code for a 1.4-kilobase transcript. The cloned gene was used to construct a null mutant to determine the role of ROX1 in regulating the expression of several heme-regulated genes. Constitutive expression of ANB1 (a heme-repressed gene) was observed in the null strain, indicating that ROX1 codes for a repressor or a facilitator of repression. Enhancement of expression of CYC7 in the null strain indicated that the ROX1 factor is required for repression of CYC7 to its normal low level of expression, consistent with evidence that CYC7 has a hybrid heme-induced, heme-repressed regulatory mechanism. The null mutation had only a slight negative effect on expression of the heme-induced genes CYC1 and tr-1 (a heme-induced homolog of ANB1), suggesting that the ROX1 factor is not directly involved in their regulation despite the existence of an unusual rox1 mutation (rox1-a1) causing constitutive expression of this group. The respiratory competence of the null mutant indicates that ROX1 is not a respiratory factor. ROX1 expression was found to be induced by heme, indicating that the heme repression of ANB1 and its family is the result of a cascade in which heme induces a repression factor which keeps the family of heme-repressed genes inactive during aerobic growth. The rox1-a1 allele had earlier been shown to cause constitutive expression of the family of heme-induced respiratory genes. This allele was found to cause constitutive expression of the ROX1 transcript itself, indicating that ROX1 is in the major heme-induced regulon.

scholarly journals The Conformational Plasticity of the Selectivity Filter Methionines Controls the In-Cell Cu(I) Uptake through the CTR1 transporter

2021 ◽  
Author(s):  
Pavel Janoš ◽  
Jana Aupič ◽  
Sharon Ruthstein ◽  
Alessandra Magistrato
Keyword(s):  
Cellular Uptake ◽  
Selectivity Filter ◽  
Copper Uptake ◽  
Cellular Functions ◽  
Copper Transporter ◽  
High Affinity ◽  
Windows Of Opportunity ◽  
Conformational Plasticity ◽  
Copper Transporter 1 ◽  
Autoregulatory Mechanism

Copper is a trace element vital to many cellular functions. Yet its abnormal levels are toxic to cells, provoking a variety of severe diseases. The high affinity Copper Transporter 1 (CTR1), being the main in-cell copper (Cu(I)) entry route, tightly regulates its cellular uptake via a still elusive mechanism. Here, all-atoms simulations unlock the molecular terms of Cu(I) transport in eukaryotes disclosing that the two Methionine triads, forming the selectivity filter, play an unprecedented dual role both enabling selective Cu(I) transport and regulating its uptake-rate thanks to an intimate coupling between the conformational plasticity of their bulky side chains and the number of bound Cu(I) ions. Namely, the Met residues act as a gate reducing the Cu(I) import-rate when two ions simultaneously bind to CTR1. This may represent an elegant autoregulatory mechanism through which CTR1 protects the cells from excessively high, and hence toxic, in-cell Cu(I) levels. Overall, these outcomes resolve fundamental questions in CTR1 biology and open new windows of opportunity to tackle diseases associated with an imbalanced copper uptake.

ROX1 encodes a heme-induced repression factor regulating ANB1 and CYC7 of Saccharomyces cerevisiae

1988 ◽  
Vol 8 (11) ◽  
pp. 4651-4658
Author(s):  
C V Lowry ◽  
R S Zitomer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Constitutive Expression ◽  
Null Mutant ◽  
Aerobic Growth ◽  
The Family ◽  
Negative Effect ◽  
Induced Genes ◽  
Cloned Gene ◽  
Null Strain

The ROX1 gene encodes a product implicated in the regulation of heme-repressed and heme-induced genes in Saccharomyces cerevisiae. The gene has been cloned and shown to code for a 1.4-kilobase transcript. The cloned gene was used to construct a null mutant to determine the role of ROX1 in regulating the expression of several heme-regulated genes. Constitutive expression of ANB1 (a heme-repressed gene) was observed in the null strain, indicating that ROX1 codes for a repressor or a facilitator of repression. Enhancement of expression of CYC7 in the null strain indicated that the ROX1 factor is required for repression of CYC7 to its normal low level of expression, consistent with evidence that CYC7 has a hybrid heme-induced, heme-repressed regulatory mechanism. The null mutation had only a slight negative effect on expression of the heme-induced genes CYC1 and tr-1 (a heme-induced homolog of ANB1), suggesting that the ROX1 factor is not directly involved in their regulation despite the existence of an unusual rox1 mutation (rox1-a1) causing constitutive expression of this group. The respiratory competence of the null mutant indicates that ROX1 is not a respiratory factor. ROX1 expression was found to be induced by heme, indicating that the heme repression of ANB1 and its family is the result of a cascade in which heme induces a repression factor which keeps the family of heme-repressed genes inactive during aerobic growth. The rox1-a1 allele had earlier been shown to cause constitutive expression of the family of heme-induced respiratory genes. This allele was found to cause constitutive expression of the ROX1 transcript itself, indicating that ROX1 is in the major heme-induced regulon.

scholarly journals Mammalian copper homeostasis requires retromer-dependent recycling of the high-affinity copper transporter 1

2020 ◽  
Vol 133 (16) ◽  
pp. jcs249201 ◽  
Author(s):  
Rachel Curnock ◽  
Peter J. Cullen
Keyword(s):  
Cell Surface ◽  
Nutrient Balance ◽  
Copper Homeostasis ◽  
Copper Exposure ◽  
Copper Uptake ◽  
Copper Transporter ◽  
High Affinity ◽  
Cellular Copper ◽  
Copper Transporter 1 ◽  
Toxicity Effects

ABSTRACTThe concentration of essential micronutrients, such as copper (used here to describe both Cu+ and Cu2+), within the cell is tightly regulated to avoid their adverse deficiency and toxicity effects. Retromer-mediated sorting and recycling of nutrient transporters within the endo-lysosomal network is an essential process in regulating nutrient balance. Cellular copper homeostasis is regulated primarily by two transporters: the copper influx transporter copper transporter 1 (CTR1; also known as SLC31A1), which controls the uptake of copper, and the copper-extruding ATPase ATP7A, a recognised retromer cargo. Here, we show that in response to fluctuating extracellular copper, retromer controls the delivery of CTR1 to the cell surface. Following copper exposure, CTR1 is endocytosed to prevent excessive copper uptake. We reveal that internalised CTR1 localises on retromer-positive endosomes and, in response to decreased extracellular copper, retromer controls the recycling of CTR1 back to the cell surface to maintain copper homeostasis. In addition to copper, CTR1 plays a central role in the trafficking of platinum. The efficacy of platinum-based cancer drugs has been correlated with CTR1 expression. Consistent with this, we demonstrate that retromer-deficient cells show reduced sensitivity to the platinum-based drug cisplatin.

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