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Baruah D, Tamuli R. The cell functions of phospholipase C-1, Ca 2+/H + exchanger-1, and secretory phospholipase A 2 in tolerance to stress conditions and cellulose degradation in Neurospora crassa. Arch Microbiol 2023; 205:327. [PMID: 37676310 DOI: 10.1007/s00203-023-03662-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 08/13/2023] [Accepted: 08/17/2023] [Indexed: 09/08/2023]
Abstract
We investigated the cell functions of the Ca2+ signaling genes phospholipase C-1 (plc-1), Ca2+/H+ exchanger (cpe-1), and secretory phospholipase A2 (splA2) for stress responses and cellulose utilization in Neurospora crassa. The Δplc-1, Δcpe-1, and ΔsplA2 mutants displayed increased sensitivity to the alkaline pH and reduced survival during induced thermotolerance. The ΔsplA2 mutant also exhibited hypersensitivity to the DTT-induced endoplasmic reticulum (ER) stress, increased microcrystalline cellulose utilization, increased protein secretion, and glucose accumulation in the culture supernatants. Moreover, the ΔsplA2 mutant could not grow on microcrystalline cellulose during ER stress. Furthermore, plc-1, cpe-1, and splA2 synthetically regulate the acquisition of thermotolerance induced by heat shock, responses to alkaline pH and ER stress, and utilization of cellulose and other alternate carbon sources in N. crassa. In addition, expression of the alkaline pH regulator, pac-3, and heat shock proteins, hsp60, and hsp80 was reduced in the Δplc-1, Δcpe-1, and ΔsplA2 single and double mutants. The expression of the unfolded protein response (UPR) markers grp-78 and pdi-1 was also significantly reduced in the mutants showing growth defect during ER stress. The increased cellulolytic activities of the ΔsplA2 and Δcpe-1; ΔsplA2 mutants were due to increased cbh-1, cbh-2, and endo-2 expression in N. crassa. Therefore, plc-1, cpe-1, and splA2 are involved in stress responses and cellulose utilization in N. crassa.
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Affiliation(s)
- Darshana Baruah
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781 039, India
| | - Ranjan Tamuli
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781 039, India.
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Garcia AWA, Kinskovski UP, Diehl C, Reuwsaat JCV, Motta de Souza H, Pinto HB, Trentin DDS, de Oliveira HC, Rodrigues ML, Becker EM, Kmetzsch L, Vainstein MH, Staats CC. Participation of Zip3, a ZIP domain-containing protein, in stress response and virulence in Cryptococcus gattii. Fungal Genet Biol 2020; 144:103438. [PMID: 32738289 DOI: 10.1016/j.fgb.2020.103438] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 07/21/2020] [Accepted: 07/22/2020] [Indexed: 12/16/2022]
Abstract
Cryptococcus gattii is an etiologic agent of cryptococcosis, a potentially fatal disease that affects humans and animals. The successful infection of mammalian hosts by cryptococcal cells relies on their ability to infect and survive in macrophages. Such phagocytic cells present a hostile environment to intracellular pathogens via the production of reactive nitrogen and oxygen species, as well as low pH and reduced nutrient bioavailability. To overcome the low-metal environment found during infection, fungal pathogens express high-affinity transporters, including members of the ZIP family. Previously, we determined that functional zinc uptake driven by Zip1 and Zip2 is necessary for full C.gattiivirulence. Here, we characterized the ZIP3 gene of C. gattii, an ortholog of the Saccharomyces cerevisiae ATX2, which codes a manganese transporter localized to the membrane of the Golgi apparatus. Cryptococcal cells lacking Zip3 were tolerant to toxic concentrations of manganese and had imbalanced expression of intracellular metal transporters, such as the vacuolar Pmc1 and Vcx1, as well as the Golgi Pmr1. Moreover, null mutants of the ZIP3 gene displayed higher sensitivity to reactive oxygen species (ROS) and substantial alteration in the expression of ROS-detoxifying enzyme-coding genes. In line with these phenotypes, cryptococcal cells displayed decreased virulence in a non-vertebrate model of cryptococcosis. Furthermore, we found that the ZIP3 null mutant strain displayed decreased melanization and secretion of the major capsular component glucuronoxylomannan, as well as an altered extracellular vesicle dimensions profile. Collectively, our data suggest that Zip3 activity impacts the physiology, and consequently, several virulence traits of C. gattii.
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Affiliation(s)
| | - Uriel Perin Kinskovski
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Camila Diehl
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | - Heryk Motta de Souza
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Helber Barboza Pinto
- Departamento de Ciências Básicas da Saúde, Programa de Pós-Graduação em Biociências, Universidade Federal de Ciências da Saúde de Porto Alegre
| | - Danielle da Silva Trentin
- Departamento de Ciências Básicas da Saúde, Programa de Pós-Graduação em Biociências, Universidade Federal de Ciências da Saúde de Porto Alegre
| | | | - Marcio L Rodrigues
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (Fiocruz), Curitiba, Brazil; Instituto de Microbiologia da Universidade Federal do Rio de Janeiro, Brazil
| | - Emilene Mendes Becker
- Instituto de Química, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Livia Kmetzsch
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Marilene Henning Vainstein
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Charley Christian Staats
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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3
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Ibuot A, Dean AP, Pittman JK. Multi-genomic analysis of the cation diffusion facilitator transporters from algae. Metallomics 2020; 12:617-630. [PMID: 32195517 DOI: 10.1039/d0mt00009d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Metal transport processes are relatively poorly understood in algae in comparison to higher plants and other eukaryotes. A screen of genomes from 33 taxonomically diverse algal species was conducted to identify members of the Cation Diffusion Facilitator (CDF) family of metal ion transporter. All algal genomes contained at least one CDF gene with four species having >10 CDF genes (median of 5 genes per genome), further confirming that this is a ubiquitous gene family. Phylogenetic analysis suggested a CDF gene organisation of five groups, which includes Zn-CDF, Fe/Zn-CDF and Mn-CDF groups, consistent with previous phylogenetic analyses, and two functionally undefined groups. One of these undefined groups was algal specific although excluded chlorophyte and rhodophyte sequences. The majority of sequences (22 out of 26 sequences) from this group had a putative ion binding site motif within transmembrane domain 2 and 5 that was distinct from other CDF proteins, such that alanine or serine replaced the conserved histidine residue. The phylogenetic grouping was supported by sequence cluster analysis. Yeast heterologous expression of CDF proteins from Chlamydomonas reinhardtii indicated Zn2+ and Co2+ transport function by CrMTP1, and Mn2+ transport function by CrMTP2, CrMTP3 and CrMTP4, which validated the phylogenetic prediction. However, the Mn-CDF protein CrMTP3 was also able to provide zinc and cobalt tolerance to the Zn- and Co-sensitive zrc1 cot1 yeast strain. There is wide diversity of CDF transporters within the algae lineage, and some of these genes may be attractive targets for future applications of metal content engineering in plants or microorganisms.
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Affiliation(s)
- Aniefon Ibuot
- Department of Science Technology, Akwa Ibom State Polytechnic, P.M.B. 1200 Ikot Ekpene, Ikot Osurua, Akwa Ibom State, Nigeria
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Li Y, Zhang Y, Lu L. Calcium signaling pathway is involved in non-CYP51 azole resistance in Aspergillus fumigatus. Med Mycol 2019; 57:S233-S238. [PMID: 30816964 DOI: 10.1093/mmy/myy075] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/05/2018] [Accepted: 09/03/2018] [Indexed: 12/20/2022] Open
Abstract
The opportunistic fungal pathogen Aspergillus fumigatus, which is one of the primary airborne ascomycete pathogens and allergens worldwide, causes invasive fungal infections, which have high morbidity and mortality rates among immunosuppressed patients. The abuse of azole antifungals results in serious drug resistance in clinical therapy. Thus, a thorough understanding of the azole drug resistance mechanism and screening of antifungal agents with a novel mode of action and new drug targets are required to fight against drug resistance. Current studies suggest that there are three major azole resistance mechanisms in fungal pathogens, including changes of the drug target Cyp51, activation of drug efflux pumps and induction of cellular stress responses. Fungi must adapt to a variety of external environmental stressors to survive. These obstacles include stress to the plasma membrane after azole antifungal treatments, high temperature, pH variation, and oxidative stress. As a filamentous fungus, A. fumigatus has evolved numerous signal-transduction systems to sense and respond to azole stresses to survive and proliferate in harsh environmental conditions. Among these signal-transduction systems, the Ca2+ signaling pathway is one of the most important response systems, which has been verified to be involved in stress adaptation. In this review, we have summarized how the components of the calcium-signaling pathway and their interaction network are involved in azole stress response in A. fumigatus.
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Affiliation(s)
- Yeqi Li
- Jiangsu Key laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Yuanwei Zhang
- Jiangsu Key laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Ling Lu
- Jiangsu Key laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
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Migocka M, Maciaszczyk-Dziubinska E, Małas K, Posyniak E, Garbiec A. Metal tolerance protein MTP6 affects mitochondrial iron and manganese homeostasis in cucumber. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:285-300. [PMID: 30304441 PMCID: PMC6305187 DOI: 10.1093/jxb/ery342] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/24/2018] [Indexed: 05/24/2023]
Abstract
Members of the cation diffusion facilitator (CDF) family have been identified in all kingdoms of life. They have been divided into three subgroups, namely Zn-CDF, Fe/Zn-CDF, and Mn-CDF, based on their putative specificity to transported metal ions. The plant metal tolerance protein 6 (MTP6) proteins fall into the Fe/Zn-CDF subgroup; however, their function in iron/zinc transport has not yet been confirmed. Here, we characterized the MTP6 protein from cucumber, Cucumis sativus. When expressed in yeast and in protoplasts isolated from Arabidopsis cells, CsMTP6 localized in mitochondria and contributed to the efflux of Fe and Mn from these organelles. Immunolocalization of CsMTP6 in cucumber membranes confirmed this association with mitochondria. Root expression and protein levels of CsMTP6 were significantly up-regulated in conditions of Fe deficiency and excess, but were not affected by Mn availability. These results indicate that MTP6 proteins contribute to the distribution of Fe and Mn between the cytosol and mitochondria of plant cells, and are regulated by Fe to maintain mitochondrial and cytosolic iron homeostasis under varying conditions of Fe availability.
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Affiliation(s)
- Magdalena Migocka
- University of Wroclaw, Institute of Experimental Biology, Department of Plant Molecular Physiology, Kanonia, Wroclaw, Poland
| | - Ewa Maciaszczyk-Dziubinska
- University of Wroclaw, Institute of Experimental Biology, Department of Genetics and Cell Physiology, Kanonia, Wroclaw, Poland
| | - Karolina Małas
- University of Wroclaw, Institute of Experimental Biology, Department of Plant Molecular Physiology, Kanonia, Wroclaw, Poland
| | - Ewelina Posyniak
- University of Wroclaw, Institute of Experimental Biology, Department of Animal Developmental Biology, Sienkiewicza, Wroclaw, Poland
| | - Arnold Garbiec
- University of Wroclaw, Institute of Experimental Biology, Department of Animal Developmental Biology, Sienkiewicza, Wroclaw, Poland
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Ghanegolmohammadi F, Yoshida M, Ohnuki S, Sukegawa Y, Okada H, Obara K, Kihara A, Suzuki K, Kojima T, Yachie N, Hirata D, Ohya Y. Systematic analysis of Ca 2+ homeostasis in Saccharomyces cerevisiae based on chemical-genetic interaction profiles. Mol Biol Cell 2017; 28:3415-3427. [PMID: 28566553 PMCID: PMC5687040 DOI: 10.1091/mbc.e17-04-0216] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 12/20/2022] Open
Abstract
We investigated the global landscape of Ca2+ homeostasis in budding yeast based on high-dimensional chemical-genetic interaction profiles. The morphological responses of 62 Ca2+-sensitive (cls) mutants were quantitatively analyzed with the image processing program CalMorph after exposure to a high concentration of Ca2+ After a generalized linear model was applied, an analysis of covariance model was used to detect significant Ca2+-cls interactions. We found that high-dimensional, morphological Ca2+-cls interactions were mixed with positive (86%) and negative (14%) chemical-genetic interactions, whereas one-dimensional fitness Ca2+-cls interactions were all negative in principle. Clustering analysis with the interaction profiles revealed nine distinct gene groups, six of which were functionally associated. In addition, characterization of Ca2+-cls interactions revealed that morphology-based negative interactions are unique signatures of sensitized cellular processes and pathways. Principal component analysis was used to discriminate between suppression and enhancement of the Ca2+-sensitive phenotypes triggered by inactivation of calcineurin, a Ca2+-dependent phosphatase. Finally, similarity of the interaction profiles was used to reveal a connected network among the Ca2+ homeostasis units acting in different cellular compartments. Our analyses of high-dimensional chemical-genetic interaction profiles provide novel insights into the intracellular network of yeast Ca2+ homeostasis.
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Affiliation(s)
| | - Mitsunori Yoshida
- Department of Integrated Biosciences, University of Tokyo, Kashiwa 277-8562, Japan
| | - Shinsuke Ohnuki
- Department of Integrated Biosciences, University of Tokyo, Kashiwa 277-8562, Japan
| | - Yuko Sukegawa
- Department of Integrated Biosciences, University of Tokyo, Kashiwa 277-8562, Japan
- AIST-UTokyo Advanced Operand-Measurement Technology Open Innovation Laboratory, Kashiwa 277-0882, Japan
| | - Hiroki Okada
- Department of Integrated Biosciences, University of Tokyo, Kashiwa 277-8562, Japan
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058
| | - Keisuke Obara
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Akio Kihara
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Kuninori Suzuki
- Department of Integrated Biosciences, University of Tokyo, Kashiwa 277-8562, Japan
- Bioimaging Center, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa 277-8562, Japan
| | - Tetsuya Kojima
- Department of Integrated Biosciences, University of Tokyo, Kashiwa 277-8562, Japan
| | - Nozomu Yachie
- Synthetic Biology Division, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan
- PRESTO, Japan Science and Technology Agency, Tokyo 102-0076, Japan
| | - Dai Hirata
- Research and Development Department, Asahi Sake Brewing Co., Nagaoka 949-5494, Japan
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Yoshikazu Ohya
- Department of Integrated Biosciences, University of Tokyo, Kashiwa 277-8562, Japan
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Metal bioremediation by CrMTP4 over-expressing Chlamydomonas reinhardtii in comparison to natural wastewater-tolerant microalgae strains. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.03.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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8
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Chow EWL, Clancey SA, Billmyre RB, Averette AF, Granek JA, Mieczkowski P, Cardenas ME, Heitman J. Elucidation of the calcineurin-Crz1 stress response transcriptional network in the human fungal pathogen Cryptococcus neoformans. PLoS Genet 2017; 13:e1006667. [PMID: 28376087 PMCID: PMC5380312 DOI: 10.1371/journal.pgen.1006667] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 03/01/2017] [Indexed: 12/02/2022] Open
Abstract
Calcineurin is a highly conserved Ca2+/calmodulin-dependent serine/threonine-specific protein phosphatase that orchestrates cellular Ca2+ signaling responses. In Cryptococcus neoformans, calcineurin is activated by multiple stresses including high temperature, and is essential for stress adaptation and virulence. The transcription factor Crz1 is a major calcineurin effector in Saccharomyces cerevisiae and other fungi. Calcineurin dephosphorylates Crz1, thereby enabling Crz1 nuclear translocation and transcription of target genes. Here we show that loss of Crz1 confers phenotypes intermediate between wild-type and calcineurin mutants, and demonstrate that deletion of the calcineurin docking domain results in the inability of Crz1 to translocate into the nucleus under thermal stress. RNA-sequencing revealed 102 genes that are regulated in a calcineurin-Crz1-dependent manner at 37°C. The majority of genes were down-regulated in cna1Δ and crz1Δ mutants, indicating these genes are normally activated by the calcineurin-Crz1 pathway at high temperature. About 58% of calcineurin-Crz1 target genes have unknown functions, while genes with known or predicted functions are involved in cell wall remodeling, calcium transport, and pheromone production. We identified three calcineurin-dependent response element motifs within the promoter regions of calcineurin-Crz1 target genes, and show that Crz1 binding to target gene promoters is increased upon thermal stress in a calcineurin-dependent fashion. Additionally, we found a large set of genes independently regulated by calcineurin, and Crz1 regulates 59 genes independently of calcineurin. Given the intermediate crz1Δ mutant phenotype, and our recent evidence for a calcineurin regulatory network impacting mRNA in P-bodies and stress granules independently of Crz1, calcineurin likely acts on factors beyond Crz1 that govern mRNA expression/stability to operate a branched transcriptional/post-transcriptional stress response network necessary for fungal virulence. Taken together, our findings reveal the core calcineurin-Crz1 stress response cascade is maintained from ascomycetes to a pathogenic basidiomycete fungus, but its output in C. neoformans appears to be adapted to promote fungal virulence. The ubquitiously conserved serine/threonine-specific protein phosphatase calcineurin is crucial for virulence of several opportunistic human fungal pathogens including Candida albicans, Aspergillus fumigatus, and Cryptococcus neoformans. We show that Crz1 acts downstream of calcineurin, to 1) govern expression of genes involved in cell wall integrity, and calcium and small molecule transport, and 2) contribute to stress survival and virulence of C. neoformans. Our studies reveal that calcineurin also controls mRNA expression levels of other genes independently of Crz1. We propose that calcineurin operates in a branched signal transduction cascade controlling targets at both the transcriptional and post-transcriptional levels.
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Affiliation(s)
- Eve W. L. Chow
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Shelly A. Clancey
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - R. Blake Billmyre
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Anna Floyd Averette
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Joshua A. Granek
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Center for the Genomics of Microbial Systems, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Piotr Mieczkowski
- High-Throughput Sequencing Facility, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Maria E. Cardenas
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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Ansari MA, Fatima Z, Hameed S. Anticandidal Effect and Mechanisms of Monoterpenoid, Perillyl Alcohol against Candida albicans. PLoS One 2016; 11:e0162465. [PMID: 27627759 PMCID: PMC5023166 DOI: 10.1371/journal.pone.0162465] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/23/2016] [Indexed: 12/17/2022] Open
Abstract
This study explored the antifungal potential of perillyl alcohol (PA), a natural monoterpene alcohol, against most prevalent human fungal pathogen C. albicans, its clinical isolates and four non-albicans species of Candida. To resolve the potential mechanisms, we used whole genome transcriptome analyses of PA treated Candida cells to examine the affected cellular circuitry of this pathogen. The transcriptome data revealed a link between calcineurin signaling and PA as among the several categories of PA responsive genes the down regulation of calcineurin signaling gene CNB1 was noteworthy which was also confirmed by both molecular docking and susceptibility assays. We observed that PA treated Candida phenocopied compromised calcineurin pathway stress responses and turned sensitive to alkaline pH, ionic, membrane, salinity, endoplasmic reticulum and serum stresses. Indispensability of functional calcineurin was further confirmed as calcineurin mutant was hypersensitive to PA while constitutively expressed calcineurin strain remained resistant. We explored that PA leads to perturbed membrane integrity as depicted through depleted ergosterol levels and disrupted pH homeostasis. Moreover, PA caused cell wall damage which was evident from hypersensitivity against cell wall perturbing agents (congo red, calcoflour white), SEM and enhanced rate of cell sedimentation. Furthermore, PA inhibited potential virulence traits including morphological transition, biofilm formation and displayed diminished capacity to adhere both to the polystyrene surface and buccal epithelial cells. The study also revealed that PA leads to cell cycle arrest and mitochondrial dysfunction in C. albicans. Together, the present study provides enough evidence for further work on PA so that better strategies could be employed to treat Candida infections.
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Affiliation(s)
- Moiz A. Ansari
- Amity Institute of Biotechnology, Amity University Haryana, Gurgaon (Manesar)-122413, India
| | - Zeeshan Fatima
- Amity Institute of Biotechnology, Amity University Haryana, Gurgaon (Manesar)-122413, India
- * E-mail: (SH); (ZF)
| | - Saif Hameed
- Amity Institute of Biotechnology, Amity University Haryana, Gurgaon (Manesar)-122413, India
- * E-mail: (SH); (ZF)
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Calcineurin and Calcium Channel CchA Coordinate the Salt Stress Response by Regulating Cytoplasmic Ca2+ Homeostasis in Aspergillus nidulans. Appl Environ Microbiol 2016; 82:3420-3430. [PMID: 27037124 DOI: 10.1128/aem.00330-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/28/2016] [Indexed: 11/20/2022] Open
Abstract
The eukaryotic calcium/calmodulin-dependent protein phosphatase calcineurin is crucial for the environmental adaption of fungi. However, the mechanism of coordinate regulation of the response to salt stress by calcineurin and the high-affinity calcium channel CchA in fungi is not well understood. Here we show that the deletion of cchA suppresses the hyphal growth defects caused by the loss of calcineurin under salt stress in Aspergillus nidulans Additionally, the hypersensitivity of the ΔcnaA strain to extracellular calcium and cell-wall-damaging agents can be suppressed by cchA deletion. Using the calcium-sensitive photoprotein aequorin to monitor the cytoplasmic Ca(2+) concentration ([Ca(2+)]c) in living cells, we found that calcineurin negatively regulates CchA on calcium uptake in response to external calcium in normally cultured cells. However, in salt-stress-pretreated cells, loss of either cnaA or cchA significantly decreased the [Ca(2+)]c, but a deficiency in both cnaA and cchA switches the [Ca(2+)]c to the reference strain level, indicating that calcineurin and CchA synergistically coordinate calcium influx under salt stress. Moreover, real-time PCR results showed that the dysfunction of cchA in the ΔcnaA strain dramatically restored the expression of enaA (a major determinant for sodium detoxification), which was abolished in the ΔcnaA strain under salt stress. These results suggest that double deficiencies of cnaA and cchA could bypass the requirement of calcineurin to induce enaA expression under salt stress. Finally, YvcA, a member of the transient receptor potential channel (TRPC) protein family of vacuolar Ca(2+) channels, was proven to compensate for calcineurin-CchA in fungal salt stress adaption.IMPORTANCE The feedback inhibition relationship between calcineurin and the calcium channel Cch1/Mid1 has been well recognized from yeast. Interestingly, our previous study (S. Wang et al., PLoS One 7:e46564, 2012, http://dx.doi.org/10.1371/journal.pone.0046564) showed that the deletion of cchA could suppress the hyphal growth defects caused by the loss of calcineurin under salt stress in Aspergillus nidulans In this study, our findings suggest that fungi are able to develop a unique mechanism for adapting to environmental salt stress. Compared to cells cultured normally, the NaCl-pretreated cells had a remarkable increase in transient [Ca(2+)]c Furthermore, we show that calcineurin and CchA are required to modulate cellular calcium levels and synergistically coordinate calcium influx under salt stress. Finally, YvcA, a member of of the TRPC family of vacuolar Ca(2+) channels, was proven to compensate for calcineurin-CchA in fungal salt stress adaption. The findings in this study provide insights into the complex regulatory links between calcineurin and CchA to maintain cytoplasmic Ca(2+) homeostasis in response to different environments.
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11
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Zhao Y, Xu H, Zhang Y, Jiang L. Vcx1-D1 (M383I), the Vcx1 mutant with a calcineurin-independent vacuolar Ca(2+)/H(+) exchanger activity, confers calcineurin-independent Mn(2+) tolerance in Saccharomyces cerevisiae. Can J Microbiol 2016; 62:475-84. [PMID: 27100389 DOI: 10.1139/cjm-2015-0595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Vcx1-M1 mutant is known to confer calcineurin-dependent Mn(2+) tolerance in budding yeast. Here, we demonstrate that another Vcx1 mutant, Vcx1-D1 with calcineurin-independent vacuolar Ca(2+)/H(+) exchanger activity, confers calcineurin-independent Mn(2+) tolerance. Unlike Vcx1-M1, the Mn(2+) tolerance conferred by Vcx1-D1 is dependent on the presence of Pmr1 or Pmc1. The Pmr1-dependent Mn(2+) tolerance of Vcx1-D1 requires the presence of calcineurin but not the functioning of the Ca(2+)/calcineurin signaling pathway. Similar to the wild-type Vcx1, C-terminally green fluorescent protein tagged Vcx1-D1 and Vcx1-M1 mutants localize to the endoplasmic reticulum instead of its normal vacuolar destination, but they remain functional in Ca(2+) sensitivity and Mn(2+) tolerance.
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Affiliation(s)
- Yunying Zhao
- a The State Key Laboratory of Food Science and Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, People's Republic of China.,b The National Engineering Laboratory for Cereal Fermentation Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Huihui Xu
- b The National Engineering Laboratory for Cereal Fermentation Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Yan Zhang
- b The National Engineering Laboratory for Cereal Fermentation Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, People's Republic of China
| | - Linghuo Jiang
- a The State Key Laboratory of Food Science and Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, People's Republic of China.,b The National Engineering Laboratory for Cereal Fermentation Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, People's Republic of China
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12
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García-Rodríguez N, Manzano-López J, Muñoz-Bravo M, Fernández-García E, Muñiz M, Wellinger RE. Manganese redistribution by calcium-stimulated vesicle trafficking bypasses the need for P-type ATPase function. J Biol Chem 2015; 290:9335-47. [PMID: 25713143 DOI: 10.1074/jbc.m114.616334] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Indexed: 12/31/2022] Open
Abstract
Regulation of intracellular ion homeostasis is essential for eukaryotic cell physiology. An example is provided by loss of ATP2C1 function, which leads to skin ulceration, improper keratinocyte adhesion, and cancer formation in Hailey-Hailey patients. The yeast ATP2C1 orthologue PMR1 codes for a Mn(2+)/Ca(2+) transporter that is crucial for cis-Golgi manganese supply. Here, we present evidence that calcium overcomes the lack of Pmr1 through vesicle trafficking-stimulated manganese delivery and requires the endoplasmic reticulum Mn(2+) transporter Spf1 and the late endosome/trans-Golgi Nramp metal transporter Smf2. Smf2 co-localizes with the putative Mn(2+) transporter Atx2, and ATX2 overexpression counteracts the beneficial impact of calcium treatment. Our findings suggest that vesicle trafficking promotes organelle-specific ion interchange and cytoplasmic metal detoxification independent of calcineurin signaling or metal transporter re-localization. Our study identifies an alternative mode for cis-Golgi manganese supply in yeast and provides new perspectives for Hailey-Hailey disease treatment.
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Affiliation(s)
- Néstor García-Rodríguez
- From the Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, 41092, Sevilla, Spain and
| | - Javier Manzano-López
- the Departamento de Biolgía Celular-Instituto de Biomedicina de Sevilla (IBiS), Universidad de Sevilla, 41012 Sevilla, Spain
| | - Miguel Muñoz-Bravo
- From the Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, 41092, Sevilla, Spain and
| | - Elisabet Fernández-García
- From the Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, 41092, Sevilla, Spain and
| | - Manuel Muñiz
- the Departamento de Biolgía Celular-Instituto de Biomedicina de Sevilla (IBiS), Universidad de Sevilla, 41012 Sevilla, Spain
| | - Ralf Erik Wellinger
- From the Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, 41092, Sevilla, Spain and
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13
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Migocka M, Kosieradzka A, Papierniak A, Maciaszczyk-Dziubinska E, Posyniak E, Garbiec A, Filleur S. Two metal-tolerance proteins, MTP1 and MTP4, are involved in Zn homeostasis and Cd sequestration in cucumber cells. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1001-15. [PMID: 25422498 DOI: 10.1093/jxb/eru459] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Metal-tolerance proteins (MTPs) are divalent cation transporters that have been shown to be essential for metal homeostasis and tolerance in model plants and hyperaccumulators. Due to the lack of genomic resources, studies on MTPs in cultivated crops are lacking. Here, we present the first functional characterization of genes encoding cucumber proteins homologous to MTP1 and MTP4 transporters. CsMTP1 expression was ubiquitous in cucumber plants, whereas CsMTP4 mRNA was less abundant and was not detected in the generative parts of the flowers. When expressed in yeast, CsMTP1 and CsMTP4 were able to complement the hypersensitivity of mutant strains to Zn and Cd through the increased sequestration of metals within vacuoles using the transmembrane electrochemical gradient. Both proteins formed oligomers at the vacuolar membranes of yeast and cucumber cells and localized in Arabidopsis protoplasts, consistent with their function in vacuolar Zn and Cd sequestration. Changes in the abundance of CsMTP1 and CsMTP4 transcripts and proteins in response to elevated Zn and Cd, or to Zn deprivation, suggested metal-induced transcriptional, translational, and post-translational modifications of protein activities. The differences in the organ expression and affinity of both proteins to Zn and Cd suggested that CsMTP1 and CsMTP4 may not be functionally redundant in cucumber cells.
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Affiliation(s)
- Magdalena Migocka
- Department of Molecular Plant Physiology, Wroclaw University, Institute of Experimental Biology, Kanonia 6/8, 50-328 Wroclaw, Poland
| | - Anna Kosieradzka
- Department of Molecular Plant Physiology, Wroclaw University, Institute of Experimental Biology, Kanonia 6/8, 50-328 Wroclaw, Poland
| | - Anna Papierniak
- Department of Molecular Plant Physiology, Wroclaw University, Institute of Experimental Biology, Kanonia 6/8, 50-328 Wroclaw, Poland
| | - Ewa Maciaszczyk-Dziubinska
- Department of Genetics and Cell Physiology, Wroclaw University, Institute of Experimental Biology, Kanonia 6/8, 50-328 Wroclaw, Poland
| | - Ewelina Posyniak
- Department of Molecular Plant Physiology, Wroclaw University, Institute of Experimental Biology, Kanonia 6/8, 50-328 Wroclaw, Poland
| | - Arnold Garbiec
- Department of Animal Developmental Biology, Wroclaw University, Institute of Experimental Biology, Sienkiewicza 21, 50-335 Wroclaw, Poland
| | - Sophie Filleur
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique (CNRS), 1 Avenue de la Terrasse, Saclay Plant Sciences Labex, 91198 Gif-Sur-Yvette Cedex, France Université Paris 7-Denis Diderot, UFR Sciences du Vivant, 35 rue Hélène Brion, 75205 Paris Cedex 13, France
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14
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Components of the calcium-calcineurin signaling pathway in fungal cells and their potential as antifungal targets. EUKARYOTIC CELL 2015; 14:324-34. [PMID: 25636321 DOI: 10.1128/ec.00271-14] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In recent years, the emergence of fungal resistance has become frequent, partly due to the widespread clinical use of fluconazole, which is minimally toxic and effective in the prevention and treatment of Candida albicans infections. The limited selection of antifungal drugs for clinical fungal infection therapy has prompted us to search for new antifungal drug targets. Calcium, which acts as the second messenger in both mammals and fungi, plays a direct role in controlling the expression patterns of its signaling systems and has important roles in cell survival. In addition, calcium and some of the components, mainly calcineurin, in the fungal calcium signaling pathway mediate fungal resistance to antifungal drugs. Therefore, an overview of the components of the fungal calcium-calcineurin signaling network and their potential roles as antifungal targets is urgently needed. The calcium-calcineurin signaling pathway consists of various channels, transporters, pumps, and other proteins or enzymes. Many transcriptional profiles have indicated that mutant strains that lack some of these components are sensitized to fluconazole or other antifungal drugs. In addition, many researchers have identified efficient compounds that exhibit antifungal activity by themselves or in combination with antifungal drugs by targeting some of the components in the fungal calcium-calcineurin signaling pathway. This targeting disrupts Ca(2+) homeostasis, which suggests that this pathway contains potential targets for the development of new antifungal drugs.
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Manzano-Lopez J, Perez-Linero AM, Aguilera-Romero A, Martin ME, Okano T, Silva DV, Seeberger PH, Riezman H, Funato K, Goder V, Wellinger RE, Muñiz M. COPII coat composition is actively regulated by luminal cargo maturation. Curr Biol 2014; 25:152-162. [PMID: 25557665 DOI: 10.1016/j.cub.2014.11.039] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/12/2014] [Accepted: 11/14/2014] [Indexed: 01/18/2023]
Abstract
BACKGROUND Export from the ER is an essential process driven by the COPII coat, which forms vesicles at ER exit sites (ERESs) to transport mature secretory proteins to the Golgi. Although the basic mechanism of COPII assembly is known, how COPII machinery is regulated to meet varying cellular secretory demands is unclear. RESULTS Here, we report a specialized COPII system that is actively recruited by luminal cargo maturation. Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are luminal secretory proteins anchored to the membrane by the glycolipid GPI. After protein attachment in the ER lumen, lipid and glycan parts of the GPI anchor are remodeled. In yeast, GPI-lipid remodeling concentrates GPI-APs into specific ERESs. We found that GPI-glycan remodeling induces subsequent recruitment of the specialized ER export machinery that enables vesicle formation from these specific ERESs. First, the transmembrane cargo receptor p24 complex binds GPI-APs as a lectin by recognizing the remodeled GPI-glycan. Binding of remodeled cargo induces the p24 complex to recruit the COPII subtype Lst1p, specifically required for GPI-AP ER export. CONCLUSIONS Our results show that COPII coat recruitment by cargo receptors is not constitutive but instead is actively regulated by binding of mature ligands. Therefore, we reveal a novel functional link between luminal cargo maturation and COPII vesicle budding, providing a mechanism to adjust specialized COPII vesicle production to the amount and quality of their luminal cargos that are ready for ER exit. This helps to understand how the ER export machinery adapts to different needs for luminal cargo secretion.
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Affiliation(s)
| | | | | | - Maria E Martin
- Department of Cell Biology, University of Seville, 41012 Seville, Spain
| | - Tatsuki Okano
- Department of Bioresource Science and Technology, Hiroshima University, Hiroshima 739-8528, Japan
| | - Daniel Varon Silva
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Peter H Seeberger
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Howard Riezman
- NCCR Chemical Biology and Department of Biochemistry, Sciences II, University of Geneva, 1211 Geneva 4, Switzerland
| | - Kouichi Funato
- Department of Bioresource Science and Technology, Hiroshima University, Hiroshima 739-8528, Japan
| | - Veit Goder
- Department of Genetics, University of Seville, 41012 Seville, Spain
| | - Ralf E Wellinger
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), 41092 Seville, Spain
| | - Manuel Muñiz
- Department of Cell Biology, University of Seville, 41012 Seville, Spain.
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Migocka M, Papierniak A, Maciaszczyk-Dziubińska E, Poździk P, Posyniak E, Garbiec A, Filleur S. Cucumber metal transport protein MTP8 confers increased tolerance to manganese when expressed in yeast and Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5367-84. [PMID: 25039075 PMCID: PMC4400539 DOI: 10.1093/jxb/eru295] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Cation diffusion facilitator (CDF) proteins are ubiquitous divalent cation transporters that have been proved to be essential for metal homeostasis and tolerance in Archaebacteria, Bacteria, and Eukaryota. In plants, CDFs are designated as metal tolerance proteins (MTPs). Due to the lack of genomic resources, studies on MTPs in other plants, including cultivated crops, are lacking. Here, the identification and organization of genes encoding members of the MTP family in cucumber are described. The first functional characterization of a cucumber gene encoding a member of the Mn-CDF subgroup of CDF proteins, designated as CsMTP8 based on the highest homology to plant MTP8, is also presented. The expression of CsMTP8 in Saccharomyces cerevisiae led to increased Mn accumulation in yeast cells and fully restored the growth of mutants hypersensitive to Mn in Mn excess. Similarly, the overexpression of CsMTP8 in Arabidopsis thaliana enhanced plant tolerance to high Mn in nutrition media as well as the accumulation of Mn in plant tissues. When fused to green fluorescent protein (GFP), CsMTP8 localized to the vacuolar membranes in yeast cells and to Arabidopsis protoplasts. In cucumber, CsMTP8 was expressed almost exclusively in roots, and the level of gene transcript was markedly up-regulated or reduced under elevated Mn or Mn deficiency, respectively. Taken together, the results suggest that CsMTP8 is an Mn transporter localized in the vacuolar membrane, which participates in the maintenance of Mn homeostasis in cucumber root cells.
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Affiliation(s)
- Magdalena Migocka
- Wrocław University, Institute of Experimental Biology, Department of Molecular Plant Physiology, Kanonia 6/8, 50-328 Wrocław, Poland
| | - Anna Papierniak
- Wrocław University, Institute of Experimental Biology, Department of Molecular Plant Physiology, Kanonia 6/8, 50-328 Wrocław, Poland
| | - Ewa Maciaszczyk-Dziubińska
- Wrocław University, Institute of Experimental Biology, Department of Genetics and Cell Physiology, Kanonia 6/8, 50-328 Wrocław, Poland
| | - Piotr Poździk
- Wrocław University, Institute of Experimental Biology, Department of Molecular Plant Physiology, Kanonia 6/8, 50-328 Wrocław, Poland
| | - Ewelina Posyniak
- Wrocław University, Institute of Experimental Biology, Department of Molecular Plant Physiology, Kanonia 6/8, 50-328 Wrocław, Poland
| | - Arnold Garbiec
- Wrocław University, Institute of Experimental Biology, Department of Animal Developmental Biology, Sienkiewicza 21, 50-335 Wrocław, Poland
| | - Sophie Filleur
- Institut des Sciences du Végétal, CNRS, 1 Avenue de la Terrasse, Saclay Plant Sciences Labex, 91198 Gif-Sur-Yvette Cedex, France Université Paris 7-Denis Diderot, UFR Sciences du Vivant, Saclay Plant Sciences Labex, 91198 Gif-Sur-Yvette Cedex, France
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Hu Y, Wang J, Ying SH, Feng MG. Five vacuolar Ca(2+) exchangers play different roles in calcineurin-dependent Ca(2+)/Mn(2+) tolerance, multistress responses and virulence of a filamentous entomopathogen. Fungal Genet Biol 2014; 73:12-9. [PMID: 25256588 DOI: 10.1016/j.fgb.2014.09.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 08/28/2014] [Accepted: 09/16/2014] [Indexed: 11/28/2022]
Abstract
Multiple Vcx1 (vacuolar calcium exchanger) paralogues exist in many filamentous fungi but are functionally unexplored unlike a single Vcx1 ortholog well characterized in yeasts. Here we show that five Vcx1 paralogues (Vcx1A-E) in Beauveria bassiana are conditionally functional for intracellular Ca(2+) homeostasis and contribute differentially to multistress tolerance and virulence in the filamentous entomopathogen. Each vcx1 deletion drastically upregulated transcriptional expressions of four other partners and six P-type Ca(2+)-ATPases, resulting in elevated or lowered intracellular Ca(2+) concentration in some deletion mutants treated with Ca(2+) stress or untreated at 25 and 30 °C. When calcineurin was inactivated by cyclosporine A, Ca(2+) tolerance decreased by 11-17% in five Δvcx1 mutants, but Mn(2+) sensitivity increased only in Δvcx1A and Δvcx1D, at optimal 25 °C. These two mutants were also more sensitive to Ca(2+) stress at 30 °C when calcineurin was active, and showed minor growth defect at 25 and 30 °C when calcineurin was inactive. Moreover, all the Δvcx1 mutants were more sensitive to dithiothreitol (stress-response trigger to endoplasmic reticulum) and Congo red (cell wall stressor); three of them were consistently less tolerant to the oxidants menadione and H2O2. The fungal virulence to Galleria mellonella larvae decreased by 15-40% in four Δvcx1 mutants excluding Δvcx1E, which was uniquely defective in conidial thermotolerance. All the changes were restored by each vcx1 complementation. Our findings indicate that the five Vcx1 paralogues in B. bassiana contribute differentially to calcineurin-dependent Ca(2+)/Mn(2+) tolerance, multistress responses and virulence, and recall attention to multifunctional Vcx1 paralogues in filamentous fungi.
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Affiliation(s)
- Yue Hu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Jie Wang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China.
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18
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A novel role of the vacuolar calcium channel Yvc1 in stress response, morphogenesis and pathogenicity of Candida albicans. Int J Med Microbiol 2013; 304:339-50. [PMID: 24368068 DOI: 10.1016/j.ijmm.2013.11.022] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 11/13/2013] [Accepted: 11/30/2013] [Indexed: 11/23/2022] Open
Abstract
C. albicans is a common opportunistic pathogen, causing both superficial and life-threatening systemic infections. Calcium signaling is an intriguing aspect in its physiology, attributing to the roles in stress response and morphogenesis. Until recently, little was known about the mechanisms by which the calcium signaling-associated elements affect its pathogenicity. In this study, we found that Yvc1, a member of the transient receptor potential (TRP) family, localized on the vacuolar membrane. The yvc1Δ/Δ mutant displayed decreased ability of stress response, morphogenesis and attenuated virulence. The Spitzenkörper required for polarized growth were not detected in the hyphal tip of this mutant, suggesting a key role of Yvc1 in hyphal polarized growth and re-orientation to host signals. This study demonstrates, for the first time, that the putative vacuolar calcium channel Yvc1 plays an important role in C. albicans infection and survival in host tissues, which is associated with its pleiotropic effects in several fungal physiological processes, including stress response, morphogenesis, and polarized growth.
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Abstract
All living organisms require nutrient minerals for growth and have developed mechanisms to acquire, utilize, and store nutrient minerals effectively. In the aqueous cellular environment, these elements exist as charged ions that, together with protons and hydroxide ions, facilitate biochemical reactions and establish the electrochemical gradients across membranes that drive cellular processes such as transport and ATP synthesis. Metal ions serve as essential enzyme cofactors and perform both structural and signaling roles within cells. However, because these ions can also be toxic, cells have developed sophisticated homeostatic mechanisms to regulate their levels and avoid toxicity. Studies in Saccharomyces cerevisiae have characterized many of the gene products and processes responsible for acquiring, utilizing, storing, and regulating levels of these ions. Findings in this model organism have often allowed the corresponding machinery in humans to be identified and have provided insights into diseases that result from defects in ion homeostasis. This review summarizes our current understanding of how cation balance is achieved and modulated in baker's yeast. Control of intracellular pH is discussed, as well as uptake, storage, and efflux mechanisms for the alkali metal cations, Na(+) and K(+), the divalent cations, Ca(2+) and Mg(2+), and the trace metal ions, Fe(2+), Zn(2+), Cu(2+), and Mn(2+). Signal transduction pathways that are regulated by pH and Ca(2+) are reviewed, as well as the mechanisms that allow cells to maintain appropriate intracellular cation concentrations when challenged by extreme conditions, i.e., either limited availability or toxic levels in the environment.
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The Plasmodium berghei Ca(2+)/H(+) exchanger, PbCAX, is essential for tolerance to environmental Ca(2+) during sexual development. PLoS Pathog 2013; 9:e1003191. [PMID: 23468629 PMCID: PMC3585132 DOI: 10.1371/journal.ppat.1003191] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 12/28/2012] [Indexed: 12/15/2022] Open
Abstract
Ca(2+) contributes to a myriad of important cellular processes in all organisms, including the apicomplexans, Plasmodium and Toxoplasma. Due to its varied and essential roles, free Ca(2+) is tightly regulated by complex mechanisms. These mechanisms are therefore of interest as putative drug targets. One pathway in Ca(2+) homeostatic control in apicomplexans uses a Ca(2+)/H(+) exchanger (a member of the cation exchanger family, CAX). The P. falciparum CAX (PfCAX) has recently been characterised in asexual blood stage parasites. To determine the physiological importance of apicomplexan CAXs, tagging and knock-out strategies were undertaken in the genetically tractable T. gondii and P. berghei parasites. In addition, a yeast heterologous expression system was used to study the function of apicomplexan CAXs. Tagging of T. gondii and P. berghei CAXs (TgCAX and PbCAX) under control of their endogenous promoters could not demonstrate measureable expression of either CAX in tachyzoites and asexual blood stages, respectively. These results were consistent with the ability of parasites to tolerate knock-outs of the genes for TgCAX and PbCAX at these developmental stages. In contrast, PbCAX expression was detectable during sexual stages of development in female gametocytes/gametes, zygotes and ookinetes, where it was dispersed in membranous networks within the cytosol (with minimal mitochondrial localisation). Furthermore, genetically disrupted parasites failed to develop further from "round" form zygotes, suggesting that PbCAX is essential for ookinete development and differentiation. This impeded phenotype could be rescued by removal of extracellular Ca(2+). Therefore, PbCAX provides a mechanism for free living parasites to multiply within the ionic microenvironment of the mosquito midgut. Ca(2+) homeostasis mediated by PbCAX is critical and suggests plasmodial CAXs may be targeted in approaches designed to block parasite transmission.
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21
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Salcedo-Sora JE, Ward SA, Biagini GA. A yeast expression system for functional and pharmacological studies of the malaria parasite Ca²⁺/H⁺ antiporter. Malar J 2012; 11:254. [PMID: 22853777 PMCID: PMC3488005 DOI: 10.1186/1475-2875-11-254] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2012] [Accepted: 07/23/2012] [Indexed: 12/26/2022] Open
Abstract
Background Calcium (Ca2+) signalling is fundamental for host cell invasion, motility, in vivo synchronicity and sexual differentiation of the malaria parasite. Consequently, cytoplasmic free Ca2+ is tightly regulated through the co-ordinated action of primary and secondary Ca2+ transporters. Identifying selective inhibitors of Ca2+ transporters is key towards understanding their physiological role as well as having therapeutic potential, therefore screening systems to facilitate the search for potential inhibitors are a priority. Here, the methodology for the expression of a Calcium membrane transporter that can be scaled to high throughputs in yeast is presented. Methods The Plasmodium falciparum Ca2+/H+ antiporter (PfCHA) was expressed in the yeast Saccharomyces cerevisiae and its activity monitored by the bioluminescence from apoaequorin triggered by divalent cations, such as calcium, magnesium and manganese. Results Bioluminescence assays demonstrated that PfCHA effectively suppressed induced cytoplasmic peaks of Ca2+, Mg2+ and Mn2+ in yeast mutants lacking the homologue yeast antiporter Vcx1p. In the scalable format of 96-well culture plates pharmacological assays with a cation antiporter inhibitor allowed the measurement of inhibition of the Ca2+ transport activity of PfCHA conveniently translated to the familiar concept of fractional inhibitory concentrations. Furthermore, the cytolocalization of this antiporter in the yeast cells showed that whilst PfCHA seems to locate to the mitochondrion of P. falciparum, in yeast PfCHA is sorted to the vacuole. This facilitates the real-time Ca2+-loading assays for further functional and pharmacological studies. Discussion The functional expression of PfCHA in S. cerevisiae and luminescence-based detection of cytoplasmic cations as presented here offer a tractable system that facilitates functional and pharmacological studies in a high-throughput format. PfCHA is shown to behave as a divalent cation/H+ antiporter susceptible to the effects of cation/H+ inhibitors such as KB-R7943. This type of gene expression systems should advance the efforts for the screening of potential inhibitors of this type of divalent cation transporters as part of the malaria drug discovery initiatives and for functional studies in general. Conclusion The expression and activity of the PfCHA detected in yeast by a bioluminescence assay that follows the levels of cytoplasmic Ca2+ as well as Mg2+ and Mn2+ lend itself to high-throughput and quantitative settings for pharmacological screening and functional studies.
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22
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García-Rodríguez N, Díaz de la Loza MDC, Andreson B, Monje-Casas F, Rothstein R, Wellinger RE. Impaired manganese metabolism causes mitotic misregulation. J Biol Chem 2012; 287:18717-29. [PMID: 22493290 DOI: 10.1074/jbc.m112.358309] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Manganese is an essential trace element, whose intracellular levels need to be carefully regulated. Mn(2+) acts as a cofactor for many enzymes and excess of Mn(2+) is toxic. Alterations in Mn(2+) homeostasis affect metabolic functions and mutations in the human Mn(2+)/Ca(2+) transporter ATP2C1 have been linked to Hailey-Hailey disease. By deletion of the yeast orthologue PMR1 we have studied the impact of Mn(2+) on cell cycle progression and show that an excess of cytosolic Mn(2+) alters S-phase transit, induces transcriptional up-regulation of cell cycle regulators, bypasses the need for S-phase cell cycle checkpoints and predisposes to genomic instability. On the other hand, we find that depletion of the Golgi Mn(2+) pool requires a functional morphology checkpoint to avoid the formation of polyploid cells.
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Affiliation(s)
- Néstor García-Rodríguez
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC, Sevilla, Spain
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23
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Mielniczki-Pereira AA, Hahn ABB, Bonatto D, Riger CJ, Eleutherio ECA, Henriques JAP. New insights into the Ca2+-ATPases that contribute to cadmium tolerance in yeast. Toxicol Lett 2011; 207:104-11. [PMID: 21911041 DOI: 10.1016/j.toxlet.2011.08.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/29/2011] [Accepted: 08/29/2011] [Indexed: 01/16/2023]
Abstract
Cadmium (Cd(2+)) is a toxic heavy metal which triggers several toxic effects in eukaryotes, including neurotoxicity and impaired calcium metabolism. In the model organism Saccharomyces cerevisiae, the best characterized pathway for Cd(2+) detoxification involves conjugation with glutathione (GSH) and subsequent transport to vacuoles by Ycf1p, an ATPase homologous to human MRP1 (Multidrug resistance associated protein 1). However, Cd(2+) tolerance also can be mediated by Pmr1p, a Ca(2+) pump located in the Golgi membrane, possibly through to the secretory pathway. Herein, we showed that inactivation of the PMR1 gene, alone or simultaneously with YCF1, delayed initial Cd(2+) capture compared to wild-type (WT) cells. In addition, Cd(2+) treatment altered the expression profile of yeast internal Ca(2+) transporters; specifically, PMC1 gene expression is induced substantially by the metal in WT cells, and this induction is stronger in mutants lacking YCF1. Taken together, these results indicate that, in addition to Pmr1p, the vacuolar Ca(2+)-ATPase Pmc1p also helps yeast cells cope with Cd(2+) toxicity. We propose a model where Pmc1p and Pmr1p Ca(2+)-ATPase function in cooperation with Ycf1p to promote Cd(2+) detoxification.
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Manohar M, Shigaki T, Hirschi KD. Plant cation/H+ exchangers (CAXs): biological functions and genetic manipulations. PLANT BIOLOGY (STUTTGART, GERMANY) 2011; 13:561-9. [PMID: 21668596 DOI: 10.1111/j.1438-8677.2011.00466.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Inorganic cations play decisive roles in many cellular and physiological processes and are essential components of plant nutrition. Therefore, the uptake of cations and their redistribution must be precisely controlled. Vacuolar antiporters are important elements in mediating the intracellular sequestration of these cations. These antiporters are energized by the proton gradient across the vacuolar membrane and allow the rapid transport of cations into the vacuole. CAXs (for CAtion eXchanger) are members of a multigene family and appear to predominately reside on vacuoles. Defining CAX regulation and substrate specificity have been aided by utilising yeast as an experimental tool. Studies in plants suggest CAXs regulate apoplastic Ca(2+) levels in order to optimise cell wall expansion, photosynthesis, transpiration and plant productivity. CAX studies provide the basis for making designer transporters that have been used to develop nutrient enhanced crops and plants for remediating toxic soils.
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Affiliation(s)
- M Manohar
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX 77030, USA
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Cunningham KW. Acidic calcium stores of Saccharomyces cerevisiae. Cell Calcium 2011; 50:129-38. [PMID: 21377728 DOI: 10.1016/j.ceca.2011.01.010] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 01/25/2011] [Accepted: 01/31/2011] [Indexed: 02/06/2023]
Abstract
Fungi and animals constitute sister kingdoms in the eukaryotic domain of life. The major classes of transporters, channels, sensors, and effectors that move and respond to calcium ions were already highly networked in the common ancestor of fungi and animals. Since that time, some key components of the network have been moved, altered, relocalized, lost, or duplicated in the fungal and animal lineages and at the same time some of the regulatory circuitry has been dramatically rewired. Today the calcium transport and signaling networks in fungi provide a fresh perspective on the scene that has emerged from studies of the network in animal cells. This review provides an overview of calcium signaling networks in fungi, particularly the model yeast Saccharomyces cerevisiae, with special attention to the dominant roles of acidic calcium stores in fungal cell physiology.
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Affiliation(s)
- Kyle W Cunningham
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA.
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Pittman JK. Vacuolar Ca(2+) uptake. Cell Calcium 2011; 50:139-46. [PMID: 21310481 DOI: 10.1016/j.ceca.2011.01.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 12/31/2010] [Accepted: 01/03/2011] [Indexed: 12/22/2022]
Abstract
Calcium transporters that mediate the removal of Ca(2+) from the cytosol and into internal stores provide a critical role in regulating Ca(2+) signals following stimulus induction and in preventing calcium toxicity. The vacuole is a major calcium store in many organisms, particularly plants and fungi. Two main pathways facilitate the accumulation of Ca(2+) into vacuoles, Ca(2+)-ATPases and Ca(2+)/H(+) exchangers. Here I review the biochemical and regulatory features of these transporters that have been characterised in yeast and plants. These Ca(2+) transport mechanisms are compared with those being identified from other vacuolated organisms including algae and protozoa. Studies suggest that Ca(2+) uptake into vacuoles and other related acidic Ca(2+) stores occurs by conserved mechanisms which developed early in evolution.
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Affiliation(s)
- Jon K Pittman
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
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The vacuolar Ca²(+) exchanger Vcx1 is involved in calcineurin-dependent Ca²(+) tolerance and virulence in Cryptococcus neoformans. EUKARYOTIC CELL 2010; 9:1798-805. [PMID: 20889719 DOI: 10.1128/ec.00114-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cryptococcus neoformans is an encapsulated yeast that causes a life-threatening meningoencephalitis in immunocompromised individuals. The ability to survive and proliferate at the human body temperature is an essential virulence attribute of this pathogen. This trait is controlled in part by the Ca²(+)-calcineurin pathway, which senses and utilizes cytosolic calcium for signaling. In the present study, the identification of the C. neoformans gene VCX1, which encodes a vacuolar calcium exchanger, is reported. The VCX1 knockout results in hypersensitivity to the calcineurin inhibitor cyclosporine A at 35°C, but not at 30°C. Furthermore, high concentrations of CaCl₂ lead to growth inhibition of the vcx1 mutant strain only in the presence of cyclosporine A, indicating that Vcx1 acts in parallel with calcineurin. The loss of VCX1 does not influence cell wall integrity or capsule size but decreases secretion of the major capsular polysaccharide glucuronoxylomannan (GXM) in culture supernatants.Vcx1 also influences C. neoformans phagocytosis by murine macrophages and is required for full virulence in mice. Analysis of cellular distribution by confocal microscopy confirmed the vacuolar localization of Vcx1 in C. neoformans cells.
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Cagnac O, Aranda-Sicilia MN, Leterrier M, Rodriguez-Rosales MP, Venema K. Vacuolar cation/H+ antiporters of Saccharomyces cerevisiae. J Biol Chem 2010; 285:33914-22. [PMID: 20709757 DOI: 10.1074/jbc.m110.116590] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously demonstrated that Saccharomyces cerevisiae vnx1Δ mutant strains displayed an almost total loss of Na(+) and K(+)/H(+) antiporter activity in a vacuole-enriched fraction. However, using different in vitro transport conditions, we were able to reveal additional K(+)/H(+) antiporter activity. By disrupting genes encoding transporters potentially involved in the vnx1 mutant strain, we determined that Vcx1p is responsible for this activity. This result was further confirmed by complementation of the vnx1Δvcx1Δ nhx1Δ triple mutant with Vcx1p and its inactivated mutant Vcx1p-H303A. Like the Ca(2+)/H(+) antiporter activity catalyzed by Vcx1p, the K(+)/H(+) antiporter activity was strongly inhibited by Cd(2+) and to a lesser extend by Zn(2+). Unlike as previously observed for NHX1 or VNX1, VCX1 overexpression only marginally improved the growth of yeast strain AXT3 in the presence of high concentrations of K(+) and had no effect on hygromycin sensitivity. Subcellular localization showed that Vcx1p and Vnx1p are targeted to the vacuolar membrane, whereas Nhx1p is targeted to prevacuoles. The relative importance of Nhx1p, Vnx1p, and Vcx1p in the vacuolar accumulation of monovalent cations will be discussed.
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Affiliation(s)
- Olivier Cagnac
- Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estacion Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Apartado 419, E-18080 Granada, Spain.
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29
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Abstract
The maintenance of appropriate intracellular concentrations of alkali metal cations, principally K(+) and Na(+), is of utmost importance for living cells, since they determine cell volume, intracellular pH, and potential across the plasma membrane, among other important cellular parameters. Yeasts have developed a number of strategies to adapt to large variations in the concentrations of these cations in the environment, basically by controlling transport processes. Plasma membrane high-affinity K(+) transporters allow intracellular accumulation of this cation even when it is scarce in the environment. Exposure to high concentrations of Na(+) can be tolerated due to the existence of an Na(+), K(+)-ATPase and an Na(+), K(+)/H(+)-antiporter, which contribute to the potassium balance as well. Cations can also be sequestered through various antiporters into intracellular organelles, such as the vacuole. Although some uncertainties still persist, the nature of the major structural components responsible for alkali metal cation fluxes across yeast membranes has been defined within the last 20 years. In contrast, the regulatory components and their interactions are, in many cases, still unclear. Conserved signaling pathways (e.g., calcineurin and HOG) are known to participate in the regulation of influx and efflux processes at the plasma membrane level, even though the molecular details are obscure. Similarly, very little is known about the regulation of organellar transport and homeostasis of alkali metal cations. The aim of this review is to provide a comprehensive and up-to-date vision of the mechanisms responsible for alkali metal cation transport and their regulation in the model yeast Saccharomyces cerevisiae and to establish, when possible, comparisons with other yeasts and higher plants.
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Gardarin A, Chédin S, Lagniel G, Aude JC, Godat E, Catty P, Labarre J. Endoplasmic reticulum is a major target of cadmium toxicity in yeast. Mol Microbiol 2010; 76:1034-48. [PMID: 20444096 DOI: 10.1111/j.1365-2958.2010.07166.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cadmium (Cd(2+)) is a very toxic metal that causes DNA damage, oxidative stress and apoptosis. Despite many studies, the cellular and molecular mechanisms underlying its high toxicity are not clearly understood. We show here that very low doses of Cd(2+) cause ER stress in Saccharomyces cerevisiae as evidenced by the induction of the unfolded protein response (UPR) and the splicing of HAC1 mRNA. Furthermore, mutant strains (Delta ire1 and Delta hac1) unable to induce the UPR are hypersensitive to Cd(2+), but not to arsenite and mercury. The full functionality of the pathways involved in ER stress response is required for Cd(2+) tolerance. The data also suggest that Cd(2+)-induced ER stress and Cd(2+) toxicity are a direct consequence of Cd(2+) accumulation in the ER. Cd(2+) does not inhibit disulfide bond formation but perturbs calcium metabolism. In particular, Cd(2+) activates the calcium channel Cch1/Mid1, which also contributes to Cd(2+) entry into the cell. The results reinforce the interest of using yeast as a cellular model to study toxicity mechanisms in eukaryotic cells.
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Affiliation(s)
- Aurélie Gardarin
- Equipe Transports et Régulations Intracellulaires de Métaux, LCBM/iRTSV, CEA/Grenoble, 17 rue des Martyrs, F-38054 Grenoble Cedex 9, France
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31
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Pittman JK, Edmond C, Sunderland PA, Bray CM. A cation-regulated and proton gradient-dependent cation transporter from Chlamydomonas reinhardtii has a role in calcium and sodium homeostasis. J Biol Chem 2008; 284:525-533. [PMID: 19001368 DOI: 10.1074/jbc.m807173200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The CrCAX1 gene encoding a Ca2+/H+ and Na+/H+ exchanger was cloned and characterized from the unicellular green alga Chlamydomonas reinhardtii to begin to understand the mechanisms of cation homeostasis in this model organism. CrCAX1 was more closely related to fungal cation exchanger (CAX) genes than those from higher plants but has structural characteristics similar to plant Ca2+/H+ exchangers including a long N-terminal tail. When CrCAX1-GFP was expressed in Saccharomyces cerevisiae, it localized at the vacuole. CrCAX1 could suppress the Ca2+-hypersensitive phenotype of a yeast mutant and mediated proton gradient-dependent Ca2+/H+ exchange activity in vacuolar membrane vesicles. Ca2+ transport activity was increased following N-terminal truncation of CrCAX1, suggesting the existence of an N-terminal auto-regulatory mechanism. CrCAX1 could also provide tolerance to Na+ stress when expressed in yeast or Arabidopsis thaliana because of Na+/H+ exchange activity. This Na+/H+ exchange activity was not regulated by the N terminus of the CrCAX1 protein. A subtle tolerance by CrCAX1 in yeast to Co2+ stress was also observed. CrCAX1 was transcriptionally regulated in Chlamydomonas cells grown in elevated Ca2+ or Na+. This study has thus uncovered a novel eukaryotic proton-coupled transporter, CrCAX1, that can transport both monovalent and divalent cations and that appears to play a role in cellular cation homeostasis by the transport of Ca2+ and Na+ into the vacuole.
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Affiliation(s)
- Jon K Pittman
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, United Kingdom.
| | - Clare Edmond
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Paul A Sunderland
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Clifford M Bray
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, United Kingdom
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32
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Morris J, Tian H, Park S, Sreevidya CS, Ward JM, Hirschi KD. AtCCX3 is an Arabidopsis endomembrane H+ -dependent K+ transporter. PLANT PHYSIOLOGY 2008; 148:1474-86. [PMID: 18775974 PMCID: PMC2577254 DOI: 10.1104/pp.108.118810] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 08/30/2008] [Indexed: 05/18/2023]
Abstract
The Arabidopsis (Arabidopsis thaliana) cation calcium exchangers (CCXs) were recently identified as a subfamily of cation transporters; however, no plant CCXs have been functionally characterized. Here, we show that Arabidopsis AtCCX3 (At3g14070) and AtCCX4 (At1g54115) can suppress yeast mutants defective in Na(+), K(+), and Mn(2+) transport. We also report high-capacity uptake of (86)Rb(+) in tonoplast-enriched vesicles from yeast expressing AtCCX3. Cation competition studies showed inhibition of (86)Rb(+) uptake in AtCCX3 cells by excess Na(+), K(+), and Mn(2+). Functional epitope-tagged AtCCX3 fusion proteins were localized to endomembranes in plants and yeast. In Arabidopsis, AtCCX3 is primarily expressed in flowers, while AtCCX4 is expressed throughout the plant. Quantitative polymerase chain reaction showed that expression of AtCCX3 increased in plants treated with NaCl, KCl, and MnCl(2). Insertional mutant lines of AtCCX3 and AtCCX4 displayed no apparent growth defects; however, overexpression of AtCCX3 caused increased Na(+) accumulation and increased (86)Rb(+) transport. Uptake of (86)Rb(+) increased in tonoplast-enriched membranes isolated from Arabidopsis lines expressing CCX3 driven by the cauliflower mosaic virus 35S promoter. Overexpression of AtCCX3 in tobacco (Nicotiana tabacum) produced lesions in the leaves, stunted growth, and resulted in the accumulation of higher levels of numerous cations. In summary, these findings suggest that AtCCX3 is an endomembrane-localized H(+)-dependent K(+) transporter with apparent Na(+) and Mn(2+) transport properties distinct from those of previously characterized plant transporters.
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Affiliation(s)
- Jay Morris
- Vegetable and Fruit Improvement Center, Texas A&M University, College Station, Texas 77845, USA
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33
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Topology mapping of the vacuolar Vcx1p Ca2+/H+ exchanger from Saccharomyces cerevisiae. Biochem J 2008; 414:133-41. [DOI: 10.1042/bj20080364] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Saccharomyces cerevisiae uses vacuolar storage to dynamically control the cytoplasmic calcium concentration. Vcx1p, a Ca2+/H+ antiporter and a member of the CAX (Ca2+/anion exchanger) family of exchangers, is one of the proteins that sequesters calcium into the vacuole. Although the biological importance of Vcx1p is clear, the molecular mechanism by which Vcx1p and its family members mediate Ca2+/H+ exchange activity remains poorly understood. To provide a basic structural framework for understanding functional studies of the CAX proteins, we have mapped Vcx1p's topology using three biochemical assays: C-terminal reporter localization, glycosylation mapping and proteolysis. We have found that the protein has an odd number of TM (transmembrane) domains and that its termini are located on opposite sides of the membrane, with the N-terminus in the cytoplasm. Our results indicate that loops 1, 3, 7 and 9 are luminal, while loops 6 and 8 are cytosolic. Our experimentally-based topology model for Vcx1p is in agreement with models derived from topology algorithms and with biochemical data reported by other groups. In addition, our studies suggest that the calcium domain, a nine-residue domain found to be critical for function in CAX proteins from plants, is not essential to Vcx1p activity.
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34
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Devasahayam G, Burke DJ, Sturgill TW. Golgi manganese transport is required for rapamycin signaling in Saccharomyces cerevisiae. Genetics 2007; 177:231-8. [PMID: 17603109 PMCID: PMC2013697 DOI: 10.1534/genetics.107.073577] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The Pmr1 Golgi Ca2+/Mn2+ ATPase negatively regulates target of rapamycin complex (TORC1) signaling, the rapamycin-sensitive TOR complex in Saccharomyces cerevisiae. Since pmr1 causes resistance to rapamycin and tor1 causes hypersensitivity, we looked for genetic interactions of pmr1 with tor1. Deletion of TOR1 restored two wild-type phenotypes. Loss of TOR1 restored the ability of the pmr1 strain to grow on media containing 2 mm MnCl2 and conferred wild type as well as the wild-type sensitivity to rapamycin. Mn2+ additions to media partially suppressed rapamycin resistance of wild type and pmr1 tor1, suggesting that Tor1 and Tor2 are regulated by manganese. We parsed the roles of Ca2+ and Mn2+ transport and the compartments in rapamycin response using separation-of-function mutants available for Pmr1. A strain containing the D53A mutant (Mn2+ transporting) of Pmr1 is rapamycin sensitive, but the Q783A mutant (Ca2+ transporting) strain is rapamycin resistant. Mn2+ transport into the Golgi lumen appears to be required for rapamycin sensitivity. Overexpression of Ca2+ pump SERCA1, Ca2+/H+ antiporter Vcx1, or a Mn2+ transporting mutant of Vcx1 (Vcx1-M1) failed to restore rapamycin sensitivity, and loss of Pmr1 but not other transporters of Ca2+ or Mn2+ results in rapamycin resistance. Overexpression of Ccc1, a Fe2+ and Mn2+ transporter that has been localized to Golgi and the vacuole, does restore rapamycin sensitivity to pmr1Delta. We conclude that Mn2+ in the Golgi inhibits TORC1 signaling.
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Affiliation(s)
- Gina Devasahayam
- Department of Pharmacology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908, USA
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35
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Shigaki T, Rees I, Nakhleh L, Hirschi KD. Identification of three distinct phylogenetic groups of CAX cation/proton antiporters. J Mol Evol 2006; 63:815-25. [PMID: 17086450 DOI: 10.1007/s00239-006-0048-4] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2006] [Accepted: 07/21/2006] [Indexed: 11/26/2022]
Abstract
Ca(2+)/cation antiporter (CaCA) proteins are integral membrane proteins that transport Ca(2+) or other cations using the H(+) or Na(+) gradient generated by primary transporters. The CAX (for CAtion eXchanger) family is one of the five families that make up the CaCA superfamily. CAX genes have been found in bacteria, Dictyostelium, fungi, plants, and lower vertebrates, but only a small number of CAXs have been functionally characterized. In this study, we explored the diversity of CAXs and their phylogenetic relationships. The results demonstrate that there are three major types of CAXs: type I (CAXs similar to Arabidopsis thaliana CAX1, found in plants, fungi, and bacteria), type II (CAXs with a long N-terminus hydrophilic region, found in fungi, Dictyostelium, and lower vertebrates), and type III (CAXs similar to Escherichia coli ChaA, found in bacteria). Some CAXs were found to have secondary structures that are different from the canonical six transmembrane (TM) domains-acidic motif-five TM domain structure. Our phylogenetic tree indicated no evidence to support the cyanobacterial origin of plant CAXs or the classification of Arabidopsis exchangers CAX7 to CAX11. For the first time, these results clearly define the CAX exchanger family and its subtypes in phylogenetic terms. The surprising diversity of CAXs demonstrates their potential range of biochemical properties and physiologic relevance.
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Affiliation(s)
- T Shigaki
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Room 9016, CNRC, 1100 Bates Street, Houston, TX 77030, USA.
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Shigaki T, Hirschi KD. Diverse functions and molecular properties emerging for CAX cation/H+ exchangers in plants. PLANT BIOLOGY (STUTTGART, GERMANY) 2006; 8:419-29. [PMID: 16906482 DOI: 10.1055/s-2006-923950] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Steep concentration gradients of many ions are actively maintained, with lower concentrations typically located in the cytosol, and higher concentrations in organelles and outside the cell. The vacuole is an important storage organelle for many ions. The concentration gradient of cations is established across the plant tonoplast, in part, by high-capacity cation/H+ (CAX) exchange activity. While plants may not be green yeast, analysis of CAX regulation and substrate specificity has been greatly aided by utilizing yeast as an experimental tool. The basic CAX biology in ARABIDOPSIS has immediate relevance toward understanding the functional interplay between diverse transport processes. The long-range applied goals are to identify novel transporters and express them in crop plants in order to "mine" nutrients out of the soil and into plants. In doing so, this could boost the levels of essential nutrients in plants.
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Affiliation(s)
- T Shigaki
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates St., Houston, TX 77030, USA.
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Park S, Cheng NH, Pittman JK, Yoo KS, Park J, Smith RH, Hirschi KD. Increased calcium levels and prolonged shelf life in tomatoes expressing Arabidopsis H+/Ca2+ transporters. PLANT PHYSIOLOGY 2005; 139:1194-206. [PMID: 16244156 PMCID: PMC1283758 DOI: 10.1104/pp.105.066266] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Here we demonstrate that fruit from tomato (Lycopersicon esculentum) plants expressing Arabidopsis (Arabidopsis thaliana) H(+)/cation exchangers (CAX) have more calcium (Ca2+) and prolonged shelf life when compared to controls. Previously, using the prototypical CAX1, it has been demonstrated that, in yeast (Saccharomyces cerevisiae) cells, CAX transporters are activated when the N-terminal autoinhibitory region is deleted, to give an N-terminally truncated CAX (sCAX), or altered through specific manipulations. To continue to understand the diversity of CAX function, we used yeast assays to characterize the putative transport properties of CAX4 and N-terminal variants of CAX4. CAX4 variants can suppress the Ca2+ hypersensitive yeast phenotypes and also appear to be more specific Ca2+ transporters than sCAX1. We then compared the phenotypes of sCAX1- and CAX4-expressing tomato lines. The sCAX1-expressing tomato lines demonstrate increased vacuolar H(+)/Ca2+ transport, when measured in root tissue, elevated fruit Ca2+ level, and prolonged shelf life but have severe alterations in plant development and morphology, including increased incidence of blossom-end rot. The CAX4-expressing plants demonstrate more modest increases in Ca2+ levels and shelf life but no deleterious effects on plant growth. These findings suggest that CAX expression may fortify plants with Ca2+ and may serve as an alternative to the application of CaCl2 used to extend the shelf life of numerous agriculturally important commodities. However, judicious regulation of CAX transport is required to assure optimal plant growth.
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Affiliation(s)
- Sunghun Park
- Vegetable and Fruit Improvement Center, Texas A&M University, College Station, TX 77845, USA
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Pittman JK. Managing the manganese: molecular mechanisms of manganese transport and homeostasis. THE NEW PHYTOLOGIST 2005; 167:733-42. [PMID: 16101910 DOI: 10.1111/j.1469-8137.2005.01453.x] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Manganese (Mn) is an essential metal nutrient for plants. Recently, some of the genes responsible for transition metal transport in plants have been identified; however, only relatively recently have Mn2+ transport pathways begun to be identified at the molecular level. These include transporters responsible for Mn accumulation into the cell and release from various organelles, and for active sequestration into endomembrane compartments, particularly the vacuole and the endoplasmic reticulum. Several transporter gene families have been implicated in Mn2+ transport, including cation/H+ antiporters, natural resistance-associated macrophage protein (Nramp) transporters, zinc-regulated transporter/iron-regulated transporter (ZRT/IRT1)-related protein (ZIP) transporters, the cation diffusion facilitator (CDF) transporter family, and P-type ATPases. The identification of mutants with altered Mn phenotypes can allow the identification of novel components in Mn homeostasis. In addition, the characterization of Mn hyperaccumulator plants can increase our understanding of how plants can adapt to excess Mn, and ultimately allow the identification of genes that confer this stress tolerance. The identification of genes responsible for Mn2+ transport has substantially improved our understanding of plant Mn homeostasis.
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Affiliation(s)
- Jon K Pittman
- Faculty of Life Sciences, University of Manchester, 3.614 Stopford Building, Oxford Road, Manchester M13 9PT, UK.
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39
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Current awareness on yeast. Yeast 2005; 22:503-10. [PMID: 15918233 DOI: 10.1002/yea.1162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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