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HRG-9 homologues regulate haem trafficking from haem-enriched compartments. Nature 2022; 610:768-774. [PMID: 36261532 PMCID: PMC9810272 DOI: 10.1038/s41586-022-05347-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 09/14/2022] [Indexed: 02/05/2023]
Abstract
Haem is an iron-containing tetrapyrrole that is critical for a variety of cellular and physiological processes1-3. Haem binding proteins are present in almost all cellular compartments, but the molecular mechanisms that regulate the transport and use of haem within the cell remain poorly understood2,3. Here we show that haem-responsive gene 9 (HRG-9) (also known as transport and Golgi organization 2 (TANGO2)) is an evolutionarily conserved haem chaperone with a crucial role in trafficking haem out of haem storage or synthesis sites in eukaryotic cells. Loss of Caenorhabditis elegans hrg-9 and its paralogue hrg-10 results in the accumulation of haem in lysosome-related organelles, the haem storage site in worms. Similarly, deletion of the hrg-9 homologue TANGO2 in yeast and mammalian cells induces haem overload in mitochondria, the site of haem synthesis. We demonstrate that TANGO2 binds haem and transfers it from cellular membranes to apo-haemoproteins. Notably, homozygous tango2-/- zebrafish larvae develop pleiotropic symptoms including encephalopathy, cardiac arrhythmia and myopathy, and die during early development. These defects partially resemble the symptoms of human TANGO2-related metabolic encephalopathy and arrhythmias, a hereditary disease caused by mutations in TANGO24-8. Thus, the identification of HRG-9 as an intracellular haem chaperone provides a biological basis for exploring the aetiology and treatment of TANGO2-related disorders.
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2
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Somai BM, Belewa V, Frost C. Tulbaghia violacea (Harv) Exerts its Antifungal Activity by Reducing Ergosterol Production in Aspergillus flavus. Curr Microbiol 2021; 78:2989-2997. [PMID: 34100987 DOI: 10.1007/s00284-021-02546-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/21/2021] [Indexed: 10/21/2022]
Abstract
Opportunistic infections in immunosuppressed patients have led to an increase in fungal infections, with Aspergillus being one of the main causative agents. Medicinal plants exhibiting antifungal activity have the potential to be used as chemotherapeutic agents. However, often their mechanisms of action are not fully researched. Tulbaghia violacea exhibits antifungal activity towards Candida, Aspergillus flavus and Aspergillus parasiticus but its mode of action has only recently begun to be investigated. This study aimed to ascertain the effect of T. violacea rhizome extracts on ergosterol production in A. flavus and the mechanism of inhibition. The MIC of a T. violacea rhizome extract against A. flavus was first determined, using a broth dilution assay, to be 15 mg/ml. Thereafter, the culture was subjected to sub-inhibitory concentrations of the extract before sterol intermediates of the ergosterol biosynthetic pathway were isolated and analysed for dose-dependent accumulation. Analysis by reverse-phase HPLC displayed a decline in ergosterol production in a dose-dependent manner when exposed to increasing concentrations of T. violacea extract. Quantification of the sterol intermediates of the ergosterol pathway indicated a definite accumulation of 2,3-oxidosqualene. The results prove that the plant extract affected ergosterol synthesis by inhibiting oxidosqualene cyclase. This prevented the formation of downstream intermediates of the ergosterol pathway ultimately resulting in inhibition of ergosterol production.
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Affiliation(s)
- Benesh M Somai
- Department of Biochemistry & Microbiology, Nelson Mandela University, University Way, Summerstrand, P.O. Box 77000, Port Elizabeth, Eastern Cape, South Africa.
| | - Vuyokazi Belewa
- Department of Biochemistry & Microbiology, Nelson Mandela University, University Way, Summerstrand, P.O. Box 77000, Port Elizabeth, Eastern Cape, South Africa
| | - Carminita Frost
- Department of Biochemistry & Microbiology, Nelson Mandela University, University Way, Summerstrand, P.O. Box 77000, Port Elizabeth, Eastern Cape, South Africa
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3
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Bhattacharya S, Sae-Tia S, Fries BC. Candidiasis and Mechanisms of Antifungal Resistance. Antibiotics (Basel) 2020; 9:antibiotics9060312. [PMID: 32526921 PMCID: PMC7345657 DOI: 10.3390/antibiotics9060312] [Citation(s) in RCA: 200] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/06/2020] [Accepted: 06/07/2020] [Indexed: 12/13/2022] Open
Abstract
Candidiasis can be present as a cutaneous, mucosal or deep-seated organ infection, which is caused by more than 20 types of Candida sp., with C. albicans being the most common. These are pathogenic yeast and are usually present in the normal microbiome. High-risk individuals are patients of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), organ transplant, and diabetes. During infection, pathogens can adhere to complement receptors and various extracellular matrix proteins in the oral and vaginal cavity. Oral and vaginal Candidiasis results from the overgrowth of Candida sp. in the hosts, causing penetration of the oral and vaginal tissues. Symptoms include white patches in the mouth, tongue, throat, and itchiness or burning of genitalia. Diagnosis involves visual examination, microscopic analysis, or culturing. These infections are treated with a variety of antifungals that target different biosynthetic pathways of the pathogen. For example, echinochandins target cell wall biosynthesis, while allylamines, azoles, and morpholines target ergosterol biosynthesis, and 5-Flucytosine (5FC) targets nucleic acid biosynthesis. Azoles are commonly used in therapeutics, however, because of its fungistatic nature, Candida sp. evolve azole resistance. Besides azoles, Candida sp. also acquire resistance to polyenes, echinochandins, and 5FC. This review discusses, in detail, the drug resistance mechanisms adapted by Candida sp.
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Affiliation(s)
- Somanon Bhattacharya
- Division of Infectious Diseases, Department of Medicine, Stony Brook University, Stony Brook, New York, NY 11794, USA; (S.S.-T.); (B.C.F.)
- Correspondence:
| | - Sutthichai Sae-Tia
- Division of Infectious Diseases, Department of Medicine, Stony Brook University, Stony Brook, New York, NY 11794, USA; (S.S.-T.); (B.C.F.)
| | - Bettina C. Fries
- Division of Infectious Diseases, Department of Medicine, Stony Brook University, Stony Brook, New York, NY 11794, USA; (S.S.-T.); (B.C.F.)
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, NY 11794, USA
- Veterans Administration Medical Center, Northport, New York, NY 11768, USA
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4
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Martinez-Guzman O, Willoughby MM, Saini A, Dietz JV, Bohovych I, Medlock AE, Khalimonchuk O, Reddi AR. Mitochondrial-nuclear heme trafficking in budding yeast is regulated by GTPases that control mitochondrial dynamics and ER contact sites. J Cell Sci 2020; 133:jcs.237917. [PMID: 32265272 DOI: 10.1242/jcs.237917] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 03/24/2020] [Indexed: 12/20/2022] Open
Abstract
Heme is a cofactor and signaling molecule that is essential for much of aerobic life. All heme-dependent processes in eukaryotes require that heme is trafficked from its site of synthesis in the mitochondria to hemoproteins located throughout the cell. However, the mechanisms governing the mobilization of heme out of the mitochondria, and the spatio-temporal dynamics of these processes, are poorly understood. Here, using genetically encoded fluorescent heme sensors, we developed a live-cell assay to monitor heme distribution dynamics between the mitochondrial inner membrane, where heme is synthesized, and the mitochondrial matrix, cytosol and nucleus. Surprisingly, heme trafficking to the nucleus is ∼25% faster than to the cytosol or mitochondrial matrix, which have nearly identical heme trafficking dynamics, potentially supporting a role for heme as a mitochondrial-nuclear retrograde signal. Moreover, we discovered that the heme synthetic enzyme 5-aminolevulinic acid synthase (ALAS, also known as Hem1 in yeast), and GTPases in control of the mitochondrial dynamics machinery (Mgm1 and Dnm1) and ER contact sites (Gem1), regulate the flow of heme between the mitochondria and nucleus. Overall, our results indicate that there are parallel pathways for the distribution of bioavailable heme.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Osiris Martinez-Guzman
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Mathilda M Willoughby
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Arushi Saini
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Jonathan V Dietz
- Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, USA
| | - Iryna Bohovych
- Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, USA
| | - Amy E Medlock
- Department of Biochemistry and Molecular Biology, University of Georgia and Augusta University-University of Georgia Medical Partnership, Athens, GA 30602, USA
| | - Oleh Khalimonchuk
- Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, USA.,Fred & Pamela Buffett Cancer Center, Omaha, NE 68198, USA
| | - Amit R Reddi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA .,Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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5
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Tesnière C. Importance and role of lipids in wine yeast fermentation. Appl Microbiol Biotechnol 2019; 103:8293-8300. [PMID: 31402425 DOI: 10.1007/s00253-019-10029-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/09/2019] [Accepted: 07/12/2019] [Indexed: 01/14/2023]
Abstract
This review summarizes the current knowledge on the importance and role of lipids in wine yeast fermentation. Lipids play an important role in membrane structure, adaptation to stress, or as signaling molecules. They are also essential nutrients whose availability can vary depending on winemaking technology, with major effects on yeast alcoholic fermentation. Moreover, lipid supplementation can greatly stimulate the formation of yeast volatile metabolites.
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Affiliation(s)
- Catherine Tesnière
- UMR SPO, INRA, Montpellier SupAgro, Université de Montpellier, Montpellier, France.
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6
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Montllor-Albalate C, Colin AE, Chandrasekharan B, Bolaji N, Andersen JL, Wayne Outten F, Reddi AR. Extra-mitochondrial Cu/Zn superoxide dismutase (Sod1) is dispensable for protection against oxidative stress but mediates peroxide signaling in Saccharomyces cerevisiae. Redox Biol 2019; 21:101064. [PMID: 30576923 PMCID: PMC6302037 DOI: 10.1016/j.redox.2018.11.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/13/2018] [Accepted: 11/29/2018] [Indexed: 02/06/2023] Open
Abstract
Cu/Zn Superoxide Dismutase (Sod1) is a highly conserved and abundant metalloenzyme that catalyzes the disproportionation of superoxide radicals into hydrogen peroxide and molecular oxygen. As a consequence, Sod1 serves dual roles in oxidative stress protection and redox signaling by both scavenging cytotoxic superoxide radicals and producing hydrogen peroxide that can be used to oxidize and regulate the activity of downstream targets. However, the relative contributions of Sod1 to protection against oxidative stress and redox signaling are poorly understood. Using the model unicellular eukaryote, Baker's yeast, we found that only a small fraction of the total Sod1 pool is required for protection against superoxide toxicity and that this pool is localized to the mitochondrial intermembrane space. On the contrary, we find that much larger amounts of extra-mitochondrial Sod1 are critical for peroxide-mediated redox signaling. Altogether, our results force the re-evaluation of the physiological role of bulk Sod1 in redox biology; namely, we propose that the vast majority of Sod1 in yeast is utilized for peroxide-mediated signaling rather than superoxide scavenging.
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Affiliation(s)
| | - Alyson E Colin
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Bindu Chandrasekharan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Naimah Bolaji
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
| | - Joshua L Andersen
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA
| | - F Wayne Outten
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
| | - Amit R Reddi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA; Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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7
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Sweeny EA, Singh AB, Chakravarti R, Martinez-Guzman O, Saini A, Haque MM, Garee G, Dans PD, Hannibal L, Reddi AR, Stuehr DJ. Glyceraldehyde-3-phosphate dehydrogenase is a chaperone that allocates labile heme in cells. J Biol Chem 2018; 293:14557-14568. [PMID: 30012884 DOI: 10.1074/jbc.ra118.004169] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/05/2018] [Indexed: 11/06/2022] Open
Abstract
Cellular heme is thought to be distributed between a pool of sequestered heme that is tightly bound within hemeproteins and a labile heme pool required for signaling and transfer into proteins. A heme chaperone that can hold and allocate labile heme within cells has long been proposed but never been identified. Here, we show that the glycolytic protein glyceraldehyde-3-phosphate dehydrogenase (GAPDH) fulfills this role by acting as an essential repository and allocator of bioavailable heme to downstream protein targets. We identified a conserved histidine in GAPDH that is needed for its robust heme binding both in vitro and in mammalian cells. Substitution of this histidine, and the consequent decreases in GAPDH heme binding, antagonized heme delivery to both cytosolic and nuclear hemeprotein targets, including inducible nitric-oxide synthase (iNOS) in murine macrophages and the nuclear transcription factor Hap1 in yeast, even though this GAPDH variant caused cellular levels of labile heme to rise dramatically. We conclude that by virtue of its heme-binding property, GAPDH binds and chaperones labile heme to create a heme pool that is bioavailable to downstream proteins. Our finding solves a fundamental question in cell biology and provides a new foundation for exploring heme homeostasis in health and disease.
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Affiliation(s)
- Elizabeth A Sweeny
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Anuradha Bharara Singh
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Ritu Chakravarti
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Osiris Martinez-Guzman
- the School of Chemistry and Biochemistry and Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Arushi Saini
- the School of Chemistry and Biochemistry and Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Mohammad Mahfuzul Haque
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Greer Garee
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195
| | - Pablo D Dans
- the Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology, Balidiri Reixac 10-12, Barcelona 08028, Spain, and
| | - Luciana Hannibal
- the Laboratory of Clinical Biochemistry and Metabolism, Center of Pediatrics, Medical Center, University of Freiburg, D-79106 Freiburg, Germany
| | - Amit R Reddi
- the School of Chemistry and Biochemistry and Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Dennis J Stuehr
- From the Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio 44195,
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8
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Hanna DA, Hu R, Kim H, Martinez-Guzman O, Torres MP, Reddi AR. Heme bioavailability and signaling in response to stress in yeast cells. J Biol Chem 2018; 293:12378-12393. [PMID: 29921585 DOI: 10.1074/jbc.ra118.002125] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 06/15/2018] [Indexed: 12/28/2022] Open
Abstract
Protoheme (hereafter referred to as heme) is an essential cellular cofactor and signaling molecule that is also potentially cytotoxic. To mitigate heme toxicity, heme synthesis and degradation are tightly coupled to heme utilization in order to limit the intracellular concentration of "free" heme. Such a model, however, would suggest that a readily accessible steady-state, bioavailable labile heme (LH) pool is not required for supporting heme-dependent processes. Using the yeast Saccharomyces cerevisiae as a model and fluorescent heme sensors, site-specific heme chelators, and molecular genetic approaches, we found here that 1) yeast cells preferentially use LH in heme-depleted conditions; 2) sequestration of cytosolic LH suppresses heme signaling; and 3) lead (Pb2+) stress contributes to a decrease in total heme, but an increase in LH, which correlates with increased heme signaling. We also observed that the proteasome is involved in the regulation of the LH pool and that loss of proteasomal activity sensitizes cells to Pb2+ effects on heme homeostasis. Overall, these findings suggest an important role for LH in supporting heme-dependent functions in yeast physiology.
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Affiliation(s)
| | - Rebecca Hu
- From the School of Chemistry and Biochemistry
| | - Hyojung Kim
- From the School of Chemistry and Biochemistry.,School of Biological Sciences, and
| | | | - Matthew P Torres
- School of Biological Sciences, and.,Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Amit R Reddi
- From the School of Chemistry and Biochemistry, .,Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332
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9
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Heme dynamics and trafficking factors revealed by genetically encoded fluorescent heme sensors. Proc Natl Acad Sci U S A 2016; 113:7539-44. [PMID: 27247412 DOI: 10.1073/pnas.1523802113] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Heme is an essential cofactor and signaling molecule. Heme acquisition by proteins and heme signaling are ultimately reliant on the ability to mobilize labile heme (LH). However, the properties of LH pools, including concentration, oxidation state, distribution, speciation, and dynamics, are poorly understood. Herein, we elucidate the nature and dynamics of LH using genetically encoded ratiometric fluorescent heme sensors in the unicellular eukaryote Saccharomyces cerevisiae We find that the subcellular distribution of LH is heterogeneous; the cytosol maintains LH at ∼20-40 nM, whereas the mitochondria and nucleus maintain it at concentrations below 2.5 nM. Further, we find that the signaling molecule nitric oxide can initiate the rapid mobilization of heme in the cytosol and nucleus from certain thiol-containing factors. We also find that the glycolytic enzyme glyceraldehyde phosphate dehydrogenase constitutes a major cellular heme buffer, and is responsible for maintaining the activity of the heme-dependent nuclear transcription factor heme activator protein (Hap1p). Altogether, we demonstrate that the heme sensors can be used to reveal fundamental aspects of heme trafficking and dynamics and can be used across multiple organisms, including Escherichia coli, yeast, and human cell lines.
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10
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Alberti A, Braga CM, Jaster H, Nogueira A. Dissolved oxygen content in apple must: technological implications in cider processing. JOURNAL OF THE INSTITUTE OF BREWING 2014. [DOI: 10.1002/jib.113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Aline Alberti
- Food Science and Technology Graduate Programme; State University of Ponta Grossa; 4748 Carlos Cavalcanti Av., Uvaranas Campus. CEP 84.030-900 Ponta Grossa PR Brazil
| | - Cíntia Maia Braga
- Food Science and Technology Graduate Programme; State University of Ponta Grossa; 4748 Carlos Cavalcanti Av., Uvaranas Campus. CEP 84.030-900 Ponta Grossa PR Brazil
| | - Henrique Jaster
- Food Science and Technology Graduate Programme; State University of Ponta Grossa; 4748 Carlos Cavalcanti Av., Uvaranas Campus. CEP 84.030-900 Ponta Grossa PR Brazil
| | - Alessandro Nogueira
- Food Science and Technology Graduate Programme; State University of Ponta Grossa; 4748 Carlos Cavalcanti Av., Uvaranas Campus. CEP 84.030-900 Ponta Grossa PR Brazil
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11
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H3K4 methyltransferase Set1 is involved in maintenance of ergosterol homeostasis and resistance to Brefeldin A. Proc Natl Acad Sci U S A 2013; 110:E1016-25. [PMID: 23382196 DOI: 10.1073/pnas.1215768110] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Set1 is a conserved histone H3 lysine 4 (H3K4) methyltransferase that exists as a multisubunit complex. Although H3K4 methylation is located on many actively transcribed genes, few studies have established a direct connection showing that loss of Set1 and H3K4 methylation results in a phenotype caused by disruption of gene expression. In this study, we determined that cells lacking Set1 or Set1 complex members that disrupt H3K4 methylation have a growth defect when grown in the presence of the antifungal drug Brefeldin A (BFA), indicating that H3K4 methylation is needed for BFA resistance. To determine the role of Set1 in BFA resistance, we discovered that Set1 is important for the expression of genes in the ergosterol biosynthetic pathway, including the rate-limiting enzyme HMG-CoA reductase. Consequently, deletion of SET1 leads to a reduction in HMG-CoA reductase protein and total cellular ergosterol. In addition, the lack of Set1 results in an increase in the expression of DAN1 and PDR11, two genes involved in ergosterol uptake. The increase in expression of uptake genes in set1Δ cells allows sterols such as cholesterol and ergosterol to be actively taken up under aerobic conditions. Interestingly, when grown in the presence of ergosterol set1Δ cells become resistant to BFA, indicating that proper ergosterol levels are needed for antifungal drug resistance. These data show that H3K4 methylation impacts gene expression and output of a biologically and medically relevant pathway and determines why cells lacking H3K4 methylation have antifungal drug sensitivity.
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12
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Mauersberger S, Novikova LA, Shkumatov VM. Cytochrome P450 Expression in Yarrowia lipolytica and Its Use in Steroid Biotransformation. YARROWIA LIPOLYTICA 2013. [DOI: 10.1007/978-3-642-38583-4_7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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13
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Effect of lipid supplementation upon Saccharomyces cerevisiae lipid composition and fermentation performance at low temperature. Eur Food Res Technol 2009. [DOI: 10.1007/s00217-008-0996-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Desfougères T, Ferreira T, Bergès T, Régnacq M. SFH2 regulates fatty acid synthase activity in the yeast Saccharomyces cerevisiae and is critical to prevent saturated fatty acid accumulation in response to haem and oleic acid depletion. Biochem J 2007; 409:299-309. [PMID: 17803462 DOI: 10.1042/bj20071028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The yeast Saccharomyces cerevisiae is a facultative anaerobic organism. Under anaerobiosis, sustained growth relies on the presence of exogenously supplied unsaturated fatty acids and ergosterol that yeast is unable to synthesize in the absence of oxygen or upon haem depletion. In the absence of exogenous supplementation with unsaturated fatty acid, a net accumulation of SFA (saturated fatty acid) is observed that induces significant modification of phospholipid profile [Ferreira, Régnacq, Alimardani, Moreau-Vauzelle and Bergès (2004) Biochem. J. 378, 899–908]. In the present paper, we focus on the role of SFH2/CSR1, a hypoxic gene related to SEC14 and its involvement in lipid metabolism upon haem depletion in the absence of oleic acid supplementation. We observed that inactivation of SFH2 results in enhanced accumulation of SFA and phospholipid metabolism alterations. It results in premature growth arrest and leads to an exacerbated sensitivity to exogenous SFA. This phenotype is suppressed in the presence of exogenous oleic acid, or by a controlled expression of FAS1, one of the two genes encoding FAS. We present several lines of evidence to suggest that Sfh2p and oleic acid regulate SFA synthase in yeast at different levels: whereas oleic acid acts on FAS2 at the transcriptional level, we show that Sfh2p inhibits fatty acid synthase activity in response to haem depletion.
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Affiliation(s)
- Thomas Desfougères
- Laboratoire de Génétique de la Levure CNRS-UMR6161, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France
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15
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Schulz TA, Prinz WA. Sterol transport in yeast and the oxysterol binding protein homologue (OSH) family. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:769-80. [PMID: 17434796 PMCID: PMC2034499 DOI: 10.1016/j.bbalip.2007.03.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Revised: 03/06/2007] [Accepted: 03/07/2007] [Indexed: 12/12/2022]
Abstract
Sterols such as cholesterol are a significant component of eukaryotic cellular membranes, and their unique physical properties influence a wide variety of membrane processes. It is known that the concentration of sterol within the membrane varies widely between organelles, and that the cell actively maintains this distribution through various transport processes. Vesicular pathways such as secretion or endocytosis may account for this traffic, but increasing evidence highlights the importance of nonvesicular routes as well. The structure of an oxysterol-binding protein homologue (OSH) in yeast (Osh4p/Kes1p) has recently been solved, identifying it as a sterol binding protein, and there is evidence consistent with the role of a cytoplasmic, nonvesicular sterol transporter. Yeast have seven such proteins, which appear to have distinct but overlapping functions with regard to maintaining intracellular sterol distribution and homeostasis. Control of sterol distribution can have far-reaching effects on membrane-related functions, and Osh proteins have been implicated in a variety of processes such as secretory vesicle budding from the Golgi and establishment of cell polarity. This review summarizes the current body of knowledge regarding this family and its potential functions, placing it in the context of known and hypothesized pathways of sterol transport in yeast.
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Affiliation(s)
- Timothy A Schulz
- Laboratory of Cell Biochemistry and Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, US Department of Health and Human Services, Bethesda, MD 20892, USA
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16
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Ishtar Snoek IS, Yde Steensma H. Factors involved in anaerobic growth ofSaccharomyces cerevisiae. Yeast 2007; 24:1-10. [PMID: 17192845 DOI: 10.1002/yea.1430] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Life in the absence of molecular oxygen requires several adaptations. Traditionally, the switch from respiratory metabolism to fermentation has attracted much attention in Saccharomyces cerevisiae, as this is the basis for the use of this yeast in the production of alcohol and in baking. It has also been clear that under anaerobic conditions the yeast is not able to synthesize sterols and unsaturated fatty acids and that for anaerobic growth these have to be added to the media. More recently it has been found that many more factors play a role. Several other biosynthetic reactions also require molecular oxygen and the yeast must have alternatives for these. In addition, the composition of the cell wall and cell membrane show major differences when aerobic and anaerobic cells are compared. All these changes are reflected by the observation that the transcription of more than 500 genes changes significantly between aerobically and anaerobically growing cultures. In this review we will give an overview of the factors that play a role in the survival in the absence of molecular oxygen.
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Affiliation(s)
- I S Ishtar Snoek
- Institute of Biology, Leiden University, Leiden, The Netherlands.
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Snoek ISI, Steensma HY. Why doesKluyveromyces lactisnot grow under anaerobic conditions? Comparison of essential anaerobic genes ofSaccharomyces cerevisiaewith theKluyveromyces lactisgenome. FEMS Yeast Res 2006; 6:393-403. [PMID: 16630279 DOI: 10.1111/j.1567-1364.2005.00007.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Although some yeast species, e.g. Saccharomyces cerevisiae, can grow under anaerobic conditions, Kluyveromyces lactis cannot. In a systematic study, we have determined which S. cerevisiae genes are required for growth without oxygen. This has been done by using the yeast deletion library. Both aerobically essential and nonessential genes have been tested for their necessity for anaerobic growth. Upon comparison of the K. lactis genome with the genes found to be anaerobically important in S. cerevisiae, which yielded 20 genes that are missing in K. lactis, we hypothesize that lack of import of sterols might be one of the more important reasons that K. lactis cannot grow in the absence of oxygen.
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Affiliation(s)
- I S Ishtar Snoek
- Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
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18
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Deytieux C, Mussard L, Biron MJ, Salmon JM. Fine measurement of ergosterol requirements for growth of Saccharomyces cerevisiae during alcoholic fermentation. Appl Microbiol Biotechnol 2005; 68:266-71. [PMID: 15666147 DOI: 10.1007/s00253-004-1872-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Revised: 12/03/2004] [Accepted: 12/03/2004] [Indexed: 10/25/2022]
Abstract
Yeasts can incorporate a wide variety of exogenous sterols under strict anaerobiosis. Yeasts normally require oxygen for growth when exogenous sterols are limiting, as this favours the synthesis of lipids (sterols and unsaturated fatty acids). Although much is known about the oxygen requirements of yeasts during anaerobic growth, little is known about their exact sterol requirements in such conditions. We developed a method to determine the amount of ergosterol required for the growth of several yeast strains. We found that pre-cultured yeast strains all contained similar amounts of stored sterols, but exhibited different ergosterol assimilation efficiencies in enological conditions [as measured by the ergosterol concentration required to sustain half the number of generations attributed to ergosterol assimilation (P(50))]. P(50) was correlated with the intensity of sterol synthesis. Active dry yeasts (ADYs) contained less stored sterols than their pre-cultured counterparts and displayed very different ergosterol assimilation efficiencies. We showed that five different batches of the same industrial Saccharomyces cerevisiae ADY exhibited significantly different ergosterol requirements for growth. These differences were mainly attributed to differences in initial sterol reserves. The method described here can therefore be used to quantify indirectly the sterol synthesis abilities of yeast strains and to estimate the size of sterol reserves.
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Affiliation(s)
- Christelle Deytieux
- Equipe Microbiologie et de Technologie des Fermentations, UMR 1083 Sciences pour l'Oenologie, Institut National de la Recherche Agronomique, 34060 Montpellier Cedex 1, France
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19
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Pichler H, Riezman H. Where sterols are required for endocytosis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1666:51-61. [PMID: 15519308 DOI: 10.1016/j.bbamem.2004.05.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Accepted: 05/28/2004] [Indexed: 12/15/2022]
Abstract
Sterols are essential membrane components of eukaryotic cells. Interacting closely with sphingolipids, they provide the membrane surrounding required for membrane sorting and trafficking processes. Altering the amount and/or structure of free sterols leads to defects in endocytic pathways in mammalian cells and yeast. Plasma membrane structures functioning in the internalization step in mammalian cells, caveolae and clathrin-coated pits, are affected by cholesterol depletion. Accumulation of improper plasma membrane sterols prevents hyperphosphorylation of a plasma membrane receptor in yeast. Once internalized, sterols still interact with sphingolipids and are recycled to the plasma membrane to keep an intracellular sterol gradient with the highest amount of free sterols at the cell periphery. Interestingly, cells from patients suffering from sphingolipid storage diseases show high intracellular amounts of free cholesterol. We propose that the balanced interaction of sterols and sphingolipids is responsible for protein recruitment to specialized membrane domains and their functionality in the endocytic pathway.
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Affiliation(s)
- Harald Pichler
- Institute of Molecular Biotechnology, Sciences II, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
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20
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Alimardani P, RéGNACQ M, Moreau-Vauzelle C, Ferreira T, Rossignol T, Blondin B, BERGèS T. SUT1-promoted sterol uptake involves the ABC transporter Aus1 and the mannoprotein Dan1 whose synergistic action is sufficient for this process. Biochem J 2004; 381:195-202. [PMID: 15035656 PMCID: PMC1133777 DOI: 10.1042/bj20040297] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Revised: 03/17/2004] [Accepted: 03/22/2004] [Indexed: 11/17/2022]
Abstract
Efficient sterol influx in the yeast Saccharomyces cerevisiae is restricted to anaerobiosis or to haem deficiency resulting from mutations. Constitutive expression of SUT1, an hypoxic gene encoding a transcriptional regulator, induces sterol uptake in aerobiosis. A genome-wide approach using DNA microarray was used to identify the mediators of SUT1 effects on aerobic sterol uptake. A total of 121 ORFs (open reading frames) were significantly and differentially expressed after SUT1 overexpression, 61 down-regulated and 60 up-regulated. Among these genes, the role of the putative ABC transporter (ATP-binding-cassette transporter) Aus1, and of the cell-wall mannoprotein Dan1, was characterized better. These two genes play an essential role in aerobic sterol uptake, since their deletion compromised the SUT1 effects, but individual overexpression of either of these genes in a wild-type background was not sufficient for this process. However, constitutive co-expression of AUS1 and DAN1 in a wild-type background resulted in sterol influx in aerobiosis. These results suggest that the corresponding proteins may act synergistically in vivo to promote sterol uptake.
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Affiliation(s)
- Parissa Alimardani
- *Laboratoire de Génétique de la Levure, CNRS-UMR 6161, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France
| | - Matthieu RéGNACQ
- *Laboratoire de Génétique de la Levure, CNRS-UMR 6161, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France
| | - Carole Moreau-Vauzelle
- *Laboratoire de Génétique de la Levure, CNRS-UMR 6161, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France
| | - Thierry Ferreira
- *Laboratoire de Génétique de la Levure, CNRS-UMR 6161, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France
| | - Tristan Rossignol
- †Laboratoire de Microbiologie et Technologie des Fermentations, UMR Sciences Pour l'œnologie-Institut National de la Recherche Agronomique, 2 Place Viala, 34060 Montpellier Cedex 2, France
| | - Bruno Blondin
- †Laboratoire de Microbiologie et Technologie des Fermentations, UMR Sciences Pour l'œnologie-Institut National de la Recherche Agronomique, 2 Place Viala, 34060 Montpellier Cedex 2, France
| | - Thierry BERGèS
- *Laboratoire de Génétique de la Levure, CNRS-UMR 6161, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France
- To whom correspondence should be addressed (e-mail )
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21
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Hronská L, Mrózová Z, ValachoviÄ M, Hapala I. Low concentrations of the non-ionic detergent Nonidet P-40 interfere with sterol biogenesis and viability of the yeastSaccharomyces cerevisiae. FEMS Microbiol Lett 2004. [DOI: 10.1111/j.1574-6968.2004.tb09762.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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22
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Ferreira T, Régnacq M, Alimardani P, Moreau-Vauzelle C, Bergès T. Lipid dynamics in yeast under haem-induced unsaturated fatty acid and/or sterol depletion. Biochem J 2004; 378:899-908. [PMID: 14640980 PMCID: PMC1224003 DOI: 10.1042/bj20031064] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2003] [Revised: 11/28/2003] [Accepted: 12/01/2003] [Indexed: 11/17/2022]
Abstract
In the yeast Saccharomyces cerevisiae, UFA (unsaturated fatty acids) and ergosterol syntheses are aerobic processes that require haem. We took advantage of a strain affected in haem synthesis ( hem1 Delta) to starve specifically for one or the other of these essential lipids in order to examine the consequences on the overall lipid composition. Our results demonstrate that reserve lipids (i.e. triacylglycerols and steryl esters) are depleted independently of haem availability and that their UFA and sterol content is not crucial to sustain residual growth under lipid depletion. In parallel to UFA starvation, a net accumulation of SFA (saturated fatty acids) is observed as a consequence of haem biosynthesis preclusion. Interestingly, the excess SFA are not mainly stored within triacylglycerols and steryl esters but rather within specific phospholipid species, with a marked preference for PtdIns. This results in an increase in the cellular PtdIns content. However, neutral lipid homoeostasis is perturbed under haem starvation. The contribution of two lipid particle-associated proteins (namely Tgl1p and Dga1p) to this process is described.
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Affiliation(s)
- Thierry Ferreira
- Laboratoire de Génétique de la Levure, CNRS-UMR6161, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers CEDEX, France
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23
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Psomas EI, Fletouris DJ, Litopoulou-Tzanetaki E, Tzanetakis N. Assimilation of cholesterol by yeast strains isolated from infant feces and Feta cheese. J Dairy Sci 2004; 86:3416-22. [PMID: 14672170 DOI: 10.3168/jds.s0022-0302(03)73945-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Eight yeast strains isolated from infant feces and the traditional Greek Feta cheese, selected for their probiotic properties, were tested along with a commercially available strain of Saccharomyces boulardii for their ability to remove cholesterol from a growth medium (yeast extract glucose peptone broth) supplemented with 0.3% Oxgall. The amount of cholesterol removed during 72 h of growth at 37 degrees C revealed significant variations among the yeast strains examined. Two isolates from infant feces, namely Saccharomyces cerevisiae KK1 and Isaatchenkia orientalis KK5.Y.1 and one isolate from Feta cheese, namely S. cerevisiae 832, along with the commercial strain S. boulardii, were able to remove cholesterol from the growth medium after 48 h of incubation at 37 degrees C. However, Saccharomyces strains proved to be able to remove cholesterol even after 24 h of growth at 37 degrees C. The cholesterol removed from the growth medium was not metabolically degraded but was rather assimilated into the yeast cells. The ability to assimilate cholesterol in vitro and to tolerate low pH levels, gastric juice, and bile indicate that S. cerevisiae 832, and especially S. cerevisiae KK1 and I. orientalis KK5.Y.1 (being more bile and gastric juice tolerant because of their human origin) may be promising candidate strains for use as probiotics.
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Affiliation(s)
- E I Psomas
- Laboratory of Food Microbiology and Hygiene, Faculty of Agriculture, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece.
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24
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Rosenfeld E, Beauvoit B. Role of the non-respiratory pathways in the utilization of molecular oxygen by Saccharomyces cerevisiae. Yeast 2004; 20:1115-44. [PMID: 14558145 DOI: 10.1002/yea.1026] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Saccharomyces cerevisiae is a facultative anaerobe devoid of mitochondrial alternative oxidase. In this yeast, the structure and biogenesis of the respiratory chain, on the one hand, and the functional interactions of oxidative phosphorylation with the cellular energetic metabolism, on the other, are well documented. However, to our knowledge, the molecular aspects and the physiological roles of the non-respiratory pathways that utilize molecular oxygen have not yet been reviewed. In this paper, we review the various non-respiratory pathways in a global context of utilization of molecular oxygen in S. cerevisiae. The roles of these pathways are examined as a function of environmental conditions, using either physiological, biochemical or molecular data. Special attention is paid to the characterization of the so-called 'cyanide-resistant respiration' that is induced by respiratory deficiency, catabolic repression and oxygen limitation during growth. Finally, several aspects of oxygen sensing are discussed.
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Affiliation(s)
- Eric Rosenfeld
- Laboratoire de Génie Protéique et Cellulaire, Bâtiment Marie Curie, Pôle Sciences et Technologies, Université de La Rochelle, Avenue Michel Crépeau, 17042 La Rochelle Cedex 1, France.
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25
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Ness F, Bourot S, Régnacq M, Spagnoli R, Bergès T, Karst F. SUT1 is a putative Zn[II]2Cys6-transcription factor whose upregulation enhances both sterol uptake and synthesis in aerobically growingSaccharomyces cerevisiaecells. ACTA ACUST UNITED AC 2003. [DOI: 10.1046/j.1432-1327.2001.02029.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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Ter Linde JJM, Régnacq M, Steensma HY. Transcriptional regulation of YML083c under aerobic and anaerobic conditions. Yeast 2003; 20:439-54. [PMID: 12673627 DOI: 10.1002/yea.975] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
YML083c and DAN1 were among the Saccharomyces cerevisiae ORFs that displayed the strongest increase in transcript abundance during anaerobic growth compared to aerobic growth, as determined by oligonucleotide microarrays. We here report that transcription of YML083c is regulated by at least three different factors. First, repression under aerobic conditions depends on the presence of heme. Second, deletion analysis of the 5'-flanking region of YML083c and DAN1 revealed two regions responsible for anaerobic induction. Each of these regions conferred anoxia-regulated expression to the heterologous, minimal, CYC1-lacZ reporter. Mutations in the AAACGA subelement, common to the positive acting regions of YML083c and DAN1, almost completely abolished the ability to drive anaerobic expression of the reporter gene. This subelement is similar to the AR1 site, which is involved in anaerobic induction of the DAN/TIR genes. Activation through the AR1 site depends on Upc2. Indeed, transcription from the YML083c promoter was decreased in an upc2 null mutant. Third, expression of Sut1 under aerobic conditions enhanced transcription of YML083c, suggesting that aerobic repression of YML083c is promoted by the general Tup1-Ssn6 co-repressor complex. However, despite the presence of a sequence that matches the consensus for binding of Rox1, YML083c is not controlled by Rox1, since deletion or replacement of the putative binding site did not cause aerobic derepression. Moreover, YML083c expression was undetectable in aerobically grown cells of a rox1 null mutant.
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Affiliation(s)
- J J M Ter Linde
- Institute of Molecular Plant Sciences, Leiden University, Wassenaarseweg 64, 2333 AL, Leiden, The Netherlands
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27
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Duport C, Schoepp B, Chatelain E, Spagnoli R, Dumas B, Pompon D. Critical role of the plasma membrane for expression of mammalian mitochondrial side chain cleavage activity in yeast. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:1502-14. [PMID: 12654006 DOI: 10.1046/j.1432-1033.2003.03516.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Engineered yeast cells efficiently convert ergosta-5-eneol to pregnenolone and progesterone provided that endogenous pregnenolone acetylase activity is disrupted and that heterologous sterol delta7-reductase, cytochrome P450 side chain cleavage (CYP11A1) and 3beta hydroxysteroid dehydrogenase/isomerase (3beta-HSD) activities are present. CYP11A1 activity requires the expression of the mammalian NADPH-adrenodoxin reductase (Adrp) and adrenodoxin (Adxp) proteins as electron carriers. Several parameters modulate this artificial metabolic pathway: the effects of steroid products; the availability and delivery of the ergosta-5-eneol substrate to cytochrome P450; electron flux and protein localization. CYP11A1, Adxp and Adrp are usually located in contact with inner mitochondrial membranes and are directed to the outside of the mitochondria by the removal of their respective mitochondrial targeting sequences. CYP11A1 then localizes to the plasma membrane but Adrp and Adxp are detected in the endoplasmic reticulum and cytosol as expected. The electron transfer chain that involves several subcellular compartments may control side chain cleavage activity in yeast. Interestingly, Tgl1p, a potential ester hydrolase, was found to enhance steroid productivity, probably through both the availability and/or the trafficking of the CYP11A1 substrate. Thus, the observation that the highest cellular levels of free ergosta-5-eneol are found in the plasma membrane suggests that the substrate is freely available for pregnenolone synthesis.
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Affiliation(s)
- Catherine Duport
- Laboratoire d'Ingénierie des Protéines Membranaires, CGM du CNRS, Gif sur Yvette, France
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28
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Rosenfeld E, Beauvoit B, Blondin B, Salmon JM. Oxygen consumption by anaerobic Saccharomyces cerevisiae under enological conditions: effect on fermentation kinetics. Appl Environ Microbiol 2003; 69:113-21. [PMID: 12513985 PMCID: PMC152411 DOI: 10.1128/aem.69.1.113-121.2003] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The anaerobic growth of the yeast Saccharomyces cerevisiae normally requires the addition of molecular oxygen, which is used to synthesize sterols and unsaturated fatty acids (UFAs). A single oxygen pulse can stimulate enological fermentation, but the biochemical pathways involved in this phenomenon remain to be elucidated. We showed that the addition of oxygen (0.3 to 1.5 mg/g [dry mass] of yeast) to a lipid-depleted medium mainly resulted in the synthesis of the sterols and UFAs required for cell growth. However, the addition of oxygen during the stationary phase in a medium containing excess ergosterol and oleic acid increased the specific fermentation rate, increased cell viability, and shortened the fermentation period. Neither the respiratory chain nor de novo protein synthesis was required for these medium- and long-term effects. As de novo lipid synthesis may be involved in ethanol tolerance, we studied the effect of oxygen addition on sterol and UFA auxotrophs (erg1 and ole1 mutants, respectively). Both mutants exhibited normal anaerobic fermentation kinetics. However, only the ole1 mutant strain responded to the oxygen pulse during the stationary phase, suggesting that de novo sterol synthesis is required for the oxygen-induced increase of the specific fermentation rate. In conclusion, the sterol pathway appears to contribute significantly to the oxygen consumption capacities of cells under anaerobic conditions. Nevertheless, we demonstrated the existence of alternative oxygen consumption pathways that are neither linked to the respiratory chain nor linked to heme, sterol, or UFA synthesis. These pathways dissipate the oxygen added during the stationary phase, without affecting the fermentation kinetics.
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Affiliation(s)
- Eric Rosenfeld
- Laboratoire de Microbiologie et de Technologie des Fermentations, Unité Mixte de Recherches Sciences pour l'oenologie, Institut National de la Recherche Agronomique, F-34060 Montpellier Cedex 1, France
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29
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Rosenfeld E, Beauvoit B, Rigoulet M, Salmon JM. Non-respiratory oxygen consumption pathways in anaerobically-grown Saccharomyces cerevisiae: evidence and partial characterization. Yeast 2002; 19:1299-321. [PMID: 12402241 DOI: 10.1002/yea.918] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Despite the absence of an alternative mitochondrial ubiquinol oxidase, Saccharomyces cerevisiae consumes oxygen in an antimycin A- and cyanide-resistant manner. Cyanide-resistant respiration is typically used when the classical respiratory chain is impaired or absent (i.e in anaerobically-grown cells shifted to normoxia or in respiratory-deficient cells). We characterized the non-respiratory oxygen consumption pathways operating during anoxic-normoxic transitions in glucose-repressed resting cells. High-resolution oxygraphy confirmed that the cellular non-respiratory oxygen consumption pathway is sensitive to high concentrations of cyanide, azide, SHAM and TTFA, and revealed several new characteristics. First, the use of sterol biosynthesis inhibitors showed that this pathway makes a considerable contribution (about 25%) to both endogenous and glucose-dependent oxygen consumption. Anaerobically-grown glucose-repressed cells exhibited high apparent oxygen affinities (K(m) for oxygen = 0.5-1 micro M), even in mutants deficient in respiration or sterol synthesis. Exogeneously added glucose and endogenous stored carbohydrates were the only substrates that were efficient for cellular oxygen consumption (apparent K(m) for exogenous glucose = 2-3 mM). On the other hand, fluorimetric measurements of the cellular NAD(P)H pool showed that the cellular oxygen consumption (sterol biosynthesis and unknown pathways) was dependent more on the intracellular level of NADPH than of NADH. High oxygen affinity NADPH-dependent oxygen consumption systems were thought to be mainly localized in microsomal membranes, and several data indicated a significant contribution made by uncoupled p450 systems, together with still uncharacterized systems. Such activities are associated in vitro with a massive production of O(2) (.-) and, to a lower extent, H(2)O(2) and a likely concomitant production of H(2)O.
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Affiliation(s)
- Eric Rosenfeld
- Laboratoire de Microbiologie et de Technologie des Fermentations, Unité Mixte de Recherches 'Sciences pour l'OEnologie', Institut National de la Recherche Agronomique, 2 Place Viala, 34060 Montpellier Cedex 1, France
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30
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Vico P, Cauet G, Rose K, Lathe R, Degryse E. Dehydroepiandrosterone (DHEA) metabolism in Saccharomyces cerevisiae expressing mammalian steroid hydroxylase CYP7B: Ayr1p and Fox2p display 17beta-hydroxysteroid dehydrogenase activity. Yeast 2002; 19:873-86. [PMID: 12112241 DOI: 10.1002/yea.882] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We have engineered recombinant yeast to perform stereospecific hydroxylation of dehydroepiandrosterone (DHEA). This mammalian pro-hormone promotes brain and immune function; hydroxylation at the 7alpha position by P450 CYP7B is the major pathway of metabolic activation. We have sought to activate DHEA via yeast expression of rat CYP7B enzyme. Saccharomyces cerevisiae was found to metabolize DHEA by 3beta-acetylation; this was abolished by mutation at atf2. DHEA was also toxic, blocking tryptophan (trp) uptake: prototrophic strains were DHEA-resistant. In TRP(+) atf2 strains DHEA was then converted to androstene-3beta,17beta-diol (A/enediol) by an endogenous 17beta-hydroxysteroid dehydrogenase (17betaHSD). Seven yeast polypeptides similar to human 17betaHSDs were identified: when expressed in yeast, only AYR1 (1-acyl dihydroxyacetone phosphate reductase) increased A/enediol accumulation, while the hydroxyacyl-CoA dehydrogenase Fox2p, highly homologous to human 17betaHSD4, oxidized A/enediol to DHEA. The presence of endogenous yeast enzymes metabolizing steroids may relate to fungal pathogenesis. Disruption of AYR1 eliminated reductive 17betaHSD activity, and expression of CYP7B on the combination background (atf2, ayr1, TRP(+)) permitted efficient (>98%) bioconversion of DHEA to 7alpha-hydroxyDHEA, a product of potential medical utility.
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Affiliation(s)
- Pedro Vico
- Transgene SA, 11 Rue de Molsheim, 67000 Strasbourg, France.
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31
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Régnacq M, Alimardani P, El Moudni B, Bergès T. SUT1p interaction with Cyc8p(Ssn6p) relieves hypoxic genes from Cyc8p-Tup1p repression in Saccharomyces cerevisiae. Mol Microbiol 2001; 40:1085-96. [PMID: 11401714 DOI: 10.1046/j.1365-2958.2001.02450.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUT1 is a hypoxic gene encoding a nuclear protein that belongs to the Zn[II]2Cys-6 family. It has been shown that constitutive expression of SUT1 induces exogenous sterol uptake in aerobically growing Saccharomyces cerevisiae cells. A differential display approach was used to identify genes whose transcription is modified upon SUT1 induction. Within the promoter sequence of one of these genes, DAN1, we identified the region responsive to SUT1 and showed that it has a strong repressive activity when cloned in the vicinity of distinct promoters. Upon SUT1 constitutive expression in aerobiosis, the repression is released, allowing enhanced transcription of the reporter gene. We provide evidence that the repression is promoted by the Cyc8p(Ssn6p)-Tup1p co-repressor and that release of repression is the result of a physical interaction between Sut1p and Cyc8p. Moreover, genetic data suggest that complete derepression of the reporter gene requires a functional Cyc8p. In addition, we show that Sut1p is involved in the induction of hypoxic gene transcription when the cells are shifted from aerobiosis to anaerobiosis.
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Affiliation(s)
- M Régnacq
- Université de Poitiers, Faculté des Sciences, Laboratoire de Génétique de la Levure, UMR 6161, IBMIG, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex, France
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32
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Soustre I, Dupuy PH, Silve S, Karst F, Loison G. Sterol metabolism and ERG2 gene regulation in the yeast Saccharomyces cerevisiae. FEBS Lett 2000; 470:102-6. [PMID: 10734216 DOI: 10.1016/s0014-5793(00)01300-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Certain exogenously-supplied sterols, like ergost-8-enol, are efficiently converted into ergosterol in yeast. We have taken advantage of this property to study the regulation of the Delta8-Delta7-sterol isomerase-encoding ERG2 gene in an ergosterol auxotrophic mutant devoid of squalene-synthase activity. Ergosterol starvation leads to an 8-16-fold increase in ERG2 gene expression. Such an increase was also observed in wild-type cells either grown anaerobically or treated with SR31747A a sterol isomerase inhibitor. Exogenously-supplied zymosterol is entirely transformed into ergosterol, which represses ERG2 transcription. By contrast, exogenously-supplied ergosterol has little or no effect on ERG2 transcription.
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MESH Headings
- Anaerobiosis
- Biological Transport
- Cholesterol/metabolism
- Cholesterol/pharmacology
- Cyclohexanes/pharmacology
- Ergosterol/analogs & derivatives
- Ergosterol/biosynthesis
- Ergosterol/metabolism
- Ergosterol/pharmacology
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Fungal/drug effects
- Genes, Fungal/genetics
- Genes, Fungal/physiology
- Genes, Reporter/genetics
- Lanosterol/metabolism
- Lanosterol/pharmacology
- Morpholines/pharmacology
- Mutation/genetics
- Oxygen/metabolism
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Saccharomyces cerevisiae/drug effects
- Saccharomyces cerevisiae/enzymology
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Steroid Isomerases/antagonists & inhibitors
- Steroid Isomerases/genetics
- Sterols/metabolism
- Sterols/pharmacology
- Transcription, Genetic/drug effects
- Transcription, Genetic/genetics
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Affiliation(s)
- I Soustre
- Université Louis Pasteur, INRA, 28, rue de Herrlisheim, P.O. Box 507, 68021, Colmar, France
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Warnecke D, Erdmann R, Fahl A, Hube B, Müller F, Zank T, Zähringer U, Heinz E. Cloning and functional expression of UGT genes encoding sterol glucosyltransferases from Saccharomyces cerevisiae, Candida albicans, Pichia pastoris, and Dictyostelium discoideum. J Biol Chem 1999; 274:13048-59. [PMID: 10224056 DOI: 10.1074/jbc.274.19.13048] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sterol glucosides, typical membrane-bound lipids of many eukaryotes, are biosynthesized by a UDP-glucose:sterol glucosyltransferase (EC 2. 4.1.173). We cloned genes from three different yeasts and from Dictyostelium discoideum, the deduced amino acid sequences of which all showed similarities with plant sterol glucosyltransferases (Ugt80A1, Ugt80A2). These genes from Saccharomyces cerevisiae (UGT51 = YLR189C), Pichia pastoris (UGT51B1), Candida albicans (UGT51C1), and Dictyostelium discoideum (ugt52) were expressed in Escherichia coli. In vitro enzyme assays with cell-free extracts of the transgenic E. coli strains showed that the genes encode UDP-glucose:sterol glucosyltransferases which can use different sterols such as cholesterol, sitosterol, and ergosterol as sugar acceptors. An S. cerevisiae null mutant of UGT51 had lost its ability to synthesize sterol glucoside but exhibited normal growth under various culture conditions. Expression of either UGT51 or UGT51B1 in this null mutant under the control of a galactose-induced promoter restored sterol glucoside synthesis in vitro. Lipid extracts of these cells contained a novel glycolipid. This lipid was purified and identified as ergosterol-beta-D-glucopyranoside by nuclear magnetic resonance spectroscopy. These data prove that the cloned genes encode sterol-beta-D-glucosyltransferases and that sterol glucoside synthesis is an inherent feature of eukaryotic microorganisms.
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Affiliation(s)
- D Warnecke
- Universität Hamburg, Institut für Allgemeine Botanik, 22609 Hamburg, Germany.
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Leak FW, Tove S, Parks LW. In yeast, upc2-1 confers a decrease in tolerance to LiCl and NaCl, which can be suppressed by the P-type ATPase encoded by ENA2. DNA Cell Biol 1999; 18:133-9. [PMID: 10073572 DOI: 10.1089/104454999315510] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Wild-type yeast cells are unable to take up sterols from their growth media under aerobic conditions and are relatively resistant to monovalent cations. A yeast mutant (upc2-1) with a defect in the aerobic exclusion of sterols was found to have increased sensitivity to LiCl and NaCl. Although cation sensitivity has been reported for mutants that synthesize altered sterols, the mutant with upc2-1 continues to produce the normal sterol, ergosterol. The ENA2 gene was cloned on the basis of remediating the hypersensitivity to the monovalent cations.
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Affiliation(s)
- F W Leak
- Department of Microbiology, North Carolina State University, Raleigh 27695-7615, USA
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