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Potassium and Sodium Salt Stress Characterization in the Yeasts Saccharomyces cerevisiae, Kluyveromyces marxianus, and Rhodotorula toruloides. Appl Environ Microbiol 2021; 87:e0310020. [PMID: 33893111 DOI: 10.1128/aem.03100-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biotechnology requires efficient microbial cell factories. The budding yeast Saccharomyces cerevisiae is a vital cell factory, but more diverse cell factories are essential for the sustainable use of natural resources. Here, we benchmarked nonconventional yeasts Kluyveromyces marxianus and Rhodotorula toruloides against S. cerevisiae strains CEN.PK and W303 for their responses to potassium and sodium salt stress. We found an inverse relationship between the maximum growth rate and the median cell volume that was responsive to salt stress. The supplementation of K+ to CEN.PK cultures reduced Na+ toxicity and increased the specific growth rate 4-fold. The higher K+ and Na+ concentrations impaired ethanol and acetate metabolism in CEN.PK and acetate metabolism in W303. In R. toruloides cultures, these salt supplementations induced a trade-off between glucose utilization and cellular aggregate formation. Their combined use increased the beta-carotene yield by 60% compared with that of the reference. Neural network-based image analysis of exponential-phase cultures showed that the vacuole-to-cell volume ratio increased with increased cell volume for W303 and K. marxianus but not for CEN.PK and R. toruloides in response to salt stress. Our results provide insights into common salt stress responses in yeasts and will help design efficient bioprocesses. IMPORTANCE Characterization of microbial cell factories under industrially relevant conditions is crucial for designing efficient bioprocesses. Salt stress, typical in industrial bioprocesses, impinges upon cell volume and affects productivity. This study presents an open-source neural network-based analysis method to evaluate volumetric changes using yeast optical microscopy images. It allows quantification of cell and vacuole volumes relevant to cellular physiology. On applying salt stress in yeasts, we found that the combined use of K+ and Na+ improves the cellular fitness of Saccharomyces cerevisiae strain CEN.PK and increases the beta-carotene productivity in Rhodotorula toruloides, a commercially important antioxidant and a valuable additive in foods.
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52
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Yang X, Yang Y, Huang J, Man D, Guo M. Comparisons of urea or ammonium on growth and fermentative metabolism of Saccharomyces cerevisiae in ethanol fermentation. World J Microbiol Biotechnol 2021; 37:98. [PMID: 33969436 DOI: 10.1007/s11274-021-03056-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 04/13/2021] [Indexed: 10/21/2022]
Abstract
This work was mainly about the understanding of how urea and ammonium affect growth, glucose consumption and ethanol production of S. cerevisiae, in particular regarding the basic physiology of cell. The basic physiology of cell included intracellular pH, ATP, NADH and enzyme activity. Results showed that fermentation time was reduced by 19% when using urea compared with ammonium. The maximal ethanol production rate using urea was 1.14 g/L/h, increasing 30% comparing with the medium prepared with ammonium. Moreover, urea could decrease the synthesis of glycerol from glucose by 26% comparing with ammonium. The by-product of acetic acid yields decreased from 40 mmol/mol of glucose (with urea) to 24 mmol/mol of glucose (with ammonium). At the end of ethanol fermentation, cell number and pH were greater with urea than ammonium. Comparing with urea, ammonium decreased the intracellular pH by 14% (from 7.1 to 6.1). Urease converting urea into ammonia resulted in a more than 50% lower of ATP when comparing with ammonium. The values of NADH/DCW were 0.21 mg/g and 0.14 mg/g respectively with urea and ammonium, suggesting a 33% lower NADH. The enzyme activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was 0.0225 and 0.0275 U/mg protein respectively with urea and ammonium, which was consistent with the yields of glycerol.
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Affiliation(s)
- Xinchao Yang
- School of Biological Science and Technology, University of Jinan, Jinan, 250022, China.
| | - Yuling Yang
- Linghua Group Limited, Jining, 272073, China
| | - Jiadong Huang
- School of Biological Science and Technology, University of Jinan, Jinan, 250022, China
| | - Deen Man
- Linghua Group Limited, Jining, 272073, China
| | - Maihai Guo
- Linghua Group Limited, Jining, 272073, China
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53
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β-Naphthothiazolium-based ratiometric fluorescent probe with ideal pKa for pH imaging in mitochondria of living cells. Talanta 2021; 232:122475. [PMID: 34074443 DOI: 10.1016/j.talanta.2021.122475] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 04/23/2021] [Accepted: 04/25/2021] [Indexed: 11/21/2022]
Abstract
The weakly alkaline microenvironment (pH ~8.0) in mitochondria plays a vital role in maintaining its morphology and function. Thus monitoring mitochondrial pH (pHmito) is of great significance. Herein, a ratiometric fluorescent probe (ENBT) for pHmito imaging in mitochondria of living cells is reported. pH variation closely correlates to intramolecular charge transfer (ICT) from naphthol to β-naphthothiazolium. ENBT exhibits a remarkable decrease on ratiometric fluorescence at λem1/λem2 = F595/F700 in response to pH variation within 6.30-9.29. In addition, ENBT has an ideal pKa value of 7.94 ± 0.08, which is advantageous in accurate sensing of pHmito. Moreover, ENBT has a Stokes shift of >150 nm, which effectively eliminates the potential interference from the excitation irradiation. ENBT shows excellent capability for specific staining of mitochondria with low cytotoxicity, which is most suitable for pHmito imaging in live cells. The probe was applied for monitoring pHmito variation in mitochondria of live cells caused by H2O2, NAC (N-Acetyl-l-cysteine), NH4Cl, carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and lactate/pyruvate. The morphological alterations of mitochondria in living cells after treatment by CCCP were further evaluated.
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54
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Kato K, Nakayoshi T, Kurimoto E, Oda A. Modification of the pH Dependence of Assembly of Yeast Cargo Receptor Emp47p Coiled-Coil Domains: Computational Design and Experimental Mutagenesis. J Phys Chem B 2021; 125:2222-2230. [PMID: 33646773 DOI: 10.1021/acs.jpcb.0c10194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The coiled-coil domains of the putative yeast cargo receptors Emp46p and Emp47p (Emp46pcc and Emp47pcc) assemble into heterocomplexes at neutral pH. Upon lowering the pH, the complex dissociates and reassembles into homo-oligomers. A glutamate residue (E303) located on the hydrophobic surface of Emp46pcc serves as the pH-sensing switch for assembly and segregation, and we have suggested that its side chains are protonated in the heterocomplex, even at neutral pH. To examine this hypothesis, we constructed two structural models in which the side chains of E303 were negatively charged or protonated and analyzed the effects of these charged states on the structure of the heterocomplex using molecular dynamics (MD) simulations. The calculated structures suggested the side chains of E303 to be protonated in the heterocomplex, even at neutral pH. Based on these computational results, the pH dependence of Emp47pcc homo-oligomer assembly was experimentally modified by a glutamate mutation on its hydrophobic surface. The Q306E mutant of Emp47pcc underwent a structural transition at physiological pH. Our results suggest a method for modifying pH-dependent protein-protein interactions.
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Affiliation(s)
- Koichi Kato
- College of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyama-ku, Nagoya, Aichi 463-8521, Japan.,Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan
| | - Tomoki Nakayoshi
- Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan
| | - Eiji Kurimoto
- Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan
| | - Akifumi Oda
- Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan.,Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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55
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Yocum HC, Pham A, Da Silva NA. Successful Enzyme Colocalization Strategies in Yeast for Increased Synthesis of Non-native Products. Front Bioeng Biotechnol 2021; 9:606795. [PMID: 33634084 PMCID: PMC7901933 DOI: 10.3389/fbioe.2021.606795] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/11/2021] [Indexed: 11/13/2022] Open
Abstract
Yeast cell factories, particularly Saccharomyces cerevisiae, have proven valuable for the synthesis of non-native compounds, ranging from commodity chemicals to complex natural products. One significant challenge has been ensuring sufficient carbon flux to the desired product. Traditionally, this has been addressed by strategies involving "pushing" and "pulling" the carbon flux toward the products by overexpression while "blocking" competing pathways via downregulation or gene deletion. Colocalization of enzymes is an alternate and complementary metabolic engineering strategy to control flux and increase pathway efficiency toward the synthesis of non-native products. Spatially controlling the pathway enzymes of interest, and thus positioning them in close proximity, increases the likelihood of reaction along that pathway. This mini-review focuses on the recent developments and applications of colocalization strategies, including enzyme scaffolding, construction of synthetic organelles, and organelle targeting, in both S. cerevisiae and non-conventional yeast hosts. Challenges with these techniques and future directions will also be discussed.
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Affiliation(s)
- Hannah C Yocum
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, CA, United States
| | - Anhuy Pham
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, CA, United States
| | - Nancy A Da Silva
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, CA, United States
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56
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Saliba E, Primo C, Guarini N, André B. A plant plasma-membrane H +-ATPase promotes yeast TORC1 activation via its carboxy-terminal tail. Sci Rep 2021; 11:4788. [PMID: 33637787 PMCID: PMC7910539 DOI: 10.1038/s41598-021-83525-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 01/28/2021] [Indexed: 01/05/2023] Open
Abstract
The Target of Rapamycin Complex 1 (TORC1) involved in coordination of cell growth and metabolism is highly conserved among eukaryotes. Yet the signals and mechanisms controlling its activity differ among taxa, according to their biological specificities. A common feature of fungal and plant cells, distinguishing them from animal cells, is that their plasma membrane contains a highly abundant H+-ATPase which establishes an electrochemical H+ gradient driving active nutrient transport. We have previously reported that in yeast, nutrient-uptake-coupled H+ influx elicits transient TORC1 activation and that the plasma-membrane H+-ATPase Pma1 plays an important role in this activation, involving more than just establishment of the H+ gradient. We show here that the PMA2 H+-ATPase from the plant Nicotiana plumbaginifolia can substitute for Pma1 in yeast, to promote H+-elicited TORC1 activation. This H+-ATPase is highly similar to Pma1 but has a longer carboxy-terminal tail binding 14-3-3 proteins. We report that a C-terminally truncated PMA2, which remains fully active, fails to promote H+-elicited TORC1 activation. Activation is also impaired when binding of PMA2 to 14-3-3 s is hindered. Our results show that at least some plant plasma-membrane H+-ATPases share with yeast Pma1 the ability to promote TORC1 activation in yeast upon H+-coupled nutrient uptake.
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Affiliation(s)
- Elie Saliba
- Molecular Physiology of the Cell, Université Libre de Bruxelles (ULB), 6041, Biopark, Gosselies, Belgium
| | - Cecilia Primo
- Molecular Physiology of the Cell, Université Libre de Bruxelles (ULB), 6041, Biopark, Gosselies, Belgium
| | - Nadia Guarini
- Molecular Physiology of the Cell, Université Libre de Bruxelles (ULB), 6041, Biopark, Gosselies, Belgium
| | - Bruno André
- Molecular Physiology of the Cell, Université Libre de Bruxelles (ULB), 6041, Biopark, Gosselies, Belgium.
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57
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Growth Inhibition by Amino Acids in Saccharomyces cerevisiae. Microorganisms 2020; 9:microorganisms9010007. [PMID: 33375077 PMCID: PMC7822121 DOI: 10.3390/microorganisms9010007] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/17/2022] Open
Abstract
Amino acids are essential metabolites but can also be toxic when present at high levels intracellularly. Substrate-induced downregulation of amino acid transporters in Saccharomyces cerevisiae is thought to be a mechanism to avoid this toxicity. It has been shown that unregulated uptake by the general amino acid permease Gap1 causes cells to become sensitive to amino acids. Here, we show that overexpression of eight other amino acid transporters (Agp1, Bap2, Can1, Dip5, Gnp1, Lyp1, Put4, or Tat2) also induces a growth defect when specific single amino acids are present at concentrations of 0.5-5 mM. We can now state that all proteinogenic amino acids, as well as the important metabolite ornithine, are growth inhibitory to S. cerevisiae when transported into the cell at high enough levels. Measurements of initial transport rates and cytosolic pH show that toxicity is due to amino acid accumulation and not to the influx of co-transported protons. The amino acid sensitivity phenotype is a useful tool that reports on the in vivo activity of transporters and has allowed us to identify new transporter-specific substrates.
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58
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Schmidl S, Iancu CV, Reifenrath M, Choe JY, Oreb M. A label-free real-time method for measuring glucose uptake kinetics in yeast. FEMS Yeast Res 2020; 21:6041724. [PMID: 33338229 DOI: 10.1093/femsyr/foaa069] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/16/2020] [Indexed: 01/19/2023] Open
Abstract
Glucose uptake assays commonly rely on the isotope-labeled sugar, which is associated with radioactive waste and exposure of the experimenter to radiation. Here, we show that the rapid decrease of the cytosolic pH after a glucose pulse to starved Saccharomyces cerevisiae cells is dependent on the rate of sugar uptake and can be used to determine the kinetic parameters of sugar transporters. The pH-sensitive green fluorescent protein variant pHluorin is employed as a genetically encoded biosensor to measure the rate of acidification as a proxy of transport velocity in real time. The measurements are performed in the hexose transporter-deficient (hxt0) strain EBY.VW4000 that has been previously used to characterize a plethora of sugar transporters from various organisms. Therefore, this method provides an isotope-free, fluorometric approach for kinetic characterization of hexose transporters in a well-established yeast expression system.
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Affiliation(s)
- Sina Schmidl
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Cristina V Iancu
- Department of Chemistry, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC27834, USA
| | - Mara Reifenrath
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Jun-Yong Choe
- Department of Chemistry, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC27834, USA
| | - Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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59
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Ganeva V, Angelova B, Galutzov B, Goltsev V, Zhiponova M. Extraction of Proteins and Other Intracellular Bioactive Compounds From Baker's Yeasts by Pulsed Electric Field Treatment. Front Bioeng Biotechnol 2020; 8:552335. [PMID: 33384987 PMCID: PMC7770146 DOI: 10.3389/fbioe.2020.552335] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 11/23/2020] [Indexed: 11/13/2022] Open
Abstract
Yeasts are rich source of proteins, antioxidants, vitamins, and other bioactive compounds. The main drawback in their utilization as valuable ingredients in functional foods and dietary supplements production is the thick, indigestible cell wall, as well as the high nucleic acid content. In this study, we evaluated the feasibility of pulsed electric field (PEF) treatment as an alternative method for extraction of proteins and other bioactive intracellular compounds from yeasts. Baker's yeast water suspensions with different concentration (12.5-85 g dry cell weight per liter) were treated with monopolar rectangular pulses using a continuous flow system. The PEF energy required to achieve irreversible electropermeabilization was significantly reduced with the increase of the biomass concentration. Upon incubation of the permeabilized cells in water, only relatively small intracellular compounds were released. Release of 90% of the free amino acids and low molecular UV absorbing compounds, 80% of the glutathione, and ∼40% of the total phenol content was achieved about 2 h after pulsation and incubation of the suspensions at room temperature. At these conditions, the macromolecules (proteins and nucleic acids) were retained largely inside. Efficient protein release (∼90% from the total soluble protein) occurred only after dilution and incubation of the permeabilized cells in buffer with pH 8-9. Protein concentrates obtained by ultrafiltration (10 kDa cut off) had lower nucleic acid content (protein/nucleic acid ratio ∼100/4.5) in comparison with cell lysates obtained by mechanical disintegration. The obtained results allowed to conclude that PEF treatment can be used as an efficient alternative approach for production of yeast extracts with different composition, suitable for application in food, cosmetics and pharmaceutical industries.
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Affiliation(s)
- Valentina Ganeva
- Biological Faculty, Sofia University “St. Kl. Ohridski”, Sofia, Bulgaria
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60
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Jia H, Chen T, Qu J, Yao M, Xiao W, Wang Y, Li C, Yuan Y. Collaborative subcellular compartmentalization to improve GPP utilization and boost sabinene accumulation in Saccharomyces cerevisiae. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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61
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Kostyuk AI, Panova AS, Kokova AD, Kotova DA, Maltsev DI, Podgorny OV, Belousov VV, Bilan DS. In Vivo Imaging with Genetically Encoded Redox Biosensors. Int J Mol Sci 2020; 21:E8164. [PMID: 33142884 PMCID: PMC7662651 DOI: 10.3390/ijms21218164] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 10/28/2020] [Accepted: 10/29/2020] [Indexed: 12/13/2022] Open
Abstract
Redox reactions are of high fundamental and practical interest since they are involved in both normal physiology and the pathogenesis of various diseases. However, this area of research has always been a relatively problematic field in the context of analytical approaches, mostly because of the unstable nature of the compounds that are measured. Genetically encoded sensors allow for the registration of highly reactive molecules in real-time mode and, therefore, they began a new era in redox biology. Their strongest points manifest most brightly in in vivo experiments and pave the way for the non-invasive investigation of biochemical pathways that proceed in organisms from different systematic groups. In the first part of the review, we briefly describe the redox sensors that were used in vivo as well as summarize the model systems to which they were applied. Next, we thoroughly discuss the biological results obtained in these studies in regard to animals, plants, as well as unicellular eukaryotes and prokaryotes. We hope that this work reflects the amazing power of this technology and can serve as a useful guide for biologists and chemists who work in the field of redox processes.
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Affiliation(s)
- Alexander I. Kostyuk
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.S.P.); (A.D.K.); (D.A.K.); (D.I.M.); (O.V.P.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Anastasiya S. Panova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.S.P.); (A.D.K.); (D.A.K.); (D.I.M.); (O.V.P.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Aleksandra D. Kokova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.S.P.); (A.D.K.); (D.A.K.); (D.I.M.); (O.V.P.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Daria A. Kotova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.S.P.); (A.D.K.); (D.A.K.); (D.I.M.); (O.V.P.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Dmitry I. Maltsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.S.P.); (A.D.K.); (D.A.K.); (D.I.M.); (O.V.P.); (V.V.B.)
- Federal Center for Cerebrovascular Pathology and Stroke, 117997 Moscow, Russia
| | - Oleg V. Podgorny
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.S.P.); (A.D.K.); (D.A.K.); (D.I.M.); (O.V.P.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Vsevolod V. Belousov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.S.P.); (A.D.K.); (D.A.K.); (D.I.M.); (O.V.P.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
- Federal Center for Cerebrovascular Pathology and Stroke, 117997 Moscow, Russia
- Institute for Cardiovascular Physiology, Georg August University Göttingen, D-37073 Göttingen, Germany
| | - Dmitry S. Bilan
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.S.P.); (A.D.K.); (D.A.K.); (D.I.M.); (O.V.P.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
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62
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Aberrant Intracellular pH Regulation Limiting Glyceraldehyde-3-Phosphate Dehydrogenase Activity in the Glucose-Sensitive Yeast tps1Δ Mutant. mBio 2020; 11:mBio.02199-20. [PMID: 33109759 PMCID: PMC7593968 DOI: 10.1128/mbio.02199-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glucose catabolism is the backbone of metabolism in most organisms. In spite of numerous studies and extensive knowledge, major controls on glycolysis and its connections to the other metabolic pathways remain to be discovered. A striking example is provided by the extreme glucose sensitivity of the yeast tps1Δ mutant, which undergoes apoptosis in the presence of just a few millimolar glucose. Previous work has shown that the conspicuous glucose-induced hyperaccumulation of the glycolytic metabolite fructose-1,6-bisphosphate (Fru1,6bisP) in tps1Δ cells triggers apoptosis through activation of the Ras-cAMP-protein kinase A (PKA) signaling pathway. However, the molecular cause of this Fru1,6bisP hyperaccumulation has remained unclear. We now provide evidence that the persistent drop in intracellular pH upon glucose addition to tps1Δ cells likely compromises the activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a major glycolytic enzyme downstream of Fru1,6bisP, due to its unusually high pH optimum. Our work highlights the potential importance of intracellular pH fluctuations for control of major metabolic pathways. Whereas the yeast Saccharomyces cerevisiae shows great preference for glucose as a carbon source, a deletion mutant in trehalose-6-phosphate synthase, tps1Δ, is highly sensitive to even a few millimolar glucose, which triggers apoptosis and cell death. Glucose addition to tps1Δ cells causes deregulation of glycolysis with hyperaccumulation of metabolites upstream and depletion downstream of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The apparent metabolic barrier at the level of GAPDH has been difficult to explain. We show that GAPDH isozyme deletion, especially Tdh3, further aggravates glucose sensitivity and metabolic deregulation of tps1Δ cells, but overexpression does not rescue glucose sensitivity. GAPDH has an unusually high pH optimum of 8.0 to 8.5, which is not altered by tps1Δ. Whereas glucose causes short, transient intracellular acidification in wild-type cells, in tps1Δ cells, it causes permanent intracellular acidification. The hxk2Δ and snf1Δ suppressors of tps1Δ restore the transient acidification. These results suggest that GAPDH activity in the tps1Δ mutant may be compromised by the persistently low intracellular pH. Addition of NH4Cl together with glucose at high extracellular pH to tps1Δ cells abolishes the pH drop and reduces glucose-6-phosphate (Glu6P) and fructose-1,6-bisphosphate (Fru1,6bisP) hyperaccumulation. It also reduces the glucose uptake rate, but a similar reduction in glucose uptake rate in a tps1Δ hxt2,4,5,6,7Δ strain does not prevent glucose sensitivity and Fru1,6bisP hyperaccumulation. Hence, our results suggest that the glucose-induced intracellular acidification in tps1Δ cells may explain, at least in part, the apparent glycolytic bottleneck at GAPDH but does not appear to fully explain the extreme glucose sensitivity of the tps1Δ mutant.
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63
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Yang Q, Zhang X, Song Y, Li K, Shi H, Xiao H, Ma Y. Label-Free in Situ pH Monitoring in a Single Living Cell Using an Optical Nanoprobe. ACTA ACUST UNITED AC 2020; 3. [PMID: 33073180 DOI: 10.1002/mds3.10079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Intracellular pH plays critical roles in cell and tissue functions during processes such as metabolism, proliferation, apoptosis, ion transportation, endocytosis, muscle contraction and so on. It is thus an important biomarker that can readily be used to monitor the physiological status of a cell. Thus, disrupted intracellular pH may serve as an early indicator of cell dysfunction and deterioration. Various methods have been developed to detect cellular pH, such as pH-sensitive labeling reagents with fluorescent or Raman signals. However, excessive cellular uptake of these reagents will not only disrupt cell viability but also compromise effective long-term monitoring. Here, we present a novel fiber-optic fluorescent nanoprobe with a high spatial resolution for label-free, subcellular pH sensing. The probe has a fast response time (~20 seconds) with minimum invasiveness and excellent pH resolution (0.02 pH units) within a biologically relevant pH environment ranging from 6.17 to 8.11. Its applicability was demonstrated on cultured A549 lung cancer cells, and its efficacy was further testified in two typical cytotoxic cases using carbonylcyanide 3-chlorophenyl hydrazine, titanium dioxide, and nanoparticles. The probe can readily detect the pH variations among cells under toxin/nanoparticles administration, enabling direct monitoring of the early onset of physiological or pathological events with high spatiotemporal resolution. This platform has excellent promise as a minimum invasive diagnostic tool for pH-related cellular mechanism studies, such as inflammation, cytotoxicity, drug resistance, carcinogenesis, stem cell differentiation and so on.
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Affiliation(s)
- Qingbo Yang
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, United States.,Center for Biomedical Research, Missouri University of Science and Technology, Rolla, MO 65409, United States
| | - Xiaobei Zhang
- Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, United States
| | - Yang Song
- Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, United States
| | - Ke Li
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, United States
| | - Honglan Shi
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, United States.,Center for Biomedical Research, Missouri University of Science and Technology, Rolla, MO 65409, United States
| | - Hai Xiao
- Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, United States
| | - Yinfa Ma
- Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, United States.,Center for Biomedical Research, Missouri University of Science and Technology, Rolla, MO 65409, United States
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64
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Mouton SN, Thaller DJ, Crane MM, Rempel IL, Terpstra OT, Steen A, Kaeberlein M, Lusk CP, Boersma AJ, Veenhoff LM. A physicochemical perspective of aging from single-cell analysis of pH, macromolecular and organellar crowding in yeast. eLife 2020; 9:e54707. [PMID: 32990592 PMCID: PMC7556870 DOI: 10.7554/elife.54707] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 09/28/2020] [Indexed: 01/03/2023] Open
Abstract
Cellular aging is a multifactorial process that is characterized by a decline in homeostatic capacity, best described at the molecular level. Physicochemical properties such as pH and macromolecular crowding are essential to all molecular processes in cells and require maintenance. Whether a drift in physicochemical properties contributes to the overall decline of homeostasis in aging is not known. Here, we show that the cytosol of yeast cells acidifies modestly in early aging and sharply after senescence. Using a macromolecular crowding sensor optimized for long-term FRET measurements, we show that crowding is rather stable and that the stability of crowding is a stronger predictor for lifespan than the absolute crowding levels. Additionally, in aged cells, we observe drastic changes in organellar volume, leading to crowding on the micrometer scale, which we term organellar crowding. Our measurements provide an initial framework of physicochemical parameters of replicatively aged yeast cells.
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Affiliation(s)
- Sara N Mouton
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenGroningenNetherlands
| | - David J Thaller
- Department of Cell Biology, Yale School of MedicineNew HavenUnited States
| | - Matthew M Crane
- Department of Pathology, School of Medicine, University of WashingtonSeattleUnited States
| | - Irina L Rempel
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenGroningenNetherlands
| | - Owen T Terpstra
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenGroningenNetherlands
| | - Anton Steen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenGroningenNetherlands
| | - Matt Kaeberlein
- Department of Pathology, School of Medicine, University of WashingtonSeattleUnited States
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of MedicineNew HavenUnited States
| | | | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenGroningenNetherlands
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65
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Bagamery LE, Justman QA, Garner EC, Murray AW. A Putative Bet-Hedging Strategy Buffers Budding Yeast against Environmental Instability. Curr Biol 2020; 30:4563-4578.e4. [PMID: 32976801 DOI: 10.1016/j.cub.2020.08.092] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 07/20/2020] [Accepted: 08/26/2020] [Indexed: 12/19/2022]
Abstract
To grow and divide, cells must extract resources from dynamic and unpredictable environments. Many organisms use different metabolic strategies for distinct contexts. Budding yeast can produce ATP from carbon sources by mechanisms that prioritize either speed (fermentation) or yield (respiration). Withdrawing glucose from exponentially growing cells reveals variability in their ability to switch from fermentation to respiration. We observe two subpopulations of glucose-starved cells: recoverers, which rapidly adapt and resume growth, and arresters, which enter a shock state characterized by deformation of many cellular structures, including mitochondria. These states are heritable, and on high glucose, arresters grow and divide faster than recoverers. Recoverers have a fitness advantage during a carbon source shift but are less fit in a constant, high-glucose environment, and we observe natural variation in the frequency of the two states across wild yeast strains. These experiments suggest that bet hedging has evolved in budding yeast.
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Affiliation(s)
- Laura E Bagamery
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Quincey A Justman
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA.
| | - Andrew W Murray
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA.
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66
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Soleja N, Irfan, Mohsin M. Ratiometric imaging of flux dynamics of cobalt with an optical sensor. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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67
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Babazadeh R, Ahmadpour D, Jia S, Hao X, Widlund P, Schneider K, Eisele F, Edo LD, Smits GJ, Liu B, Nystrom T. Syntaxin 5 Is Required for the Formation and Clearance of Protein Inclusions during Proteostatic Stress. Cell Rep 2020; 28:2096-2110.e8. [PMID: 31433985 DOI: 10.1016/j.celrep.2019.07.053] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 06/14/2019] [Accepted: 07/17/2019] [Indexed: 12/12/2022] Open
Abstract
Spatial sorting to discrete quality control sites in the cell is a process harnessing the toxicity of aberrant proteins. We show that the yeast t-snare phosphoprotein syntaxin5 (Sed5) acts as a key factor in mitigating proteotoxicity and the spatial deposition and clearance of IPOD (insoluble protein deposit) inclusions associates with the disaggregase Hsp104. Sed5 phosphorylation promotes dynamic movement of COPII-associated Hsp104 and boosts disaggregation by favoring anterograde ER-to-Golgi trafficking. Hsp104-associated aggregates co-localize with Sed5 as well as components of the ER, trans Golgi network, and endocytic vesicles, transiently during proteostatic stress, explaining mechanistically how misfolded and aggregated proteins formed at the vicinity of the ER can hitchhike toward vacuolar IPOD sites. Many inclusions become associated with mitochondria in a HOPS/vCLAMP-dependent manner and co-localize with Vps39 (HOPS/vCLAMP) and Vps13, which are proteins providing contacts between vacuole and mitochondria. Both Vps39 and Vps13 are required also for efficient Sed5-dependent clearance of aggregates.
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Affiliation(s)
- Roja Babazadeh
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Doryaneh Ahmadpour
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Song Jia
- School of Life Science, Northeast Agricultural University, No. 600 Changjiang Street, Xiangfang District, Harbin 150030, China
| | - Xinxin Hao
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Per Widlund
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Kara Schneider
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Frederik Eisele
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Laura Dolz Edo
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam 1090, the Netherlands
| | - Gertien J Smits
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam 1090, the Netherlands
| | - Beidong Liu
- Department of Chemistry & Molecular Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Thomas Nystrom
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Gothenburg 405 30, Sweden.
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68
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Nitrogen coordinated import and export of arginine across the yeast vacuolar membrane. PLoS Genet 2020; 16:e1008966. [PMID: 32776922 PMCID: PMC7440668 DOI: 10.1371/journal.pgen.1008966] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 08/20/2020] [Accepted: 06/30/2020] [Indexed: 11/19/2022] Open
Abstract
The vacuole of the yeast Saccharomyces cerevisiae plays an important role in nutrient storage. Arginine, in particular, accumulates in the vacuole of nitrogen-replete cells and is mobilized to the cytosol under nitrogen starvation. The arginine import and export systems involved remain poorly characterized, however. Furthermore, how their activity is coordinated by nitrogen remains unknown. Here we characterize Vsb1 as a novel vacuolar membrane protein of the APC (amino acid-polyamine-organocation) transporter superfamily which, in nitrogen-replete cells, is essential to active uptake and storage of arginine into the vacuole. A shift to nitrogen starvation causes apparent inhibition of Vsb1-dependent activity and mobilization of stored vacuolar arginine to the cytosol. We further show that this arginine export involves Ypq2, a vacuolar protein homologous to the human lysosomal cationic amino acid exporter PQLC2 and whose activity is detected only in nitrogen-starved cells. Our study unravels the main arginine import and export systems of the yeast vacuole and suggests that they are inversely regulated by nitrogen. The lysosome-like vacuole of the yeast Saccharomyces cerevisiae is an important storage compartment for diverse nutrients, including the cationic amino acid arginine, which accumulates at high concentrations in this organelle in nitrogen-replete cells. When these cells are transferred to a nitrogen-free medium, vacuolar arginine is mobilized to the cytosol, where it is used as an alternative nitrogen source to sustain growth. Although this phenomenon has been observed since the 1980s, the identity of the vacuolar transporters involved in the accumulation and the mobilization of arginine is not well established, and whether these processes are regulated according to nutritional cues remains unknown. In this study, we exploited in vitro and in vivo uptake assays in vacuoles to identify and characterize Vsb1 and Ypq2 as vacuolar membrane proteins mediating import and export of arginine, respectively. We further provide evidence that Vsb1 and Ypq2 are inversely regulated according to the nitrogen status of the cell. Our study sheds new light on the poorly studied topic of the diversity and metabolic control of vacuolar transporters. It also raises novel questions about the molecular mechanisms underlying their coordinated regulation and, by extension, the regulation of lysosomal transporters in human cells.
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69
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Nüske E, Marini G, Richter D, Leng W, Bogdanova A, Franzmann TM, Pigino G, Alberti S. Filament formation by the translation factor eIF2B regulates protein synthesis in starved cells. Biol Open 2020; 9:bio046391. [PMID: 32554487 PMCID: PMC7358136 DOI: 10.1242/bio.046391] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/26/2020] [Indexed: 12/11/2022] Open
Abstract
Cells exposed to starvation have to adjust their metabolism to conserve energy and protect themselves. Protein synthesis is one of the major energy-consuming processes and as such has to be tightly controlled. Many mechanistic details about how starved cells regulate the process of protein synthesis are still unknown. Here, we report that the essential translation initiation factor eIF2B forms filaments in starved budding yeast cells. We demonstrate that filamentation is triggered by starvation-induced acidification of the cytosol, which is caused by an influx of protons from the extracellular environment. We show that filament assembly by eIF2B is necessary for rapid and efficient downregulation of translation. Importantly, this mechanism does not require the kinase Gcn2. Furthermore, analysis of site-specific variants suggests that eIF2B assembly results in enzymatically inactive filaments that promote stress survival and fast recovery of cells from starvation. We propose that translation regulation through filament assembly is an efficient mechanism that allows yeast cells to adapt to fluctuating environments.
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Affiliation(s)
- Elisabeth Nüske
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Guendalina Marini
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Doris Richter
- Department of Cellular Biochemistry Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Weihua Leng
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Aliona Bogdanova
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Titus M Franzmann
- Department of Cellular Biochemistry Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Simon Alberti
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
- Department of Cellular Biochemistry Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
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70
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Kloehn J, Harding CR, Soldati-Favre D. Supply and demand-heme synthesis, salvage and utilization by Apicomplexa. FEBS J 2020; 288:382-404. [PMID: 32530125 DOI: 10.1111/febs.15445] [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: 04/18/2020] [Revised: 05/23/2020] [Accepted: 06/05/2020] [Indexed: 01/05/2023]
Abstract
The Apicomplexa phylum groups important human and animal pathogens that cause severe diseases, encompassing malaria, toxoplasmosis, and cryptosporidiosis. In common with most organisms, apicomplexans rely on heme as cofactor for several enzymes, including cytochromes of the electron transport chain. This heme derives from de novo synthesis and/or the development of uptake mechanisms to scavenge heme from their host. Recent studies have revealed that heme synthesis is essential for Toxoplasma gondii tachyzoites, as well as for the mosquito and liver stages of Plasmodium spp. In contrast, the erythrocytic stages of the malaria parasites rely on scavenging heme from the host red blood cell. The unusual heme synthesis pathway in Apicomplexa spans three cellular compartments and comprises enzymes of distinct ancestral origin, providing promising drug targets. Remarkably given the requirement for heme, T. gondii can tolerate the loss of several heme synthesis enzymes at a high fitness cost, while the ferrochelatase is essential for survival. These findings indicate that T. gondii is capable of salvaging heme precursors from its host. Furthermore, heme is implicated in the activation of the key antimalarial drug artemisinin. Recent findings established that a reduction in heme availability corresponds to decreased sensitivity to artemisinin in T. gondii and Plasmodium falciparum, providing insights into the possible development of combination therapies to tackle apicomplexan parasites. This review describes the microeconomics of heme in Apicomplexa, from supply, either from de novo synthesis or scavenging, to demand by metabolic pathways, including the electron transport chain.
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Affiliation(s)
- Joachim Kloehn
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Switzerland
| | - Clare R Harding
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity & Inflammation, University of Glasgow, UK
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71
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Triandafillou CG, Drummond DA. Live Cell Measurement of the Intracellular pH of Yeast by Flow Cytometry Using a Genetically-Encoded Fluorescent Reporter. Bio Protoc 2020; 10:e3653. [PMID: 33659323 DOI: 10.21769/bioprotoc.3653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/23/2020] [Accepted: 03/18/2020] [Indexed: 11/02/2022] Open
Abstract
The intracellular pH of yeast is a tightly regulated physiological cue that changes in response to growth state and environmental conditions. Fluorescent reporters, which have altered fluorescence in response to local pH changes, can be used to measure intracellular pH. While microscopy is often used to make such measurements, it is relatively low-throughput such that collecting enough data to fully characterize populations of cells is challenging. Flow cytometry avoids this drawback, and is a powerful tool that allows for rapid, high-throughput measurement of fluorescent readouts in individual cells. When combined with pH-sensitive fluorescent reporters, it can be used to characterize the intracellular pH of large populations of cells at the single-cell level. We adapted microscopy and flow-cytometry based methods to measure the intracellular pH of yeast. Cells can be grown under near-native conditions up until the point of measurement, and the protocol can be adapted to single-point or dynamic (time-resolved) measurements during changing environmental conditions.
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Affiliation(s)
| | - D Allan Drummond
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, USA.,Department of Human Genetics, University of Chicago, Chicago, USA
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72
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Lucena RM, Dolz-Edo L, Brul S, de Morais MA, Smits G. Extreme Low Cytosolic pH Is a Signal for Cell Survival in Acid Stressed Yeast. Genes (Basel) 2020; 11:genes11060656. [PMID: 32560106 PMCID: PMC7349538 DOI: 10.3390/genes11060656] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 12/18/2022] Open
Abstract
Yeast biomass is recycled in the process of bioethanol production using treatment with dilute sulphuric acid to control the bacterial population. This treatment can lead to loss of cell viability, with consequences on the fermentation yield. Thus, the aim of this study was to define the functional cellular responses to inorganic acid stress. Saccharomyces cerevisiae strains with mutation in several signalling pathways, as well as cells expressing pH-sensitive GFP derivative ratiometric pHluorin, were tested for cell survival and cytosolic pH (pHc) variation during exposure to low external pH (pHex). Mutants in calcium signalling and proton extrusion were transiently sensitive to low pHex, while the CWI slt2Δ mutant lost viability. Rescue of this mutant was observed when cells were exposed to extreme low pHex or glucose starvation and was dependent on the induced reduction of pHc. Therefore, a lowered pHc leads to a complete growth arrest, which protects the cells from lethal stress and keeps cells alive. Cytosolic pH is thus a signal that directs the growth stress-tolerance trade-off in yeast. A regulatory model was proposed to explain this mechanism, indicating the impairment of glucan synthesis as the primary cause of low pHex sensitivity.
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Affiliation(s)
- Rodrigo Mendonça Lucena
- Department of Genetics, Biosciences Centre, Federal University of Pernambuco, Recife 50670-901, Brazil;
- Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, Netherlands; (L.D.-E.); (S.B.)
| | - Laura Dolz-Edo
- Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, Netherlands; (L.D.-E.); (S.B.)
| | - Stanley Brul
- Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, Netherlands; (L.D.-E.); (S.B.)
| | - Marcos Antonio de Morais
- Department of Genetics, Biosciences Centre, Federal University of Pernambuco, Recife 50670-901, Brazil;
- Correspondence: (G.S.); (M.A.d.M.J.)
| | - Gertien Smits
- Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, Netherlands; (L.D.-E.); (S.B.)
- Correspondence: (G.S.); (M.A.d.M.J.)
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73
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The Preservative Sorbic Acid Targets Respiration, Explaining the Resistance of Fermentative Spoilage Yeast Species. mSphere 2020; 5:5/3/e00273-20. [PMID: 32461271 PMCID: PMC7253596 DOI: 10.1128/msphere.00273-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A small number (10 to 20) of yeast species cause major spoilage in foods. Spoilage yeasts of soft drinks are resistant to preservatives like sorbic acid, and they are highly fermentative, generating large amounts of carbon dioxide gas. Conversely, many yeast species derive energy from respiration only, and most of these are sorbic acid sensitive and so prevented from causing spoilage. This led us to hypothesize that sorbic acid may specifically inhibit respiration. Tests with respirofermentative yeasts showed that sorbic acid was more inhibitory to both Saccharomyces cerevisiae and Zygosaccharomyces bailii during respiration (of glycerol) than during fermentation (of glucose). The respiration-only species Rhodotorula glutinis was equally sensitive when growing on either carbon source, suggesting that ability to ferment glucose specifically enables sorbic acid-resistant growth. Sorbic acid inhibited the respiration process more strongly than fermentation. We present a data set supporting a correlation between the level of fermentation and sorbic acid resistance across 191 yeast species. Other weak acids, C2 to C8, inhibited respiration in accordance with their partition coefficients, suggesting that effects on mitochondrial respiration were related to membrane localization rather than cytosolic acidification. Supporting this, we present evidence that sorbic acid causes production of reactive oxygen species, the formation of petite (mitochondrion-defective) cells, and Fe-S cluster defects. This work rationalizes why yeasts that can grow in sorbic acid-preserved foods tend to be fermentative in nature. This may inform more-targeted approaches for tackling these spoilage organisms, particularly as the industry migrates to lower-sugar drinks, which could favor respiration over fermentation in many spoilage yeasts.IMPORTANCE Spoilage by yeasts and molds is a major contributor to food and drink waste, which undermines food security. Weak acid preservatives like sorbic acid help to stop spoilage, but some yeasts, commonly associated with spoilage, are resistant to sorbic acid. Different yeasts generate energy for growth by the processes of respiration and/or fermentation. Here, we show that sorbic acid targets the process of respiration, so fermenting yeasts are more resistant. Fermentative yeasts are also those usually found in spoilage incidents. This insight helps to explain the spoilage of sorbic acid-preserved foods by yeasts and can inform new strategies for effective control. This is timely as the sugar content of products like soft drinks is being lowered, which may favor respiration over fermentation in key spoilage yeasts.
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74
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Botman D, van Heerden JH, Teusink B. An Improved ATP FRET Sensor For Yeast Shows Heterogeneity During Nutrient Transitions. ACS Sens 2020; 5:814-822. [PMID: 32077276 PMCID: PMC7106129 DOI: 10.1021/acssensors.9b02475] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 02/20/2020] [Indexed: 01/07/2023]
Abstract
Adenosine 5-triphosphate (ATP) is the main free energy carrier in metabolism. In budding yeast, shifts to glucose-rich conditions cause dynamic changes in ATP levels, but it is unclear how heterogeneous these dynamics are at a single-cell level. Furthermore, pH also changes and affects readout of fluorescence-based biosensors for single-cell measurements. To measure ATP changes reliably in single yeast cells, we developed yAT1.03, an adapted version of the AT1.03 ATP biosensor, that is pH-insensitive. We show that pregrowth conditions largely affect ATP dynamics during transitions. Moreover, single-cell analyses showed a large variety in ATP responses, which implies large differences of glycolytic startup between individual cells. We found three clusters of dynamic responses, and we show that a small subpopulation of wild-type cells reached an imbalanced state during glycolytic startup, characterized by low ATP levels. These results confirm the need for new tools to study dynamic responses of individual cells in dynamic environments.
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Affiliation(s)
- Dennis Botman
- Systems Biology Lab/AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Johan H. van Heerden
- Systems Biology Lab/AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Bas Teusink
- Systems Biology Lab/AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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75
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Brito AS, Neuhäuser B, Wintjens R, Marini AM, Boeckstaens M. Yeast filamentation signaling is connected to a specific substrate translocation mechanism of the Mep2 transceptor. PLoS Genet 2020; 16:e1008634. [PMID: 32069286 PMCID: PMC7048316 DOI: 10.1371/journal.pgen.1008634] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 02/28/2020] [Accepted: 01/28/2020] [Indexed: 11/18/2022] Open
Abstract
The dimorphic transition from the yeast to the filamentous form of growth allows cells to explore their environment for more suitable niches and is often crucial for the virulence of pathogenic fungi. In contrast to their Mep1/3 paralogues, fungal Mep2-type ammonium transport proteins of the conserved Mep-Amt-Rh family have been assigned an additional receptor role required to trigger the filamentation signal in response to ammonium scarcity. Here, genetic, kinetic and structure-function analyses were used to shed light on the poorly characterized signaling role of Saccharomyces cerevisiae Mep2. We show that Mep2 variants lacking the C-terminal tail conserve the ability to induce filamentation, revealing that signaling can proceed in the absence of exclusive binding of a putative partner to the largest cytosolic domain of the protein. Our data support that filamentation signaling requires the conformational changes accompanying substrate translocation through the pore crossing the hydrophobic core of Mep2. pHluorin reporter assays show that the transport activity of Mep2 and of non-signaling Mep1 differently affect yeast cytosolic pH in vivo, and that the unique pore variant Mep2H194E, with apparent uncoupling of transport and signaling functions, acquires increased ability of acidification. Functional characterization in Xenopus oocytes reveals that Mep2 mediates electroneutral substrate translocation while Mep1 performs electrogenic transport. Our findings highlight that the Mep2-dependent filamentation induction is connected to its specific transport mechanism, suggesting a role of pH in signal mediation. Finally, we show that the signaling process is conserved for the Mep2 protein from the human pathogen Candida albicans. Fungal Mep2-type ammonium transport proteins of the conserved Mep-Amt-Rh family that includes human Rhesus factors are specifically required to allow filamentation in response to ammonium limitation. These proteins were therefore assigned a receptor role while the underlying mechanism of signal transduction remains poorly understood. The “transceptor” property has subsequently been proposed to concern transporters of all kind of micro- and macro- nutrients in eukaryotes, from fungi to human. However, bringing the firm demonstration of their existence remains challenging as variants with full uncoupling of transport and receptor functions are difficult to obtain. Our data question the involvement of the C-terminal extremity of Saccharomyces cerevisiae Mep2 in the signal mediation leading to filamentation. If signaling partners exist, they should also bind to cytosolic loops and/or membrane-embedded domains. The capacity of Mep2 to enable filamentation is closely intertwined to the mechanism of substrate translocation through the pore of the hydrophobic core of the protein. In Xenopus oocytes, the transport activity of non-signaling Mep1 is electrogenic while it is electroneutral for Mep2, the latter likely translocating the weak base NH3, but not the proton released after NH4+ recognition and depronotation. We propose that given consequences of a Mep2-specific transport process, such as an intracellular pH modification, could be the underlying cause of the filamentation signal ensured by Mep2-type proteins.
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Affiliation(s)
- Ana Sofia Brito
- Biology of Membrane Transport Laboratory, Molecular Biology Department, Université Libre de Bruxelles, Gosselies, Belgium
| | - Benjamin Neuhäuser
- Institute of Crop Science, Nutritional Crop Physiology, University of Hohenheim, Stuttgart, Germany
| | - René Wintjens
- Unité Microbiologie, Chimie Bioorganique et Macromoléculaire, Département RD3, Faculté de Pharmacie, Université Libre de Bruxelles, Brussels, Belgium
| | - Anna Maria Marini
- Biology of Membrane Transport Laboratory, Molecular Biology Department, Université Libre de Bruxelles, Gosselies, Belgium
- * E-mail: (AMM); (MB)
| | - Mélanie Boeckstaens
- Biology of Membrane Transport Laboratory, Molecular Biology Department, Université Libre de Bruxelles, Gosselies, Belgium
- * E-mail: (AMM); (MB)
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Tsouka S, Hatzimanikatis V. redLips: a comprehensive mechanistic model of the lipid metabolic network of yeast. FEMS Yeast Res 2020; 20:5739921. [DOI: 10.1093/femsyr/foaa006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/17/2020] [Indexed: 12/12/2022] Open
Abstract
ABSTRACTOver the last decades, yeast has become a key model organism for the study of lipid biochemistry. Because the regulation of lipids has been closely linked to various physiopathologies, the study of these biomolecules could lead to new diagnostics and treatments. Before the field can reach this point, however, sufficient tools for integrating and analyzing the ever-growing availability of lipidomics data will need to be developed. To this end, genome-scale models (GEMs) of metabolic networks are useful tools, though their large size and complexity introduces too much uncertainty in the accuracy of predicted outcomes. Ideally, therefore, a model for studying lipids would contain only the pathways required for the proper analysis of these biomolecules, but would not be an ad hoc reduction. We hereby present a metabolic model that focuses on lipid metabolism constructed through the integration of detailed lipid pathways into an already existing GEM of Saccharomyces cerevisiae. Our model was then systematically reduced around the subsystems defined by these pathways to provide a more manageable model size for complex studies. We show that this model is as consistent and inclusive as other yeast GEMs regarding the focus and detail on the lipid metabolism, and can be used as a scaffold for integrating lipidomics data to improve predictions in studies of lipid-related biological functions.
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Affiliation(s)
- S Tsouka
- Laboratory of Computational Systems Biotechnology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - V Hatzimanikatis
- Laboratory of Computational Systems Biotechnology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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77
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Hakkaart X, Liu Y, Hulst M, El Masoudi A, Peuscher E, Pronk J, van Gulik W, Daran-Lapujade P. Physiological responses of Saccharomyces cerevisiae to industrially relevant conditions: Slow growth, low pH, and high CO 2 levels. Biotechnol Bioeng 2020; 117:721-735. [PMID: 31654410 PMCID: PMC7028085 DOI: 10.1002/bit.27210] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 10/12/2019] [Accepted: 10/22/2019] [Indexed: 12/21/2022]
Abstract
Engineered strains of Saccharomyces cerevisiae are used for industrial production of succinic acid. Optimal process conditions for dicarboxylic‐acid yield and recovery include slow growth, low pH, and high CO2. To quantify and understand how these process parameters affect yeast physiology, this study investigates individual and combined impacts of low pH (3.0) and high CO2 (50%) on slow‐growing chemostat and retentostat cultures of the reference strain S. cerevisiae CEN.PK113‐7D. Combined exposure to low pH and high CO2 led to increased maintenance‐energy requirements and death rates in aerobic, glucose‐limited cultures. Further experiments showed that these effects were predominantly caused by low pH. Growth under ammonium‐limited, energy‐excess conditions did not aggravate or ameliorate these adverse impacts. Despite the absence of a synergistic effect of low pH and high CO2 on physiology, high CO2 strongly affected genome‐wide transcriptional responses to low pH. Interference of high CO2 with low‐pH signaling is consistent with low‐pH and high‐CO2 signals being relayed via common (MAPK) signaling pathways, notably the cell wall integrity, high‐osmolarity glycerol, and calcineurin pathways. This study highlights the need to further increase robustness of cell factories to low pH for carboxylic‐acid production, even in organisms that are already applied at industrial scale.
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Affiliation(s)
- Xavier Hakkaart
- Department of Biotechnology, Delft University of Technology, van der Maasweg, Delft, The Netherlands
| | - Yaya Liu
- Department of Biotechnology, Delft University of Technology, van der Maasweg, Delft, The Netherlands
| | - Mandy Hulst
- Department of Biotechnology, Delft University of Technology, van der Maasweg, Delft, The Netherlands
| | - Anissa El Masoudi
- Department of Biotechnology, Delft University of Technology, van der Maasweg, Delft, The Netherlands
| | - Eveline Peuscher
- Department of Biotechnology, Delft University of Technology, van der Maasweg, Delft, The Netherlands
| | - Jack Pronk
- Department of Biotechnology, Delft University of Technology, van der Maasweg, Delft, The Netherlands
| | - Walter van Gulik
- Department of Biotechnology, Delft University of Technology, van der Maasweg, Delft, The Netherlands
| | - Pascale Daran-Lapujade
- Department of Biotechnology, Delft University of Technology, van der Maasweg, Delft, The Netherlands
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78
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Kinetic coupling of the respiratory chain with ATP synthase, but not proton gradients, drives ATP production in cristae membranes. Proc Natl Acad Sci U S A 2020; 117:2412-2421. [PMID: 31964824 DOI: 10.1073/pnas.1917968117] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Mitochondria have a characteristic ultrastructure with invaginations of the inner membrane called cristae that contain the protein complexes of the oxidative phosphorylation system. How this particular morphology of the respiratory membrane impacts energy conversion is currently unknown. One proposed role of cristae formation is to facilitate the establishment of local proton gradients to fuel ATP synthesis. Here, we determined the local pH values at defined sublocations within mitochondria of respiring yeast cells by fusing a pH-sensitive GFP to proteins residing in different mitochondrial subcompartments. Only a small proton gradient was detected over the inner membrane in wild type or cristae-lacking cells. Conversely, the obtained pH values did barely permit ATP synthesis in a reconstituted system containing purified yeast F1F0 ATP synthase, although, thermodynamically, a sufficiently high driving force was applied. At higher driving forces, where robust ATP synthesis was observed, a P-side pH value of 6 increased the ATP synthesis rate 3-fold compared to pH 7. In contrast, when ATP synthase was coreconstituted with an active proton-translocating cytochrome oxidase, ATP synthesis readily occurred at the measured, physiological pH values. Our study thus reveals that the morphology of the inner membrane does not influence the subcompartmental pH values and is not necessary for robust oxidative phosphorylation in mitochondria. Instead, it is likely that the dense packing of the oxidative phosphorylation complexes in the cristae membranes assists kinetic coupling between proton pumping and ATP synthesis.
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79
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Gabba M, Poolman B. Physiochemical Modeling of Vesicle Dynamics upon Osmotic Upshift. Biophys J 2020; 118:435-447. [PMID: 31948692 PMCID: PMC6976812 DOI: 10.1016/j.bpj.2019.11.3383] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 11/22/2019] [Indexed: 02/06/2023] Open
Abstract
We modeled the relaxation dynamics of (lipid) vesicles upon osmotic upshift, taking into account volume variation, chemical reaction kinetics, and passive transport across the membrane. We focused on the relaxation kinetics upon addition of impermeable osmolytes such as KCl and membrane-permeable solutes such as weak acids. We studied the effect of the most relevant physical parameters on the dynamic behavior of the system, as well as on the relaxation rates. We observe that 1) the dynamic complexity of the relaxation kinetics depends on the number of permeable species; 2) the permeability coefficients (P) and the weak acid strength (pKa-values) determine the dynamic behavior of the system; 3) the vesicle size does not affect the dynamics, but only the relaxation rates of the system; and 4) heterogeneities in the vesicle size provoke stretching of the relaxation curves. The model was successfully benchmarked for determining permeability coefficients by fitting of our experimental relaxation curves and by comparison of the data with literature values (in this issue of Biophysical Journal). To describe the dynamics of yeast cells upon osmotic upshift, we extended the model to account for turgor pressure and nonosmotic volume.
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Affiliation(s)
- Matteo Gabba
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands.
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80
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Zhou H, Nguyen L, Arnesano C, Ando Y, Raval M, Rodgers JT, Fraser S, Lu R, Shen K. Non-invasive Optical Biomarkers Distinguish and Track the Metabolic Status of Single Hematopoietic Stem Cells. iScience 2020; 23:100831. [PMID: 31982780 PMCID: PMC6994633 DOI: 10.1016/j.isci.2020.100831] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 12/11/2019] [Accepted: 01/07/2020] [Indexed: 12/28/2022] Open
Abstract
Metabolism is a key regulator of hematopoietic stem cell (HSC) functions. There is a lack of real-time, non-invasive approaches to evaluate metabolism in single HSCs. Using fluorescence lifetime imaging microscopy, we developed a set of metabolic optical biomarkers (MOBs) from the auto-fluorescent properties of metabolic coenzymes NAD(P)H and FAD. The MOBs revealed the enhanced glycolysis, low oxidative metabolism, and distinct mitochondrial localization of HSCs. Importantly, the fluorescence lifetime of enzyme-bound NAD(P)H (τbound) can non-invasively monitor the glycolytic/lactate dehydrogenase activity in single HSCs. As a proof of concept for metabolism-based cell sorting, we further identified HSCs within the Lineage-cKit+Sca1+ (KLS) hematopoietic stem/progenitor population using MOBs and a machine-learning algorithm. Moreover, we revealed the dynamic changes of MOBs, and the association of longer τbound with enhanced glycolysis under HSC stemness-maintaining conditions during HSC culture. Our work thus provides a new paradigm to identify and track the metabolism of single HSCs non-invasively and in real time. Metabolic optical biomarkers non-invasively distinguish HSCs from early progenitors NAD(P)H τbound reflects lactate dehydrogenase activity in single fresh/cultured HSCs pHi correlates with τbound in hematopoietic populations, with HSCs being the highest Optical biomarkers track metabolic changes and response to drugs in cultured HSCs
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Affiliation(s)
- Hao Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Lisa Nguyen
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Cosimo Arnesano
- Translational Imaging Center, University of Southern California, Los Angeles, CA 90089, USA; Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Yuta Ando
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Manmeet Raval
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Joseph T Rodgers
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Scott Fraser
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA; Translational Imaging Center, University of Southern California, Los Angeles, CA 90089, USA; Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Rong Lu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA; Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90033, USA; Department of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Keyue Shen
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA; Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90033, USA; USC Stem Cell, University of Southern California, Los Angeles, CA 90033, USA.
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81
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Yoo BC, Yadav NS, Orozco EM, Sakai H. Cas9/gRNA-mediated genome editing of yeast mitochondria and Chlamydomonas chloroplasts. PeerJ 2020; 8:e8362. [PMID: 31934513 PMCID: PMC6951285 DOI: 10.7717/peerj.8362] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/05/2019] [Indexed: 11/20/2022] Open
Abstract
We present a new approach to edit both mitochondrial and chloroplast genomes. Organelles have been considered off-limits to CRISPR due to their impermeability to most RNA and DNA. This has prevented applications of Cas9/gRNA-mediated genome editing in organelles while the tool has been widely used for engineering of nuclear DNA in a number of organisms in the last several years. To overcome the hurdle, we designed a new approach to enable organelle genome editing. The plasmids, designated "Edit Plasmids," were constructed with two expression cassettes, one for the expression of Cas9, codon-optimized for each organelle, under promoters specific to each organelle, and the other cassette for the expression of guide RNAs under another set of promoters specific to each organelle. In addition, Edit Plasmids were designed to carry the donor DNA for integration between two double-strand break sites induced by Cas9/gRNAs. Each donor DNA was flanked by the regions homologous to both ends of the integration site that were short enough to minimize spontaneous recombination events. Furthermore, the donor DNA was so modified that it did not carry functional gRNA target sites, allowing the stability of the integrated DNA without being excised by further Cas9/gRNAs activity. Edit Plasmids were introduced into organelles through microprojectile transformation. We confirmed donor DNA insertion at the target sites facilitated by homologous recombination only in the presence of Cas9/gRNA activity in yeast mitochondria and Chlamydomonas chloroplasts. We also showed that Edit Plasmids persist and replicate in mitochondria autonomously for several dozens of generations in the presence of the wild-type genomes. Finally, we did not find insertions and/or deletions at one of the Cas9 cleavage sites in Chloroplasts, which are otherwise hallmarks of Cas9/gRNA-mediated non-homologous end joining (NHEJ) repair events in nuclear DNA. This is consistent with previous reports of the lack of NHEJ repair system in most bacteria, which are believed to be ancestors of organelles. This is the first demonstration of CRISPR-mediated genome editing in both mitochondria and chloroplasts in two distantly related organisms. The Edit Plasmid approach is expected to open the door to engineer organelle genomes of a wide range of organisms in a precise fashion.
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82
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Park CK, Horton NC. Structures, functions, and mechanisms of filament forming enzymes: a renaissance of enzyme filamentation. Biophys Rev 2019; 11:927-994. [PMID: 31734826 PMCID: PMC6874960 DOI: 10.1007/s12551-019-00602-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
Filament formation by non-cytoskeletal enzymes has been known for decades, yet only relatively recently has its wide-spread role in enzyme regulation and biology come to be appreciated. This comprehensive review summarizes what is known for each enzyme confirmed to form filamentous structures in vitro, and for the many that are known only to form large self-assemblies within cells. For some enzymes, studies describing both the in vitro filamentous structures and cellular self-assembly formation are also known and described. Special attention is paid to the detailed structures of each type of enzyme filament, as well as the roles the structures play in enzyme regulation and in biology. Where it is known or hypothesized, the advantages conferred by enzyme filamentation are reviewed. Finally, the similarities, differences, and comparison to the SgrAI endonuclease system are also highlighted.
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Affiliation(s)
- Chad K. Park
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
| | - Nancy C. Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
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83
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Gabba M, Frallicciardi J, van 't Klooster J, Henderson R, Syga Ł, Mans R, van Maris AJA, Poolman B. Weak Acid Permeation in Synthetic Lipid Vesicles and Across the Yeast Plasma Membrane. Biophys J 2019; 118:422-434. [PMID: 31843263 PMCID: PMC6976801 DOI: 10.1016/j.bpj.2019.11.3384] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 11/10/2019] [Accepted: 11/14/2019] [Indexed: 12/29/2022] Open
Abstract
We present a fluorescence-based approach for determination of the permeability of small molecules across the membranes of lipid vesicles and living cells. With properly designed experiments, the method allows us to assess the membrane physical properties both in vitro and in vivo. We find that the permeability of weak acids increases in the order of benzoic > acetic > formic > lactic, both in synthetic lipid vesicles and the plasma membrane of Saccharomyces cerevisiae, but the permeability is much lower in yeast (one to two orders of magnitude). We observe a relation between the molecule permeability and the saturation of the lipid acyl chain (i.e., lipid packing) in the synthetic lipid vesicles. By analyzing wild-type yeast and a manifold knockout strain lacking all putative lactic acid transporters, we conclude that the yeast plasma membrane is impermeable to lactic acid on timescales up to ∼2.5 h.
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Affiliation(s)
- Matteo Gabba
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Jacopo Frallicciardi
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Joury van 't Klooster
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Ryan Henderson
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Łukasz Syga
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Robert Mans
- Department of Industrial Biotechnology, Delft University of Technology, Delft, the Netherlands
| | - Antonius J A van Maris
- Department of Industrial Biotechnology, Delft University of Technology, Delft, the Netherlands; Industrial Biotechnology Division, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands.
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84
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Kriner MA, Subramaniam AR. The serine transporter SdaC prevents cell lysis upon glucose depletion in Escherichia coli. Microbiologyopen 2019; 9:e960. [PMID: 31680488 PMCID: PMC7002108 DOI: 10.1002/mbo3.960] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/25/2019] [Accepted: 10/09/2019] [Indexed: 11/10/2022] Open
Abstract
The amino acid serine plays diverse metabolic roles, yet bacteria actively degrade exogenously provided serine via deamination to pyruvate. Serine deamination is thought to be a detoxification mechanism due to the ability of serine to inhibit several biosynthetic reactions, but this pathway remains highly active even in nutrient-replete conditions. While investigating the physiological roles of serine deamination in different growth conditions, we discovered that Escherichia coli cells lacking the sdaCB operon, which encodes the serine transporter SdaC and the serine deaminase SdaB, lyse upon glucose depletion in a medium containing no exogenous serine but all other amino acids and nucleobases. Unexpectedly, this lysis phenotype can be recapitulated by deleting sdaC alone and can be rescued by heterologous expression of SdaC. Lysis of ΔsdaC cells can be prevented by omitting glycine from the medium, inhibiting the glycine cleavage system, or by increasing alanine availability. Together, our results reveal that the serine transporter SdaC plays a critical role in maintaining amino acid homeostasis during shifts in nutrient availability in E. coli.
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Affiliation(s)
- Michelle A Kriner
- Basic Sciences Division and Computational Biology Section of the Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Arvind R Subramaniam
- Basic Sciences Division and Computational Biology Section of the Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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85
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Parui PP, Sarakar Y, Majumder R, Das S, Yang H, Yasuhara K, Hirota S. Determination of proton concentration at cardiolipin-containing membrane interfaces and its relation with the peroxidase activity of cytochrome c. Chem Sci 2019; 10:9140-9151. [PMID: 31827756 PMCID: PMC6889831 DOI: 10.1039/c9sc02993a] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/03/2019] [Indexed: 01/04/2023] Open
Abstract
The activities of biomolecules are affected by the proton concentrations at biological membranes. Here, we succeeded in evaluating the interface proton concentration (-log[H+] defined as pH') of cardiolipin (CL)-enriched membrane models of the inner mitochondrial membrane (IMM) using a spiro-rhodamine-glucose molecule (RHG). According to fluorescence microscopy and 1H-NMR studies, RHG interacted with the Stern layer of the membrane. The acid/base equilibrium of RHG between its protonated open form (o-RHG) and deprotonated closed spiro-form (c-RHG) at the membrane interface was monitored with UV-vis absorption and fluorescence spectra. The interface pH' of 25% cardiolipin (CL)-containing large unilamellar vesicles (LUVs), which possess similar lipid properties to those of the IMM, was estimated to be ∼3.9, when the bulk pH was similar to the mitochondrial intermembrane space pH (6.8). However, for the membranes containing mono-anionic lipids, the interface pH' was estimated to be ∼5.3 at bulk pH 6.8, indicating that the local negative charges of the lipid headgroups in the lipid membranes are responsible for the deviation of the interface pH' from the bulk pH. The peroxidase activity of cyt c increased 5-7 fold upon lowering the pH to 3.9-4.3 or adding CL-containing (10-25% of total lipids) LUVs compared to that at bulk pH 6.8, indicating that the pH' decrease at the IMM interface from the bulk pH enhances the peroxidase activity of cyt c. The peroxidase activity of cyt c at the membrane interface of tetraoleoyl CL (TOCL)-enriched (50% of total lipids) LUVs was higher than that estimated from the interface pH', while the peroxidase activity was similar to that estimated from the interface pH' for tetramyristoyl CL (TMCL)-enriched LUVs, supporting the hypothesis that when interacting with TOCL (not TMCL), cyt c opens the heme crevice to substrates. The present simple methodology allows us to estimate the interface proton concentrations of complex biological membranes.
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Affiliation(s)
- Partha Pratim Parui
- Department of Chemistry , Jadavpur University , Kolkata 700032 , India . ; ; Tel: +91-9433490492
- Division of Materials Science , Nara Institute of Science and Technology , Nara 630-0192 , Japan
| | - Yeasmin Sarakar
- Department of Chemistry , Jadavpur University , Kolkata 700032 , India . ; ; Tel: +91-9433490492
| | - Rini Majumder
- Department of Chemistry , Jadavpur University , Kolkata 700032 , India . ; ; Tel: +91-9433490492
| | - Sanju Das
- Department of Chemistry , Jadavpur University , Kolkata 700032 , India . ; ; Tel: +91-9433490492
- Department of Chemistry , Maulana Azad College , Kolkata 700013 , India
| | - Hongxu Yang
- Division of Materials Science , Nara Institute of Science and Technology , Nara 630-0192 , Japan
| | - Kazuma Yasuhara
- Division of Materials Science , Nara Institute of Science and Technology , Nara 630-0192 , Japan
| | - Shun Hirota
- Division of Materials Science , Nara Institute of Science and Technology , Nara 630-0192 , Japan
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86
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Real time quantification of intracellular nickel using genetically encoded FRET-based nanosensor. Int J Biol Macromol 2019; 138:648-657. [DOI: 10.1016/j.ijbiomac.2019.07.115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/13/2019] [Accepted: 07/19/2019] [Indexed: 12/19/2022]
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87
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Soleja N, Jairajpuri MA, Queen A, Mohsin M. Genetically encoded FRET-based optical sensor for Hg 2+ detection and intracellular imaging in living cells. J Ind Microbiol Biotechnol 2019; 46:1669-1683. [PMID: 31531745 DOI: 10.1007/s10295-019-02235-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 09/05/2019] [Indexed: 12/31/2022]
Abstract
Due to the potential toxicity of mercury, there is an immediate need to understand its uptake, transport and flux within living cells. Conventional techniques used to analyze Hg2+ are invasive, involve high cost and are less sensitive. In the present study, a highly efficient genetically encoded mercury FRET sensor (MerFS) was developed to measure the cellular dynamics of Hg2+ at trace level in real time. To construct MerFS, the periplasmic mercury-binding protein MerP was sandwiched between enhanced cyan fluorescent protein (ECFP) and venus. MerFS is pH stable, offers a measurable fluorescent signal and binds to Hg2+ with high sensitivity and selectivity. Mutant MerFS-51 binds with an apparent affinity (Kd) of 5.09 × 10-7 M, thus providing a detection range for Hg2+ quantification between 0.210 µM and 1.196 µM. Furthermore, MerFS-51 was targeted to Escherichia coli (E. coli), yeast and human embryonic kidney (HEK)-293T cells that allowed dynamic measurement of intracellular Hg2+ concentration with a highly responsive saturation curve, proving its potential application in cellular systems.
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Affiliation(s)
- Neha Soleja
- Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India
| | | | - Aarfa Queen
- Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025, India
| | - Mohd Mohsin
- Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India.
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88
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Erv14 cargo receptor participates in regulation of plasma-membrane potential, intracellular pH and potassium homeostasis via its interaction with K+-specific transporters Trk1 and Tok1. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:1376-1388. [DOI: 10.1016/j.bbamcr.2019.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 05/21/2019] [Accepted: 05/23/2019] [Indexed: 12/31/2022]
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89
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Soleja N, Manzoor O, Khan P, Mohsin M. Engineering genetically encoded FRET-based nanosensors for real time display of arsenic (As 3+) dynamics in living cells. Sci Rep 2019; 9:11240. [PMID: 31375744 PMCID: PMC6677752 DOI: 10.1038/s41598-019-47682-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/12/2019] [Indexed: 02/07/2023] Open
Abstract
Arsenic poisoning has been a major concern that causes severe toxicological damages. Therefore, intricate and inclusive understanding of arsenic flux rates is required to ascertain the cellular concentration and establish the carcinogenetic mechanism of this toxicant at real time. The lack of sufficiently sensitive sensing systems has hampered research in this area. In this study, we constructed a fluorescent resonance energy transfer (FRET)-based nanosensor, named SenALiB (Sensor for Arsenic Linked Blackfoot disease) which contains a metalloregulatory arsenic-binding protein (ArsR) as the As3+ sensing element inserted between the FRET pair enhanced cyan fluorescent protein (ECFP) and Venus. SenALiB takes advantage of the ratiometic FRET readout which measures arsenic with high specificity and selectivity. SenALiB offers rapid detection response, is stable to pH changes and provides highly accurate, real-time optical readout in cell-based assays. SenALiB-676n with a binding constant (Kd) of 0.676 × 10−6 M is the most efficient affinity mutant and can be a versatile tool for dynamic measurement of arsenic concentration in both prokaryotes and eukaryotes in vivo in a non-invasive manner.
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Affiliation(s)
- Neha Soleja
- Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Ovais Manzoor
- Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Parvez Khan
- Centre for Interdisciplinary Research in Basic Science, Jamia Millia Islamia, New Delhi, 110025, India
| | - Mohd Mohsin
- Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025, India.
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90
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Villanueva R, Romero-Tamayo S, Laplaza R, Martínez-Olivan J, Velázquez-Campoy A, Sancho J, Ferreira P, Medina M. Redox- and Ligand Binding-Dependent Conformational Ensembles in the Human Apoptosis-Inducing Factor Regulate Its Pro-Life and Cell Death Functions. Antioxid Redox Signal 2019; 30:2013-2029. [PMID: 30450916 DOI: 10.1089/ars.2018.7658] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Aims: The human apoptosis-inducing factor (hAIF) supports OXPHOS biogenesis and programmed cell death, with missense mutations producing neurodegenerative phenotypes. hAIF senses the redox environment of cellular compartments, stabilizing a charge transfer complex (CTC) dimer that modulates the protein interaction network. In this context, we aimed to evaluate the subcellular pH, CTC formation, and pathogenic mutations effects on hAIF stability, and a thermal denaturation high-throughput screening (HTS) assay to discover AIF binders. Results: Apoptotic hAIFΔ1-101 is not stable at intermembrane mitochondrial space (IMS) pH, but the 77-101 residues confer stability to the mitochondrial isoform. hAIF and its CTC populate different conformational ensembles with redox switch to the CTC producing a less stable and compact protein. The pathogenic G308E, ΔR201, and E493V mutations modulate hAIF stability; particularly, ΔR201 causes a population shift to a less stable conformation that remodels active site structure and dynamics. We have identified new molecules that modulate the hAIF reduced nicotinamide adenine dinucleotide (NADH)/oxidized nicotinamide adenine dinucleotide (NAD+) association/dissociation equilibrium and regulate its catalytic efficiency. Innovation: Biophysical methods allow evaluating the regulation of hAIF functional ensembles and to develop an HTS assay to discover small molecules that might modulate hAIF stability and activities. Conclusions: The mitochondrial soluble 54-77 portion stabilizes hAIF at the IMS pH. NADH-redox-linked conformation changes course with strong NAD+ binding and protein dimerization, but they produce a negative impact in overall hAIF stability. Loss of functionality in the R201 deletion is due to distortion of the active site architecture. We report molecules that may serve as leads in the development of hAIF bioactive compounds.
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Affiliation(s)
- Raquel Villanueva
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - Silvia Romero-Tamayo
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - Ruben Laplaza
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain.,2 Departamento de Química Física, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Juan Martínez-Olivan
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - Adrián Velázquez-Campoy
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain.,3 Fundación ARAID, Diputación General de Aragón, Zaragoza, Spain.,4 Aragon Institute for Health Research (IIS Aragon), Zaragoza, Spain.,5 Biomedical Research Networking Centre for Liver and Digestive Diseases (CIBERehd), Madrid, Spain
| | - Javier Sancho
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain.,4 Aragon Institute for Health Research (IIS Aragon), Zaragoza, Spain
| | - Patricia Ferreira
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - Milagros Medina
- 1 Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
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91
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Genomewide Elucidation of Drug Resistance Mechanisms for Systemically Used Antifungal Drugs Amphotericin B, Caspofungin, and Voriconazole in the Budding Yeast. Antimicrob Agents Chemother 2019; 63:AAC.02268-18. [PMID: 31209012 DOI: 10.1128/aac.02268-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 06/03/2019] [Indexed: 12/16/2022] Open
Abstract
There are only a few antifungal drugs used systemically in treatment, and invasive fungal infections that are resistant to these drugs are an emerging problem in health care. In this study, we performed a high-copy-number genomic DNA (gDNA) library screening to find and characterize genes that reduce susceptibility to amphotericin B, caspofungin, and voriconazole in Saccharomyces cerevisiae We identified the PDR16 and PMP3 genes for amphotericin B, the RMD9 and SWH1 genes for caspofungin, and the MRS3 and TRI1 genes for voriconazole. The deletion mutants for PDR16 and PMP3 were drug susceptible, but the other mutants had no apparent susceptibility. Quantitative-PCR analyses suggested that the corresponding drugs upregulated expression of the PDR16, PMP3, SWH1, and MRS3 genes. To further characterize these genes, we also profiled the global expression patterns of the cells after treatment with the antifungals and determined the genes and paths that were up- or downregulated. We also cloned Candida albicans homologs of the PDR16, PMP3, MRS3, and TRI1 genes and expressed them in S. cerevisiae Heterologous expression of Candida homologs also provided reduced drug susceptibility to the budding yeast cells. Our analyses suggest the involvement of new genes in antifungal drug resistance.
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92
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Vall-Llaura N, Mir N, Garrido L, Vived C, Cabiscol E. Redox control of yeast Sir2 activity is involved in acetic acid resistance and longevity. Redox Biol 2019; 24:101229. [PMID: 31153040 PMCID: PMC6543126 DOI: 10.1016/j.redox.2019.101229] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/10/2019] [Accepted: 05/19/2019] [Indexed: 01/07/2023] Open
Abstract
Yeast Sir2 is an NAD-dependent histone deacetylase related to oxidative stress and aging. In a previous study, we showed that Sir2 is regulated by S-glutathionylation of key cysteine residues located at the catalytic domain. Mutation of these residues results in strains with increased resistance to disulfide stress. In the present study, these mutant cells were highly resistant to acetic acid and had an increased chronological life span. Mutant cells had increased acetyl-CoA synthetase activity, which converts acetic acid generated by yeast metabolism to acetyl.CoA. This could explain the acetic acid resistance and lower levels of this toxic acid in the extracellular media during aging. Increased acetyl-CoA levels would raise lipid droplets, a source of energy during aging, and fuel glyoxylate-dependent gluconeogenesis. The key enzyme of this pathway, phosphoenolpyruvate carboxykinase (Pck1), showed increased activity in these Sir2 mutant cells during aging. Sir2 activity decreased when cells shifted to the diauxic phase in the mutant strains, compared to the WT strain. Since Pck1 is inactivated through Sir2-dependent deacetylation, the decline in Sir2 activity explained the rise in Pck1 activity. As a consequence, storage of sugars such as trehalose would increase. We conclude that extended longevity observed in the mutants was a combination of increased lipid droplets and trehalose, and decreased acetic acid in the extracellular media. These results offer a deeper understanding of the redox regulation of Sir2 in acetic acid resistance, which is relevant in some food and industrial biotechnology and also in the metabolism associated to calorie restriction, aging and pathologies such as diabetes.
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Affiliation(s)
- Núria Vall-Llaura
- Department de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Catalonia, Spain.
| | - Noèlia Mir
- Department de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Catalonia, Spain.
| | - Lourdes Garrido
- Department de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Catalonia, Spain.
| | - Celia Vived
- Department de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Catalonia, Spain.
| | - Elisa Cabiscol
- Department de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Catalonia, Spain.
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93
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Lyu X, Zhao G, Ng KR, Mark R, Chen WN. Metabolic Engineering of Saccharomyces cerevisiae for De Novo Production of Kaempferol. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:5596-5606. [PMID: 30957490 DOI: 10.1021/acs.jafc.9b01329] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Kaempferol is a polyphenolic compound with various reported health benefits and thus harbors considerable potential for food-engineering applications. In this study, a high-yield kaempferol-producing cell factory was constructed by multiple strategies, including gene screening, elimination of the phenylethanol biosynthetic branch, optimizing the core flavonoid synthetic pathway, supplementation of precursor PEP/E4P, and mitochondrial engineering of F3H and FLS. A total of 86 mg/L of kaempferol was achieved in strain YL-4, to date the highest production titer in yeast. Furthermore, a coculture system and supplementation of surfactants were investigated, to relieve the metabolic burden as well as the low solubility/possible transport limitations of flavonoids, respectively. In the coculture system, the whole pathway was divided across two strains, resulting in 50% increased cell growth. Meanwhile, supplementation of Tween 80 in our engineered strains yielded 220 mg/L of naringenin and 200 mg/L of mixed flavonoids-among the highest production titer reported via de novo production in yeast.
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Affiliation(s)
- Xiaomei Lyu
- School of Chemical and Biomedical Engineering, College of Engineering , Nanyang Technological University , 62 Nanyang Drive , Singapore 637459 , Singapore
| | - Guili Zhao
- School of Chemical and Biomedical Engineering, College of Engineering , Nanyang Technological University , 62 Nanyang Drive , Singapore 637459 , Singapore
| | - Kuan Rei Ng
- School of Chemical and Biomedical Engineering, College of Engineering , Nanyang Technological University , 62 Nanyang Drive , Singapore 637459 , Singapore
| | - Rita Mark
- School of Chemical and Biomedical Engineering, College of Engineering , Nanyang Technological University , 62 Nanyang Drive , Singapore 637459 , Singapore
| | - Wei Ning Chen
- School of Chemical and Biomedical Engineering, College of Engineering , Nanyang Technological University , 62 Nanyang Drive , Singapore 637459 , Singapore
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94
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Muid KA, Kimyon Ö, Reza SH, Karakaya HC, Koc A. Characterization of long living yeast deletion mutants that lack mitochondrial metabolism genes DSS1, PPA2 and AFG3. Gene 2019; 706:172-180. [PMID: 31082499 DOI: 10.1016/j.gene.2019.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 04/15/2019] [Accepted: 05/01/2019] [Indexed: 02/06/2023]
Abstract
Molecular mechanisms of aging and longevity are still mostly unknown. Mitochondria play central roles in cellular metabolism and aging. In this study, we identified three deletion mutants of mitochondrial metabolism genes (ppa2∆, dss1∆, and afg3∆) that live longer than wild-type cells. These long-lived cells harbored significantly decreased amount of mitochondrial DNA (mtDNA) and reactive oxygen species (ROS). Compared to the serpentine nature of wild-type mitochondria, a different dynamics and distribution pattern of mitochondria were observed in the mutants. Both young and old long-lived cells produced relatively low but adequate levels of ATP for cellular activities. The status of the retrograde signaling was checked by expression of CIT2 gene and found activated in long-lived mutants. The mutant cells were also profiled for their gene expression patterns, and genes that were differentially regulated were determined. All long-lived cells comprised similar pleiotropic phenotype regarding mitochondrial dynamics and functions. Thus, this study suggests that DSS1, PPA2, and AFG3 genes modulate the lifespan by altering the mitochondrial morphology and functions.
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Affiliation(s)
- K A Muid
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430 Urla, Izmir, Turkey
| | - Önder Kimyon
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430 Urla, Izmir, Turkey
| | - Shahadat Hasan Reza
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430 Urla, Izmir, Turkey
| | - Huseyin Caglar Karakaya
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430 Urla, Izmir, Turkey
| | - Ahmet Koc
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430 Urla, Izmir, Turkey; Inonu University, Medical School, Department of Medical Biology and Genetics, Battalgazi, Malatya, Turkey.
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95
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Periplanetasin-4, a novel antimicrobial peptide from the cockroach, inhibits communications between mitochondria and vacuoles. Biochem J 2019; 476:1267-1284. [DOI: 10.1042/bcj20180933] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/04/2019] [Accepted: 04/08/2019] [Indexed: 12/16/2022]
Abstract
Abstract
Communications between various organelle–organelles play an essential role in cell survival. The cross-talk between mitochondria and vacuoles comes up with the vital roles of the intercompartmental process. In this study, we found a couple of cell death features, membrane damage, and apoptosis using antimicrobial peptide from American Cockroach. Periplanetasin-4 (LRHKVYGYCVLGP-NH2) is a 13-mer peptide derived from Periplaneta americana and exhibits phosphatidylserine exposure and caspase activation without DNA fragmentation. Apoptotic features without DNA damage provide evidence that this peptide did not interact with DNA directly and exhibited dysfunction of mitochondria and vacuoles. Superoxide radicals were generated from mitochondria and converted to hydrogen peroxide. Despite the enhancement of catalase and total glutathione contents, oxidative damage disrupted intracellular contents. Periplanetasin-4 induced cell death associated with the production of superoxide radicals, calcium uptake in mitochondria and disorder of vacuoles, such as increased permeability and alkalization. While calcium movement from vacuoles to the mitochondria occurred, the cross-talk with these organelles proceeded and the inherent functionality was impaired. To sum up, periplanetasin-4 stimulates superoxide signal along with undermining the mitochondrial functions and interfering in communication with vacuoles.
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96
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Soleja N, Manzoor O, Nandal P, Mohsin M. FRET-based nanosensors for monitoring and quantification of alcohols in living cells. Org Biomol Chem 2019; 17:2413-2422. [PMID: 30735222 DOI: 10.1039/c8ob03208d] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Odorants constitute a small and chemically diverse group of molecules with ethanol functioning as a key odorant that induces reproductive toxicity and adverse chronic effects on the liver. Analytical tools designed so far for the detection of odorant molecules are relatively invasive. Therefore, a tool that can measure the corresponding rate changes of ethanol concentration in real-time is highly desirable. Here in this work, we report a genetically encoded fluorescence resonance energy transfer (FRET)-based nanosensor for in vivo quantification of ethanol at the cellular level with high spatial and temporal resolution. A human odorant-binding protein (hOBPIIa) was flanked by fluorescent proteins ECFP (Enhanced Cyan Fluorescent Protein) and Venus at the N- and C-terminus respectively. The constructed FRET nanosensor was named the fluorescent indicator protein for odorants (FLIPO). FLIPO allows in vitro and in vivo determination of FRET changes in a concentration-dependent manner. The developed nanosensor is highly specific to ethanol, stable to pH changes and provides rapid detection rate response. FLIPO-42 is the most efficient nanosensor created that measures ethanol with an apparent affinity (Kd) of 4.16 μM and covers the physiological range of 500 nM to 12 μM ethanol measurement. FLIPO-42 can measure ethanol dynamics in bacterial, yeast and mammalian cells non-invasively in real time which proves its efficacy as a sensing device in both prokaryotic and eukaryotic systems. Taken together, a prototype for a set of nanosensors was established, potentially enabling the monitoring of dynamic changes of ethanol and investigate its uptake and metabolism with subcellular resolution in vivo and ex vivo. Furthermore, the advent of a set of novel nanosensors will provide us with the tools for numerous medical, scientific, industrial and environmental applications which would help to illuminate their role in biological systems.
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Affiliation(s)
- Neha Soleja
- Department of Biosciences, Jamia Millia Islamia, New Delhi-110025, India.
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97
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Botman D, de Groot DH, Schmidt P, Goedhart J, Teusink B. In vivo characterisation of fluorescent proteins in budding yeast. Sci Rep 2019; 9:2234. [PMID: 30783202 PMCID: PMC6381139 DOI: 10.1038/s41598-019-38913-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 12/14/2018] [Indexed: 02/05/2023] Open
Abstract
Fluorescent proteins (FPs) are widely used in many organisms, but are commonly characterised in vitro. However, the in vitro properties may poorly reflect in vivo performance. Therefore, we characterised 27 FPs in vivo using Saccharomyces cerevisiae as model organism. We linked the FPs via a T2A peptide to a control FP, producing equimolar expression of the 2 FPs from 1 plasmid. Using this strategy, we characterised the FPs for brightness, photostability, photochromicity and pH-sensitivity, achieving a comprehensive in vivo characterisation. Many FPs showed different in vivo properties compared to existing in vitro data. Additionally, various FPs were photochromic, which affects readouts due to complex bleaching kinetics. Finally, we codon optimized the best performing FPs for optimal expression in yeast, and found that codon-optimization alters FP characteristics. These FPs improve experimental signal readout, opening new experimental possibilities. Our results may guide future studies in yeast that employ fluorescent proteins.
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Affiliation(s)
- Dennis Botman
- Systems Bioinformatics/AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Daan Hugo de Groot
- Systems Bioinformatics/AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Phillipp Schmidt
- Systems Bioinformatics/AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Joachim Goedhart
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Bas Teusink
- Systems Bioinformatics/AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.
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98
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Nguyen PTM, Ishiwata-Kimata Y, Kimata Y. Monitoring ADP/ATP ratio in yeast cells using the fluorescent-protein reporter PercevalHR. Biosci Biotechnol Biochem 2019; 83:824-828. [PMID: 30704350 DOI: 10.1080/09168451.2019.1574204] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PercevalHR (Perceval High Resolution) is an artificially designed fluorescent protein, which changes its excitation spectrum based on the ADP/ATP ratio of the environment. Here we demonstrated that PercevalHR can be used for monitoring energy status of Saccharomyces cerevisiae cells, which are affected by diauxic shift and mitochondria inhibition, in a non-invasive and non-destructive manner.
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Affiliation(s)
- Phuong Thi Mai Nguyen
- a Graduate School of Science and Technology , Nara Institute of Science and Technology , Nara , Japan
| | - Yuki Ishiwata-Kimata
- a Graduate School of Science and Technology , Nara Institute of Science and Technology , Nara , Japan
| | - Yukio Kimata
- a Graduate School of Science and Technology , Nara Institute of Science and Technology , Nara , Japan
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99
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Stynen B, Abd-Rabbo D, Kowarzyk J, Miller-Fleming L, Aulakh SK, Garneau P, Ralser M, Michnick SW. Changes of Cell Biochemical States Are Revealed in Protein Homomeric Complex Dynamics. Cell 2018; 175:1418-1429.e9. [PMID: 30454649 PMCID: PMC6242466 DOI: 10.1016/j.cell.2018.09.050] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 09/04/2018] [Accepted: 09/24/2018] [Indexed: 01/22/2023]
Abstract
We report here a simple and global strategy to map out gene functions and target pathways of drugs, toxins, or other small molecules based on "homomer dynamics" protein-fragment complementation assays (hdPCA). hdPCA measures changes in self-association (homomerization) of over 3,500 yeast proteins in yeast grown under different conditions. hdPCA complements genetic interaction measurements while eliminating the confounding effects of gene ablation. We demonstrate that hdPCA accurately predicts the effects of two longevity and health span-affecting drugs, the immunosuppressant rapamycin and the type 2 diabetes drug metformin, on cellular pathways. We also discovered an unsuspected global cellular response to metformin that resembles iron deficiency and includes a change in protein-bound iron levels. This discovery opens a new avenue to investigate molecular mechanisms for the prevention or treatment of diabetes, cancers, and other chronic diseases of aging.
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Affiliation(s)
- Bram Stynen
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Diala Abd-Rabbo
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada; Centre Robert-Cedergren, Bio-Informatique et Génomique, Université de Montréal, C.P. 6128, Succursale centre-ville, Montréal, QC H3C 3J7, Canada
| | - Jacqueline Kowarzyk
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Leonor Miller-Fleming
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Simran Kaur Aulakh
- Molecular Biology of Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Philippe Garneau
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Markus Ralser
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK; Molecular Biology of Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Biochemistry, Charité University Medicine, Berlin, Germany
| | - Stephen W Michnick
- Département de Biochimie, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada; Centre Robert-Cedergren, Bio-Informatique et Génomique, Université de Montréal, C.P. 6128, Succursale centre-ville, Montréal, QC H3C 3J7, Canada.
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100
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Reifenrath M, Bauer M, Oreb M, Boles E. Bacterial bifunctional chorismate mutase-prephenate dehydratase PheA increases flux into the yeast phenylalanine pathway and improves mandelic acid production. Metab Eng Commun 2018; 7:e00079. [PMID: 30370221 PMCID: PMC6199770 DOI: 10.1016/j.mec.2018.e00079] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 08/21/2018] [Accepted: 09/17/2018] [Indexed: 01/29/2023] Open
Abstract
Mandelic acid is an important aromatic fine chemical and is currently mainly produced via chemical synthesis. Recently, mandelic acid production was achieved by microbial fermentations using engineered Escherichia coli and Saccharomyces cerevisiae expressing heterologous hydroxymandelate synthases (hmaS). The best-performing strains carried a deletion of the gene encoding the first enzyme of the tyrosine biosynthetic pathway and therefore were auxotrophic for tyrosine. This was necessary to avoid formation of the competing intermediate hydroxyphenylpyruvate, the preferred substrate for HmaS, which would have resulted in the predominant production of hydroxymandelic acid. However, feeding tyrosine to the medium would increase fermentation costs. In order to engineer a tyrosine prototrophic mandelic acid-producing S. cerevisiae strain, we tested three strategies: (1) rational engineering of the HmaS active site for reduced binding of hydroxyphenylpyruvate, (2) compartmentalization of the mandelic acid biosynthesis pathway by relocating HmaS together with the two upstream enzymes chorismate mutase Aro7 and prephenate dehydratase Pha2 into mitochondria or peroxisomes, and (3) utilizing a feedback-resistant version of the bifunctional E. coli enzyme PheA (PheAfbr) in an aro7 deletion strain. PheA has both chorismate mutase and prephenate dehydratase activity. Whereas the enzyme engineering approaches were only successful in respect to reducing the preference of HmaS for hydroxyphenylpyruvate but not in increasing mandelic acid titers, we could show that strategies (2) and (3) significantly reduced hydroxymandelic acid production in favor of increased mandelic acid production, without causing tyrosine auxotrophy. Using the bifunctional enzyme PheAfbr turned out to be the most promising strategy, and mandelic acid production could be increased 12-fold, yielding titers up to 120 mg/L. Moreover, our results indicate that utilizing PheAfbr also shows promise for other industrial applications with S. cerevisiae that depend on a strong flux into the phenylalanine biosynthetic pathway. Increased mandelic acid production in tyrosine prototrophic S. cerevisiae. Bifunctional E. coli enzyme PheA increases flux into yeast phenylalanine branch. PheA allows mandelic acid production in prototrophic S. cerevisiae. Compartmentalized mandelic acid production in yeast mitochondria/peroxisomes.
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Affiliation(s)
- Mara Reifenrath
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Maren Bauer
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
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