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Ali SA, Songdech P, Samakkarn W, Duangphakdee O, Soontorngun N. New regulatory role of Znf1 in transcriptional control of pentose phosphate pathway and ATP synthesis for enhanced isobutanol and acid tolerance. Yeast 2024; 41:401-417. [PMID: 38708451 DOI: 10.1002/yea.3940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 02/20/2024] [Accepted: 04/15/2024] [Indexed: 05/07/2024] Open
Abstract
To develop a cost-effective microbial cell factory for the production of biofuels and biochemicals, an understanding of tolerant mechanisms is vital for the construction of robust host strains. Here, we characterized a new function of a key metabolic transcription factor named Znf1 and its involvement in stress response in Saccharomyces cerevisiae to enhance tolerance to advanced biofuel, isobutanol. RNA-sequencing analysis of the wild-type versus the znf1Δ deletion strains in glucose revealed a new role for transcription factor Znf1 in the pentose phosphate pathway (PPP) and energy generation. The gene expression analysis confirmed that isobutanol induces an adaptive cell response, resulting in activation of ATP1-3 and COX6 expression. These genes were Znf1 targets that belong to the electron transport chain, important to produce ATPs. Znf1 also activated PPP genes, required for the generation of key amino acids, cellular metabolites, and maintenance of NADP/NADPH redox balance. In glucose, Znf1 also mediated the upregulation of valine biosynthetic genes of the Ehrlich pathway, namely ILV3, ILV5, and ARO10, associated with the generation of key intermediates for isobutanol production. Using S. cerevisiae knockout collection strains, cells with deleted transcriptional regulatory gene ZNF1 or its targets displayed hypersensitivity to isobutanol and acid inhibitors; in contrast, overexpression of ZNF1 enhanced cell survival. Thus, the transcription factor Znf1 functions in the maintenance of energy homeostasis and redox balance at various checkpoints of yeast metabolic pathways. It ensures the rapid unwiring of gene transcription in response to toxic products/by-products generated during biofuel production. Importantly, we provide a new approach to enhance strain tolerance during the conversion of glucose to biofuels.
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Affiliation(s)
- Syed Azhar Ali
- Excellent Research Laboratory for Yeast Innovation, School of Bioresources and Technology, Division of Biochemical Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Pattanan Songdech
- Excellent Research Laboratory for Yeast Innovation, School of Bioresources and Technology, Division of Biochemical Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Wiwan Samakkarn
- Excellent Research Laboratory for Yeast Innovation, School of Bioresources and Technology, Division of Biochemical Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Orawan Duangphakdee
- Native Honeybee and Pollinator Research Center, King Mongkut's University of Technology Thonburi, Ratchaburi, Thailand
| | - Nitnipa Soontorngun
- Excellent Research Laboratory for Yeast Innovation, School of Bioresources and Technology, Division of Biochemical Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
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Martinez KP, Gasmi N, Jeronimo C, Klimova N, Robert F, Turcotte B. Yeast zinc cluster transcription factors involved in the switch from fermentation to respiration show interdependency for DNA binding revealing a novel type of DNA recognition. Nucleic Acids Res 2024; 52:2242-2259. [PMID: 38109318 PMCID: PMC10954478 DOI: 10.1093/nar/gkad1185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 11/22/2023] [Accepted: 11/29/2023] [Indexed: 12/20/2023] Open
Abstract
In budding yeast, fermentation is the most important pathway for energy production. Under low-glucose conditions, ethanol is used for synthesis of this sugar requiring a shift to respiration. This process is controlled by the transcriptional regulators Cat8, Sip4, Rds2 and Ert1. We characterized Gsm1 (glucose starvation modulator 1), a paralog of Rds2 and Ert1. Genome-wide analysis showed that Gsm1 has a DNA binding profile highly similar to Rds2. Binding of Gsm1 and Rds2 is interdependent at the gluconeogenic gene FBP1. However, Rds2 is required for Gsm1 to bind at other promoters but not the reverse. Gsm1 and Rds2 also bind to DNA independently of each other. Western blot analysis revealed that Rds2 controls expression of Gsm1. In addition, we showed that the DNA binding domains of Gsm1 and Rds2 bind cooperatively in vitro to the FBP1 promoter. In contrast, at the HAP4 gene, Ert1 cooperates with Rds2 for DNA binding. Mutational analysis suggests that Gsm1/Rds2 and Ert1/Rds2 bind to short common DNA stretches, revealing a novel mode of binding for this class of factors. Two-point mutations in a HAP4 site convert it to a Gsm1 binding site. Thus, Rds2 controls binding of Gsm1 at many promoters by two different mechanisms: regulation of Gsm1 levels and increased DNA binding by formation of heterodimers.
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Affiliation(s)
- Karla Páez Martinez
- Department of Medicine, McGill University Health Centre, 1001 Boul. Décarie, Room E02.7212, Montréal, QC H4A 3J1, Canada
| | - Najla Gasmi
- Department of Biochemistry, McGill University, 1001 Boul. Décarie, Room E02.7212, Montréal, QC H4A 3J1, Canada
| | - Célia Jeronimo
- Institut de recherches cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Natalia Klimova
- Department of Medicine, McGill University Health Centre, 1001 Boul. Décarie, Room E02.7212, Montréal, QC H4A 3J1, Canada
| | - François Robert
- Institut de recherches cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada
- Département de Médecine, Faculté de Médecine, Université de Montréal, 2900 Boul. Édouard-Montpetit, Montréal, QC H3T 1J4, Canada
| | - Bernard Turcotte
- Department of Medicine, McGill University Health Centre, 1001 Boul. Décarie, Room E02.7212, Montréal, QC H4A 3J1, Canada
- Department of Biochemistry, McGill University, 1001 Boul. Décarie, Room E02.7212, Montréal, QC H4A 3J1, Canada
- Department of Microbiology and Immunology, McGill University, 1001 Boul. Décarie, Room E02.7212, Montréal, QC H4A 3J1, Canada
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Songdech P, Butkinaree C, Yingchutrakul Y, Promdonkoy P, Runguphan W, Soontorngun N. Increased production of isobutanol from xylose through metabolic engineering of Saccharomyces cerevisiae overexpressing transcription factor Znf1 and exogenous genes. FEMS Yeast Res 2024; 24:foae006. [PMID: 38331422 PMCID: PMC10878408 DOI: 10.1093/femsyr/foae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 01/21/2024] [Accepted: 02/07/2024] [Indexed: 02/10/2024] Open
Abstract
Only trace amount of isobutanol is produced by the native Saccharomyces cerevisiae via degradation of amino acids. Despite several attempts using engineered yeast strains expressing exogenous genes, catabolite repression of glucose must be maintained together with high activity of downstream enzymes, involving iron-sulfur assimilation and isobutanol production. Here, we examined novel roles of nonfermentable carbon transcription factor Znf1 in isobutanol production during xylose utilization. RNA-seq analysis showed that Znf1 activates genes in valine biosynthesis, Ehrlich pathway and iron-sulfur assimilation while coupled deletion or downregulated expression of BUD21 further increased isobutanol biosynthesis from xylose. Overexpression of ZNF1 and xylose-reductase/dehydrogenase (XR-XDH) variants, a xylose-specific sugar transporter, xylulokinase, and enzymes of isobutanol pathway in the engineered S. cerevisiae pho13gre3Δ strain resulted in the superb ZNXISO strain, capable of producing high levels of isobutanol from xylose. The isobutanol titer of 14.809 ± 0.400 g/L was achieved, following addition of 0.05 g/L FeSO4.7H2O in 5 L bioreactor. It corresponded to 155.88 mg/g xylose consumed and + 264.75% improvement in isobutanol yield. This work highlights a new regulatory control of alternative carbon sources by Znf1 on various metabolic pathways. Importantly, we provide a foundational step toward more sustainable production of advanced biofuels from the second most abundant carbon source xylose.
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Affiliation(s)
- Pattanan Songdech
- Excellent Research Laboratory for Yeast Innovation, Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok 10150, Thailand
| | - Chutikarn Butkinaree
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani 12120, Thailand
| | - Yodying Yingchutrakul
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani 12120, Thailand
| | - Peerada Promdonkoy
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani 12120, Thailand
| | - Weerawat Runguphan
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani 12120, Thailand
| | - Nitnipa Soontorngun
- Excellent Research Laboratory for Yeast Innovation, Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok 10150, Thailand
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Hackley RK, Vreugdenhil-Hayslette A, Darnell CL, Schmid AK. A conserved transcription factor controls gluconeogenesis via distinct targets in hypersaline-adapted archaea with diverse metabolic capabilities. PLoS Genet 2024; 20:e1011115. [PMID: 38227606 PMCID: PMC10817205 DOI: 10.1371/journal.pgen.1011115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 01/26/2024] [Accepted: 12/22/2023] [Indexed: 01/18/2024] Open
Abstract
Timely regulation of carbon metabolic pathways is essential for cellular processes and to prevent futile cycling of intracellular metabolites. In Halobacterium salinarum, a hypersaline adapted archaeon, a sugar-sensing TrmB family protein controls gluconeogenesis and other biosynthetic pathways. Notably, Hbt. salinarum does not utilize carbohydrates for energy, uncommon among Haloarchaea. We characterized a TrmB-family transcriptional regulator in a saccharolytic generalist, Haloarcula hispanica, to investigate whether the targets and function of TrmB, or its regulon, is conserved in related species with distinct metabolic capabilities. In Har. hispanica, TrmB binds to 15 sites in the genome and induces the expression of genes primarily involved in gluconeogenesis and tryptophan biosynthesis. An important regulatory control point in Hbt. salinarum, activation of ppsA and repression of pykA, is absent in Har. hispanica. Contrary to its role in Hbt. salinarum and saccharolytic hyperthermophiles, TrmB does not act as a global regulator: it does not directly repress the expression of glycolytic enzymes, peripheral pathways such as cofactor biosynthesis, or catabolism of other carbon sources in Har. hispanica. Cumulatively, these findings suggest rewiring of the TrmB regulon alongside metabolic network evolution in Haloarchaea.
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Affiliation(s)
- Rylee K. Hackley
- Department of Biology, Duke University, Durham, North Carolina, United States of America
- University Program in Genetics and Genomics, Duke University, Durham, North Carolina, United States of America
| | | | - Cynthia L. Darnell
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Amy K. Schmid
- Department of Biology, Duke University, Durham, North Carolina, United States of America
- University Program in Genetics and Genomics, Duke University, Durham, North Carolina, United States of America
- Center for Genomics and Computational Biology, Duke University, Durham, North Carolina, United States of America
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Flores-Villegas M, Rebnegger C, Kowarz V, Prielhofer R, Mattanovich D, Gasser B. Systematic sequence engineering enhances the induction strength of the glucose-regulated GTH1 promoter of Komagataella phaffii. Nucleic Acids Res 2023; 51:11358-11374. [PMID: 37791854 PMCID: PMC10639056 DOI: 10.1093/nar/gkad752] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 08/16/2023] [Accepted: 09/07/2023] [Indexed: 10/05/2023] Open
Abstract
The promoter of the high-affinity glucose transporter Gth1 (PGTH1) is tightly repressed on glucose and glycerol surplus, and strongly induced in glucose-limitation, thus enabling regulated methanol-free production processes in the yeast production host Komagataella phaffii. To further improve this promoter, an intertwined approach of nucleotide diversification through random and rational engineering was pursued. Random mutagenesis and fluorescence activated cell sorting of PGTH1 yielded five variants with enhanced induction strength. Reverse engineering of individual point mutations found in the improved variants identified two single point mutations with synergistic action. Sequential deletions revealed the key promoter segments for induction and repression properties, respectively. Combination of the single point mutations and the amplification of key promoter segments led to a library of novel promoter variants with up to 3-fold higher activity. Unexpectedly, the effect of gaining or losing a certain transcription factor binding site (TFBS) was highly dependent on its context within the promoter. Finally, the applicability of the novel promoter variants for biotechnological production was proven for the secretion of different recombinant model proteins in fed batch cultivation, where they clearly outperformed their ancestors. In addition to advancing the toolbox for recombinant protein production and metabolic engineering of K. phaffii, we discovered single nucleotide positions and correspondingly affected TFBS that distinguish between glycerol- and glucose-mediated repression of the native promoter.
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Affiliation(s)
- Mirelle Flores-Villegas
- CD-Laboratory for Growth-decoupled Protein Production in Yeast at Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
- University of Natural Resources and Life Sciences Vienna (BOKU), Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190 Vienna, Austria
| | - Corinna Rebnegger
- CD-Laboratory for Growth-decoupled Protein Production in Yeast at Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
- University of Natural Resources and Life Sciences Vienna (BOKU), Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190 Vienna, Austria
- ACIB GmbH, Muthgasse 11, 1190 Vienna, Austria
| | - Viktoria Kowarz
- CD-Laboratory for Growth-decoupled Protein Production in Yeast at Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
- University of Natural Resources and Life Sciences Vienna (BOKU), Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190 Vienna, Austria
| | - Roland Prielhofer
- University of Natural Resources and Life Sciences Vienna (BOKU), Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190 Vienna, Austria
| | - Diethard Mattanovich
- CD-Laboratory for Growth-decoupled Protein Production in Yeast at Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
- University of Natural Resources and Life Sciences Vienna (BOKU), Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190 Vienna, Austria
- ACIB GmbH, Muthgasse 11, 1190 Vienna, Austria
| | - Brigitte Gasser
- CD-Laboratory for Growth-decoupled Protein Production in Yeast at Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
- University of Natural Resources and Life Sciences Vienna (BOKU), Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190 Vienna, Austria
- ACIB GmbH, Muthgasse 11, 1190 Vienna, Austria
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Abstract
Saccharomyces cerevisiae, whose evolutionary past includes a whole-genome duplication event, is characterized by a mosaic genome configuration with substantial apparent genetic redundancy. This apparent redundancy raises questions about the evolutionary driving force for genomic fixation of “minor” paralogs and complicates modular and combinatorial metabolic engineering strategies. While isoenzymes might be important in specific environments, they could be dispensable in controlled laboratory or industrial contexts. The present study explores the extent to which the genetic complexity of the central carbon metabolism (CCM) in S. cerevisiae, here defined as the combination of glycolysis, the pentose phosphate pathway, the tricarboxylic acid cycle, and a limited number of related pathways and reactions, can be reduced by elimination of (iso)enzymes without major negative impacts on strain physiology. Cas9-mediated, groupwise deletion of 35 of the 111 genes yielded a “minimal CCM” strain which, despite the elimination of 32% of CCM-related proteins, showed only a minimal change in phenotype on glucose-containing synthetic medium in controlled bioreactor cultures relative to a congenic reference strain. Analysis under a wide range of other growth and stress conditions revealed remarkably few phenotypic changes from the reduction of genetic complexity. Still, a well-documented context-dependent role of GPD1 in osmotolerance was confirmed. The minimal CCM strain provides a model system for further research into genetic redundancy of yeast genes and a platform for strategies aimed at large-scale, combinatorial remodeling of yeast CCM.
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Two homologs of the Cat8 transcription factor are involved in the regulation of ethanol utilization in Komagataella phaffii. Curr Genet 2021; 67:641-661. [PMID: 33725138 PMCID: PMC8254726 DOI: 10.1007/s00294-021-01165-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 11/26/2022]
Abstract
The transcription factors Cat8 and Sip4 were described in Saccharomyces cerevisiae and Kluyveromyces lactis to have very similar DNA binding domains and to be necessary for derepression of a variety of genes under non-fermentative growth conditions via binding to the carbon source responsive elements (CSREs). The methylotrophic yeast Komagataella phaffii (syn Pichia pastoris) has two transcription factors (TFs), which are putative homologs of Cat8 based on sequence similarity, termed Cat8-1 and Cat8-2. It is yet unclear in which cellular processes they are involved and if one of them is actually the homolog of Sip4. To study the roles of the Cat8 homologs in K. phaffii, overexpression or deletion strains were generated for the two TFs. The ability of these mutant strains to grow on different carbon sources was tested, and transcript levels of selected genes from the carbon metabolism were quantified. Our experiments showed that the TFs are required for the growth of K. phaffii on C2 carbon sources, but not on glucose, glycerol or methanol. K. phaffii deleted for Cat8-1 showed impaired growth on acetate, while both Cat8-1 and Cat8-2 are involved in the growth of K. phaffii on ethanol. Correspondingly, both TFs are participating in the activation of ADH2, ALD4 and ACS1, three genes encoding enzymes important for the assimilation of ethanol. Different from S. cerevisiae and K. lactis, Cat8-1 is not regulating the transcription of the putative Sip4-family member Cat8-2 in K. phaffii. Furthermore, Cat8-1 is necessary for the activation of genes from the glyoxylate cycle, whereas Cat8-2 is necessary for the activation of genes from the carnitine shuttle. Neither Cat8-1 nor Cat8-2 are required for the activation of gluconeogenesis genes. Finally, the CAT8-2 gene is repressed by the Mig1-2 transcription factor on glucose and autorepressed by the Cat8-2 protein on all tested carbon sources. Our study identified the involvement of K. phaffii Cat8-1 and Cat8-2 in C2-metabolism, and highlighted similarities and differences to their homologs in other yeast species.
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Aponte-Ubillus JJ, Barajas D, Sterling H, Aghajanirefah A, Bardliving C, Peltier J, Shamlou P, Roy M, Gold D. Proteome profiling and vector yield optimization in a recombinant adeno-associated virus-producing yeast model. Microbiologyopen 2020; 9:e1136. [PMID: 33166081 PMCID: PMC7755776 DOI: 10.1002/mbo3.1136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 12/03/2022] Open
Abstract
Recent studies on recombinant adeno‐associated viral (rAAV) vector production demonstrated the generation of infectious viral particles in Saccharomyces cerevisiae. Proof‐of‐concept results showed low vector yields that correlated with low AAV DNA encapsidation rates. In an attempt to understand the host cell response to rAAV production, we profiled proteomic changes throughout the fermentation process by mass spectrometry. By comparing an rAAV‐producing yeast strain with a respective non‐producer control, we identified a subset of yeast host proteins with significantly different expression patterns during the rAAV induction period. Gene ontology enrichment and network interaction analyses identified changes in expression patterns associated mainly with protein folding, as well as amino acid metabolism, gluconeogenesis, and stress response. Specific fold change patterns of heat shock proteins and other stress protein markers suggested the occurrence of a cytosolic unfolded protein response during rAAV protein expression. Also, a correlative increase in proteins involved in response to oxidative stress suggested cellular activities to ameliorate the effects of reactive oxygen species or other oxidants. We tested the functional relevance of the identified host proteins by overexpressing selected protein leads using low‐ and high‐copy number plasmids. Increased vector yields up to threefold were observed in clones where proteins SSA1, SSE1, SSE2, CCP1, GTT1, and RVB2 were overexpressed. Recombinant expression of SSA1 and YDJ insect homologues (HSP40 and HSC70, respectively) in Sf9 cells led to a volumetric vector yield increase of 50% relative to control, which validated the importance of chaperone proteins in rAAV‐producing systems. Overall, these results highlight the utility of proteomic‐based tools for the understanding and optimization of rAAV‐producing recombinant strains.
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Affiliation(s)
- Juan Jose Aponte-Ubillus
- Process Sciences Department, Biomarin Pharmaceutical Inc., Novato, CA, USA.,Amgen Bioprocessing Center, Keck Graduate Institute, Claremont, CA, USA
| | - Daniel Barajas
- Process Sciences Department, Biomarin Pharmaceutical Inc., Novato, CA, USA
| | - Harry Sterling
- Process Sciences Department, Biomarin Pharmaceutical Inc., Novato, CA, USA
| | - Ali Aghajanirefah
- Process Sciences Department, Biomarin Pharmaceutical Inc., Novato, CA, USA
| | | | - Joseph Peltier
- Process Sciences Department, Biomarin Pharmaceutical Inc., Novato, CA, USA
| | - Parviz Shamlou
- Amgen Bioprocessing Center, Keck Graduate Institute, Claremont, CA, USA
| | - Mimi Roy
- Process Sciences Department, Biomarin Pharmaceutical Inc., Novato, CA, USA
| | - Daniel Gold
- Process Sciences Department, Biomarin Pharmaceutical Inc., Novato, CA, USA
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CgCmk1 Activates CgRds2 To Resist Low-pH Stress in Candida glabrata. Appl Environ Microbiol 2020; 86:AEM.00302-20. [PMID: 32245757 DOI: 10.1128/aem.00302-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/27/2020] [Indexed: 02/07/2023] Open
Abstract
In Candida glabrata, the transcription factor CgRds2 has been previously characterized as a regulator of glycerophospholipid metabolism, playing a crucial role in the response to osmotic stress. Here, we report that CgRds2 is also involved in the response to pH 2.0 stress. At pH 2.0, the deletion of CgRDS2 led to reduced cell growth and survival, by 33% and 57%, respectively, compared with those of the wild-type strain. These adverse phenotypes resulted from the downregulation of genes related to energy metabolism in the Cgrds2Δ strain at pH 2.0, which led to a 34% reduction of the intracellular ATP content and a 24% decrease in membrane permeability. In contrast, the overexpression of CgRDS2 rescued the growth defect of the Cgrds2Δ strain and increased cell survival at pH 2.0 by 17% compared with that of the wild-type strain, and this effect was accompanied by significant increases in ATP content and membrane permeability, by 42% and 19%, respectively. Furthermore, we found that the calcium/calmodulin-dependent protein kinase (CaMK) CgCmk1 physically interacts with the PAS domain of CgRds2, and CgCmk1 is required for CgRds2 activation and translocation from the cytoplasm to the nucleus under pH 2.0 stress. Moreover, CgCmk1 is critical for CgRds2 function in resistance to pH 2.0 stress, because cells of the Cgrds2-pas strain with a disrupted CgCmk1-CgRds2 interaction exhibited impaired energy metabolism and membrane permeability at pH 2.0. Therefore, our results indicate that CgCmk1 positively regulates CgRds2 and suggest that they promote resistance to low-pH stress by enhancing energy metabolism and membrane permeability in C. glabrata IMPORTANCE An acidic environment is the main problem in the production of organic acids in C. glabrata The present study reports that the calcium/calmodulin-dependent protein kinase CgCmk1 positively regulates CgRds2 to increase intracellular ATP content, membrane permeability, and resistance to low-pH stress. Hence, the transcription factor CgRds2 may be a potential target for improving the acid stress tolerance of C. glabrata during the fermentation of organic acids. The present study also establishes a new link between the calcium signaling pathway and energy metabolism.
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Ravikrishnan A, Blank LM, Srivastava S, Raman K. Investigating metabolic interactions in a microbial co-culture through integrated modelling and experiments. Comput Struct Biotechnol J 2020; 18:1249-1258. [PMID: 32551031 PMCID: PMC7286961 DOI: 10.1016/j.csbj.2020.03.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/10/2020] [Accepted: 03/20/2020] [Indexed: 01/13/2023] Open
Abstract
Microbial co-cultures have been used in several biotechnological applications. Within these co-cultures, the microorganisms tend to interact with each other and perform complex actions. Investigating metabolic interactions in microbial co-cultures is crucial in designing microbial consortia. Here, we present a pipeline integrating modelling and experimental approaches to understand metabolic interactions between organisms in a community. We define a new index named "Metabolic Support Index (MSI)", which quantifies the benefits derived by each organism in the presence of the other when grown as a co-culture. We computed MSI for several experimentally demonstrated co-cultures and showed that MSI, as a metric, accurately identifies the organism that derives the maximum benefit. We also computed MSI for a commonly used yeast co-culture consisting of Saccharomyces cerevisiae and Pichia stipitis and observed that the latter derives higher benefit from the interaction. Further, we designed two-stage experiments to study mutual interactions and showed that P. stipitis indeed derives the maximum benefit from the interaction, as shown from our computational predictions. Also, using our previously developed computational tool MetQuest, we identified all the metabolic exchanges happening between these organisms by analysing the pathways spanning the two organisms. By analysing the HPLC profiles and studying the isotope labelling, we show that P. stipitis consumes the ethanol produced by S. cerevisiae when grown on glucose-rich medium under aerobic conditions, as also indicated by our in silico pathway analyses. Our approach represents an important step in understanding metabolic interactions in microbial communities through an integrated computational and experimental workflow.
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Affiliation(s)
- Aarthi Ravikrishnan
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology (IIT) Madras, Chennai 600 036, India
- Initiative for Biological Systems Engineering, IIT Madras, India
- Robert Bosch Centre for Data Science and Artificial Intelligence, IIT Madras, India
- Institute of Applied Microbiology - iAMB, Aachen Biology and Biotechnology – ABBt, Worringer Weg 1, RWTH Aachen University, D-52074 Aachen, Germany
| | - Lars M. Blank
- Institute of Applied Microbiology - iAMB, Aachen Biology and Biotechnology – ABBt, Worringer Weg 1, RWTH Aachen University, D-52074 Aachen, Germany
| | - Smita Srivastava
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology (IIT) Madras, Chennai 600 036, India
| | - Karthik Raman
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology (IIT) Madras, Chennai 600 036, India
- Initiative for Biological Systems Engineering, IIT Madras, India
- Robert Bosch Centre for Data Science and Artificial Intelligence, IIT Madras, India
- Corresponding author.
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Vengayil V, Rashida Z, Laxman S. The E3 ubiquitin ligase Pib1 regulates effective gluconeogenic shutdown upon glucose availability. J Biol Chem 2019; 294:17209-17223. [PMID: 31604822 PMCID: PMC6873170 DOI: 10.1074/jbc.ra119.009822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/27/2019] [Indexed: 12/31/2022] Open
Abstract
Cells use multiple mechanisms to regulate their metabolic states in response to changes in their nutrient environment. One example is the response of cells to glucose. In Saccharomyces cerevisiae growing in glucose-depleted medium, the re-availability of glucose leads to the down-regulation of gluconeogenesis and the activation of glycolysis, leading to "glucose repression." However, our knowledge of the mechanisms mediating the glucose-dependent down-regulation of the gluconeogenic transcription factors is limited. Using the major gluconeogenic transcription factor Rds2 as a candidate, we identify here a novel role for the E3 ubiquitin ligase Pib1 in regulating the stability and degradation of Rds2. Glucose addition to cells growing under glucose limitation results in a rapid ubiquitination of Rds2, followed by its proteasomal degradation. Through in vivo and in vitro experiments, we establish Pib1 as the ubiquitin E3 ligase that regulates Rds2 ubiquitination and stability. Notably, this Pib1-mediated Rds2 ubiquitination, followed by proteasomal degradation, is specific to the presence of glucose. This Pib1-mediated ubiquitination of Rds2 depends on the phosphorylation state of Rds2, suggesting a cross-talk between ubiquitination and phosphorylation to achieve a metabolic state change. Using stable isotope-based metabolic flux experiments, we find that the loss of Pib1 results in an imbalanced gluconeogenic state, regardless of glucose availability. Pib1 is required for complete glucose repression and enables cells to optimally grow in competitive environments when glucose again becomes available. Our results reveal the existence of a Pib1-mediated regulatory program that mediates glucose repression when glucose availability is restored.
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Affiliation(s)
- Vineeth Vengayil
- Institute for Stem Cell Science and Regenerative Medicine (inStem), GKVK Post, Bellary Road, Bangalore 560065, India
- Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Zeenat Rashida
- Institute for Stem Cell Science and Regenerative Medicine (inStem), GKVK Post, Bellary Road, Bangalore 560065, India
- Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Sunil Laxman
- Institute for Stem Cell Science and Regenerative Medicine (inStem), GKVK Post, Bellary Road, Bangalore 560065, India
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12
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Ruchala J, Kurylenko OO, Dmytruk KV, Sibirny AA. Construction of advanced producers of first- and second-generation ethanol in Saccharomyces cerevisiae and selected species of non-conventional yeasts (Scheffersomyces stipitis, Ogataea polymorpha). J Ind Microbiol Biotechnol 2019; 47:109-132. [PMID: 31637550 PMCID: PMC6970964 DOI: 10.1007/s10295-019-02242-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/01/2019] [Indexed: 12/20/2022]
Abstract
This review summarizes progress in the construction of efficient yeast ethanol producers from glucose/sucrose and lignocellulose. Saccharomyces cerevisiae is the major industrial producer of first-generation ethanol. The different approaches to increase ethanol yield and productivity from glucose in S. cerevisiae are described. Construction of the producers of second-generation ethanol is described for S. cerevisiae, one of the best natural xylose fermenters, Scheffersomyces stipitis and the most thermotolerant yeast known Ogataea polymorpha. Each of these organisms has some advantages and drawbacks. S. cerevisiae is the primary industrial ethanol producer and is the most ethanol tolerant natural yeast known and, however, cannot metabolize xylose. S. stipitis can effectively ferment both glucose and xylose and, however, has low ethanol tolerance and requires oxygen for growth. O. polymorpha grows and ferments at high temperatures and, however, produces very low amounts of ethanol from xylose. Review describes how the mentioned drawbacks could be overcome.
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Affiliation(s)
- Justyna Ruchala
- Department of Microbiology and Biotechnology, University of Rzeszow, Zelwerowicza 4, 35-601, Rzeszow, Poland
| | - Olena O Kurylenko
- Department of Molecular Genetics and Biotechnology, Institute of Cell Biology, NAS of Ukraine, Drahomanov Street, 14/16, Lviv, 79005, Ukraine
| | - Kostyantyn V Dmytruk
- Department of Molecular Genetics and Biotechnology, Institute of Cell Biology, NAS of Ukraine, Drahomanov Street, 14/16, Lviv, 79005, Ukraine
| | - Andriy A Sibirny
- Department of Microbiology and Biotechnology, University of Rzeszow, Zelwerowicza 4, 35-601, Rzeszow, Poland.
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13
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Chew SY, Chee WJY, Than LTL. The glyoxylate cycle and alternative carbon metabolism as metabolic adaptation strategies of Candida glabrata: perspectives from Candida albicans and Saccharomyces cerevisiae. J Biomed Sci 2019; 26:52. [PMID: 31301737 PMCID: PMC6626413 DOI: 10.1186/s12929-019-0546-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/09/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Carbon utilization and metabolism are fundamental to every living organism for cellular growth. For intracellular human fungal pathogens such as Candida glabrata, an effective metabolic adaptation strategy is often required for survival and pathogenesis. As one of the host defence strategies to combat invading pathogens, phagocytes such as macrophages constantly impose restrictions on pathogens' access to their preferred carbon source, glucose. Surprisingly, it has been reported that engulfed C. glabrata are able to survive in this harsh microenvironment, further suggesting alternative carbon metabolism as a potential strategy for this opportunistic fungal pathogen to persist in the host. MAIN TEXT In this review, we discuss alternative carbon metabolism as a metabolic adaptation strategy for the pathogenesis of C. glabrata. As the glyoxylate cycle is an important pathway in the utilization of alternative carbon sources, we also highlight the key metabolic enzymes in the glyoxylate cycle and its necessity for the pathogenesis of C. glabrata. Finally, we explore the transcriptional regulatory network of the glyoxylate cycle. CONCLUSION Considering evidence from Candida albicans and Saccharomyces cerevisiae, this review summarizes the current knowledge of the glyoxylate cycle as an alternative carbon metabolic pathway of C. glabrata.
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Affiliation(s)
- Shu Yih Chew
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Wallace Jeng Yang Chee
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Leslie Thian Lung Than
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
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14
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Rajkumar AS, Özdemir E, Lis AV, Schneider K, Qin J, Jensen MK, Keasling JD. Engineered Reversal of Function in Glycolytic Yeast Promoters. ACS Synth Biol 2019; 8:1462-1468. [PMID: 31051075 DOI: 10.1021/acssynbio.9b00027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Promoters are key components of cell factory design, allowing precise expression of genes in a heterologous pathway. Several commonly used promoters in yeast cell factories belong to glycolytic genes, highly expressed in actively growing yeast when glucose is used as a carbon source. However, their expression can be suboptimal when alternate carbon sources are used, or if there is a need to decouple growth from production. Hence, there is a need for alternate promoters for different carbon sources and production schemes. In this work, we demonstrate a reversal of regulatory function in two glycolytic yeast promoters by replacing glycolytic regulatory elements with ones induced by the diauxic shift. We observe a shift in induction from glucose-rich to glucose-poor medium without loss of regulatory activity, and strong ethanol induction. Applications of these promoters were validated for expression of the vanillin biosynthetic pathway, reaching production of vanillin comparable to pathway designs using strong constitutive promoters.
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Affiliation(s)
- Arun S. Rajkumar
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Emre Özdemir
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Alicia V. Lis
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Konstantin Schneider
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Jiufu Qin
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Michael K. Jensen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Jay D. Keasling
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
- Joint BioEnergy Institute, Emeryville, California 94608, United States
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94704, United States
- Department of Chemical and Biomolecular Engineering & Department of Bioengineering, University of California, Berkeley, California 94720-1462, United States
- Center for Synthetic Biochemistry, Institute for Synthetic Biology, Shenzhen Institutes of Advanced Technologies, Shenzhen, China
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15
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Xiberras J, Klein M, Nevoigt E. Glycerol as a substrate for Saccharomyces cerevisiae based bioprocesses - Knowledge gaps regarding the central carbon catabolism of this 'non-fermentable' carbon source. Biotechnol Adv 2019; 37:107378. [PMID: 30930107 DOI: 10.1016/j.biotechadv.2019.03.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/22/2019] [Accepted: 03/26/2019] [Indexed: 12/14/2022]
Abstract
Glycerol is an interesting alternative carbon source in industrial bioprocesses due to its higher degree of reduction per carbon atom compared to sugars. During the last few years, significant progress has been made in improving the well-known industrial platform organism Saccharomyces cerevisiae with regard to its glycerol utilization capability, particularly in synthetic medium. This provided a basis for future metabolic engineering focusing on the production of valuable chemicals from glycerol. However, profound knowledge about the central carbon catabolism in synthetic glycerol medium is a prerequisite for such incentives. As a matter of fact, the current assumptions about the actual in vivo fluxes active on glycerol as the sole carbon source have mainly been based on omics data collected in complex media or were even deduced from studies with other non-fermentable carbon sources, such as ethanol or acetate. A number of uncertainties have been identified which particularly regard the role of the glyoxylate cycle, the subcellular localization of the respective enzymes, the contributions of mitochondrial transporters and the active anaplerotic reactions under these conditions. The review scrutinizes the current knowledge, highlights the necessity to collect novel experimental data using cells growing in synthetic glycerol medium and summarizes the current state of the art with regard to the production of valuable fermentation products from a carbon source that has been considered so far as 'non-fermentable' for the yeast S. cerevisiae.
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Affiliation(s)
- Joeline Xiberras
- Department of Life Sciences and Chemistry, Jacobs University gGmbH, Campus Ring 1, 28759 Bremen, Germany
| | - Mathias Klein
- Department of Life Sciences and Chemistry, Jacobs University gGmbH, Campus Ring 1, 28759 Bremen, Germany
| | - Elke Nevoigt
- Department of Life Sciences and Chemistry, Jacobs University gGmbH, Campus Ring 1, 28759 Bremen, Germany.
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16
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CgHog1-Mediated CgRds2 Phosphorylation Alters Glycerophospholipid Composition To Coordinate Osmotic Stress in Candida glabrata. Appl Environ Microbiol 2019; 85:AEM.02822-18. [PMID: 30635387 DOI: 10.1128/aem.02822-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 01/04/2019] [Indexed: 12/11/2022] Open
Abstract
Under stress conditions, Hog1 is required for cell survival through transiently phosphorylating downstream targets and reprogramming gene expression. Here, we report that Candida glabrata Hog1 (CgHog1) interacts with and phosphorylates CgRds2, a zinc cluster transcription factor, in response to osmotic stress. Additionally, we found that deletion of CgRDS2 led to decreases in cell growth and cell survival by 23.4% and 39.6%, respectively, at 1.5 M NaCl, compared with levels of the wild-type strain. This is attributed to significant downregulation of the expression levels of glycerophospholipid metabolism genes. As a result, the content of total glycerophospholipid decreased by 30.3%. Membrane integrity also decreased 47.6% in the Cgrds2Δ strain at 1.5 M NaCl. In contrast, overexpression of CgRDS2 increased the cell growth and cell survival by 10.2% and 6.3%, respectively, owing to a significant increase in the total glycerophospholipid content and increased membrane integrity by 27.2% and 12.1%, respectively, at 1.5 M NaCl, compared with levels for the wild-type strain. However, a strain in which the CgRDS2 gene encodes the replacement of Ser64 and Thr97 residues with alanines (Cgrds22A ), harboring a CgRds2 protein that was not phosphorylated by CgHog1, failed to promote glycerophospholipid metabolism and membrane integrity at 1.5 M NaCl. Thus, the above results demonstrate that CgHog1-mediated CgRds2 phosphorylation enhanced glycerophospholipid composition and membrane integrity to resist osmotic stress in C. glabrata IMPORTANCE This study explored the role of CgHog1-mediated CgRds2 phosphorylation in response to osmotic stress in Candida glabrata CgHog1 interacts with and phosphorylates CgRds2, a zinc cluster transcription factor, under osmotic stress. Phosphorylated CgRds2 plays an important role in increasing glycerophospholipid composition and membrane integrity, thereby enhancing cell growth and survival.
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17
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Stasyk OG, Denega IO, Padhorny D, Dmytruk KV, Kozakov D, Abbas C, Stasyk OV. Glucose regulation in the methylotrophic yeast Hansenula (Ogataea) polymorpha is mediated by a putative transceptor Gcr1. Int J Biochem Cell Biol 2018; 103:25-34. [PMID: 30081098 DOI: 10.1016/j.biocel.2018.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 07/31/2018] [Accepted: 08/02/2018] [Indexed: 12/26/2022]
Abstract
The HpGcr1, a hexose transporter homologue from the methylotrophic yeast Hansenula (Ogataea) polymorpha, was previously identified as being involved in glucose repression. Intriguingly, potential HpGcr1 orthologues are found only in the genomes of a few yeasts phylogenetically closely related to H. polymorpha, but are absent in all other yeasts. The other closest HpGcr1 homologues are fungal high-affinity glucose symporters or putative transceptors suggesting a possible HpGcr1 origin due to a specific archaic gene retention or via horizontal gene transfer from Eurotiales fungi. Herein we report that, similarly to other yeast non-transporting glucose sensors, the substitution of the conserved arginine residue converts HpGcr1R165K into a constitutively signaling form. Synthesis of HpGcr1R165K in gcr1Δ did not restore glucose transport or repression but instead profoundly impaired growth independent of carbon source used. Simultaneously, gcr1Δ was impaired in transcriptional induction of repressible peroxisomal alcohol oxidase and in growth on methanol. Overexpression of the functional transporter HpHxt1 in gcr1Δ partially restored growth on glucose and glucose repression but did not rescue impaired growth on methanol. Heterologous expression of HpGcr1 in a Saccharomyces cerevisiae hxt-null strain did not restore glucose uptake due to protein mislocalization. However, HpGcr1 overexpression in H. polymorpha led to increased sensitivity to extracellular 2-deoxyglucose, suggesting HpGcr1 is a functional glucose carrier. The combined data suggest that HpGcr1 represents a novel type of yeast glucose transceptor functioning also in the absence of glucose.
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Affiliation(s)
- Olena G Stasyk
- Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine; Department of Biochemistry, Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Iryna O Denega
- Department of Biochemistry, Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Dzmitry Padhorny
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Kostyantyn V Dmytruk
- Department of Molecular Genetics and Biotechnology, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
| | - Dima Kozakov
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York, USA
| | | | - Oleh V Stasyk
- Department of Cell Signaling, Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine.
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18
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Metabolic Adaptation to Nutrients Involves Coregulation of Gene Expression by the RNA Helicase Dbp2 and the Cyc8 Corepressor in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2017; 7:2235-2247. [PMID: 28500049 PMCID: PMC5499131 DOI: 10.1534/g3.117.041814] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cells fine-tune their metabolic programs according to nutrient availability in order to maintain homeostasis. This is achieved largely through integrating signaling pathways and the gene expression program, allowing cells to adapt to nutritional change. Dbp2, a member of the DEAD-box RNA helicase family in Saccharomyces cerevisiae, has been proposed to integrate gene expression with cellular metabolism. Prior work from our laboratory has reported the necessity of DBP2 in proper gene expression, particularly for genes involved in glucose-dependent regulation. Here, by comparing differentially expressed genes in dbp2∆ to those of 700 other deletion strains from other studies, we find that CYC8 and TUP1, which form a complex and inhibit transcription of numerous genes, corepress a common set of genes with DBP2. Gene ontology (GO) annotations reveal that these corepressed genes are related to cellular metabolism, including respiration, gluconeogenesis, and alternative carbon-source utilization genes. Consistent with a direct role in metabolic gene regulation, loss of either DBP2 or CYC8 results in increased cellular respiration rates. Furthermore, we find that corepressed genes have a propensity to be associated with overlapping long noncoding RNAs and that upregulation of these genes in the absence of DBP2 correlates with decreased binding of Cyc8 to these gene promoters. Taken together, this suggests that Dbp2 integrates nutrient availability with energy homeostasis by maintaining repression of glucose-repressed, Cyc8-targeted genes across the genome.
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19
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Bolotin-Fukuhara M. Thirty years of the HAP2/3/4/5 complex. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:543-559. [DOI: 10.1016/j.bbagrm.2016.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 01/22/2023]
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Reprogramming of nonfermentative metabolism by stress-responsive transcription factors in the yeast Saccharomyces cerevisiae. Curr Genet 2016; 63:1-7. [PMID: 27180089 DOI: 10.1007/s00294-016-0609-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 05/05/2016] [Accepted: 05/07/2016] [Indexed: 12/15/2022]
Abstract
The fundamental questions of how cells control growth and respond to stresses have captivated scientists for years. Despite the complexity of these cellular processes, we could approach this puzzle by asking our favorite model yeast, Saccharomyces cerevisiae, how it makes a critical decision to either proliferate, to rest in a quiescent state or to program itself to die. This review highlights the essentiality of transcriptional factors in the reprogramming of gene expression as a prime mechanism of cellular stress responses. A whelm of evidence shows that transcriptional factors allow cells to acquire appropriate and unified responses to the transmitted signals. They function to modulate pathway-specific gene expression and organize transcriptomic responses to the altered environments. This review is aimed to summarize current knowledge on the roles of novel and well-known yeast transcription factors in the control of growth and stress responses during glucose deprivation as a prototypical case study. The scope includes stress sensing, transcription factors' identity, gene regulation and proposed crosstalks between pathways, associated with stress responses. A complex commander system of multiple stress-responsive transcription factors, observed here and elsewhere, indicates that regulation of glucose starvation/diauxic shift is a highly sophisticated and well-controlled process, involving elaborative networks of different kinase/target proteins. Using S. cerevisiae as a model, basic genetic research studies on gene identification have once again proved to be essential in the comprehension of molecular basis of cellular stress responses. Insights into this fundamental and highly conserved phenomenon will endow important prospective impacts on biotechnological applications and healthcare improvement.
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21
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Deroover S, Ghillebert R, Broeckx T, Winderickx J, Rolland F. Trehalose-6-phosphate synthesis controls yeast gluconeogenesis downstream and independent of SNF1. FEMS Yeast Res 2016; 16:fow036. [PMID: 27189362 DOI: 10.1093/femsyr/fow036] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2016] [Indexed: 11/12/2022] Open
Abstract
Trehalose-6-P (T6P), an intermediate of trehalose biosynthesis, was identified as an important regulator of yeast sugar metabolism and signaling. tps1Δ mutants, deficient in T6P synthesis (TPS), are unable to grow on rapidly fermentable medium with uncontrolled influx in glycolysis, depletion of ATP and accumulation of sugar phosphates. However, the exact molecular mechanisms involved are not fully understood. We show that SNF1 deletion restores the tps1Δ growth defect on glucose, suggesting that lack of TPS hampers inactivation of SNF1 or SNF1-regulated processes. In addition to alternative, non-fermentable carbon metabolism, SNF1 controls two major processes: respiration and gluconeogenesis. The tps1Δ defect appears to be specifically associated with deficient inhibition of gluconeogenesis, indicating more downstream effects. Consistently, Snf1 dephosphorylation and inactivation on glucose medium are not affected, as confirmed with an in vivo Snf1 activity reporter. Detailed analysis shows that gluconeogenic Pck1 and Fbp1 expression, protein levels and activity are not repressed upon glucose addition to tps1Δ cells, suggesting a link between the metabolic defect and persistent gluconeogenesis. While SNF1 is essential for induction of gluconeogenesis, T6P/TPS is required for inactivation of gluconeogenesis in the presence of glucose, downstream and independent of SNF1 activity and the Cat8 and Sip4 transcription factors.
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Affiliation(s)
- Sofie Deroover
- Laboratory of Molecular Plant Biology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium
| | - Ruben Ghillebert
- Laboratory of Functional Biology, Department of Biology, KU Leuven, B-3001 Leuven, Belgium
| | - Tom Broeckx
- Laboratory of Molecular Plant Biology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium
| | - Joris Winderickx
- Laboratory of Functional Biology, Department of Biology, KU Leuven, B-3001 Leuven, Belgium
| | - Filip Rolland
- Laboratory of Molecular Plant Biology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium
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22
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Jansuriyakul S, Somboon P, Rodboon N, Kurylenko O, Sibirny A, Soontorngun N. The zinc cluster transcriptional regulator Asg1 transcriptionally coordinates oleate utilization and lipid accumulation in Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2016; 100:4549-60. [PMID: 26875874 DOI: 10.1007/s00253-016-7356-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 01/18/2016] [Accepted: 01/23/2016] [Indexed: 01/22/2023]
Abstract
In this study, we characterize a new function for activator of stress response genes (Asg1) in fatty acid utilization. Asg1 is required for full activation of genes in several pathways, including β-oxidation (POX1, FOX2, and POT1), gluconeogenesis (PCK1), glyoxylate cycle (ICL1), triacylglycerol breakdown (TGL3), and peroxisomal transport (PXA1). In addition, the transcriptional activator Asg1 is found to be enriched on promoters of genes in β-oxidation and gluconeogenesis pathways, suggesting that Asg1 is directly involved in the control of fatty acid utilizing genes. In agreement, impaired growth on non-fermentable carbons such as fatty acids and oils and increased sensitivity to some oxidative agents are found for the Δasg1 strain. The lipid class profile of the Δasg1 cells grown in oleate displays approximately 3-fold increase in free fatty acid (FFA) content in comparison to glucose-grown cells, which correlates with decreased expression of β-oxidation genes. The ∆asg1 strain grown in glucose also exhibits higher accumulation of triacylglycerols (TAGs) during log phase, reaching levels typically observed in stationary phase cells. Altered TAG accumulation is partly due to the inability of the Δasg1 cells to efficiently break down TAGs, which is consistent with lowered expression of TGL3 gene, encoding triglycerol lipase. Overall, these results highlight a new role of the transcriptional regulator Asg1 in coordinating expression of genes involved in fatty acid utilization and its role in regulating cellular lipid accumulation, thereby providing an attractive approach to increase FFAs and TAGs content for the production of lipid-derived biofuels and chemicals in Saccharomyces cerevisiae.
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Affiliation(s)
- Siripat Jansuriyakul
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, 49 Tianthalay Road, Tha Kham, Bangkhuntian, Bangkok, 10150, Thailand
| | - Pichayada Somboon
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, 49 Tianthalay Road, Tha Kham, Bangkhuntian, Bangkok, 10150, Thailand
| | - Napachai Rodboon
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, 49 Tianthalay Road, Tha Kham, Bangkhuntian, Bangkok, 10150, Thailand
| | - Olena Kurylenko
- NAS of Ukraine, Institute of Cell Biology, Drahomanov Street, 14/16, Lviv, 79005, Ukraine
| | - Andriy Sibirny
- NAS of Ukraine, Institute of Cell Biology, Drahomanov Street, 14/16, Lviv, 79005, Ukraine.,Department of Bioetchnology and Microbiology, University of Rzeszow, Zelwerowicza Street, 4, 35-601, Rzeszow, Poland
| | - Nitnipa Soontorngun
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, 49 Tianthalay Road, Tha Kham, Bangkhuntian, Bangkok, 10150, Thailand.
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Bergen AC, Olsen GM, Fay JC. Divergent MLS1 Promoters Lie on a Fitness Plateau for Gene Expression. Mol Biol Evol 2016; 33:1270-9. [PMID: 26782997 PMCID: PMC4839218 DOI: 10.1093/molbev/msw010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Qualitative patterns of gene activation and repression are often conserved despite an abundance of quantitative variation in expression levels within and between species. A major challenge to interpreting patterns of expression divergence is knowing which changes in gene expression affect fitness. To characterize the fitness effects of gene expression divergence, we placed orthologous promoters from eight yeast species upstream of malate synthase (MLS1) in Saccharomyces cerevisiae. As expected, we found these promoters varied in their expression level under activated and repressed conditions as well as in their dynamic response following loss of glucose repression. Despite these differences, only a single promoter driving near basal levels of expression caused a detectable loss of fitness. We conclude that the MLS1 promoter lies on a fitness plateau whereby even large changes in gene expression can be tolerated without a substantial loss of fitness.
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Affiliation(s)
- Andrew C Bergen
- Molecular Genetics and Genomics Program, Washington University, St. Louis
| | | | - Justin C Fay
- Department of Genetics, Washington University, St. Louis Center for Genome Sciences and Systems Biology, Washington University, St. Louis
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Sanz P, Viana R, Garcia-Gimeno MA. AMPK in Yeast: The SNF1 (Sucrose Non-fermenting 1) Protein Kinase Complex. EXPERIENTIA SUPPLEMENTUM (2012) 2016; 107:353-374. [PMID: 27812987 DOI: 10.1007/978-3-319-43589-3_14] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In yeast, SNF1 protein kinase is the orthologue of mammalian AMPK complex. It is a trimeric complex composed of Snf1 protein kinase (orthologue of AMPKα catalytic subunit), Snf4 (orthologue of AMPKγ regulatory subunit), and a member of the Gal83/Sip1/Sip2 family of proteins (orthologues of AMPKβ subunit) that act as scaffolds and also regulate the subcellular localization of the complex. In this chapter, we review the recent literature on the characteristics of SNF1 complex subunits, the structure and regulation of the activity of the SNF1 complex, its role at the level of transcriptional regulation of relevant target genes and also at the level of posttranslational modification of targeted substrates. We also review the crosstalk of SNF1 complex activity with other key protein kinase pathways such as cAMP-PKA, TORC1, and PAS kinase.
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Affiliation(s)
- Pascual Sanz
- Instituto de Biomedicina de Valencia, CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCiii), Jaime Roig 11, 46010, Valencia, Spain.
| | - Rosa Viana
- Instituto de Biomedicina de Valencia, CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCiii), Jaime Roig 11, 46010, Valencia, Spain
| | - Maria Adelaida Garcia-Gimeno
- Department of Biotecnología, Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural (ETSIAMN), Universitat Politécnica de Valencia, Valencia, Spain
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Casal M, Queirós O, Talaia G, Ribas D, Paiva S. Carboxylic Acids Plasma Membrane Transporters in Saccharomyces cerevisiae. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 892:229-251. [PMID: 26721276 DOI: 10.1007/978-3-319-25304-6_9] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
This chapter covers the functionally characterized plasma membrane carboxylic acids transporters Jen1, Ady2, Fps1 and Pdr12 in the yeast Saccharomyces cerevisiae, addressing also their homologues in other microorganisms, as filamentous fungi and bacteria. Carboxylic acids can either be transported into the cells, to be used as nutrients, or extruded in response to acid stress conditions. The secondary active transporters Jen1 and Ady2 can mediate the uptake of the anionic form of these substrates by a H(+)-symport mechanism. The undissociated form of carboxylic acids is lipid-soluble, crossing the plasma membrane by simple diffusion. Furthermore, acetic acid can also be transported by facilitated diffusion via Fps1 channel. At the cytoplasmic physiological pH, the anionic form of the acid prevails and it can be exported by the Pdr12 pump. This review will highlight the mechanisms involving carboxylic acids transporters, and the way they operate according to the yeast cell response to environmental changes, as carbon source availability, extracellular pH and acid stress conditions.
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Affiliation(s)
- Margarida Casal
- CBMA-Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
| | - Odília Queirós
- CBMA-Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- CESPU, Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Rua Central de Gandra, 1317, 4585-116, Gandra, PRD, Portugal
| | - Gabriel Talaia
- CBMA-Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - David Ribas
- CBMA-Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Sandra Paiva
- CBMA-Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
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Tangsombatvichit P, Semkiv MV, Sibirny AA, Jensen LT, Ratanakhanokchai K, Soontorngun N. Zinc cluster protein Znf1, a novel transcription factor of non-fermentative metabolism in Saccharomyces cerevisiae. FEMS Yeast Res 2015; 15:fou002. [PMID: 25673751 DOI: 10.1093/femsyr/fou002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The ability to rapidly respond to nutrient changes is a fundamental requirement for cell survival. Here, we show that the zinc cluster regulator Znf1 responds to altered nutrient signals following glucose starvation through the direct control of genes involved in non-fermentative metabolism, including those belonged to the central pathways of gluconeogenesis (PCK1, FBP1 and MDH2), glyoxylate shunt (MLS1 and ICL1) and the tricarboxylic acid cycle (ACO1), which is demonstrated by Znf1-binding enrichment at these promoters during the glucose-ethanol shift. Additionally, reduced Pck1 and Fbp1 enzymatic activities correlate well with the data obtained from gene transcription analysis. Cells deleted for ZNF1 also display defective mitochondrial morphology with unclear structures of the inner membrane cristae when grown in ethanol, in agreement with the substantial reduction in the ATP content, suggesting for roles of Znf1 in maintaining mitochondrial morphology and function. Furthermore, Znf1 also plays a role in tolerance to pH and osmotic stress, especially during the oxidative metabolism. Taken together, our results clearly suggest that Znf1 is a critical transcriptional regulator for stress adaptation during non-fermentative growth with some partial overlapping targets with previously reported regulators in Saccharomyces cerevisiae.
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Affiliation(s)
- Pitchya Tangsombatvichit
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok 10150, Thailand
| | - Marta V Semkiv
- Institute of Cell Biology, NAS of Ukraine, Lviv 79005, Ukraine
| | - Andriy A Sibirny
- Institute of Cell Biology, NAS of Ukraine, Lviv 79005, Ukraine Department of Biotechnology and Microbiology, University of Rzeszow, Rzeszow 35-601, Poland
| | - Laran T Jensen
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Khanok Ratanakhanokchai
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok 10150, Thailand
| | - Nitnipa Soontorngun
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok 10150, Thailand
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Lubitz T, Welkenhuysen N, Shashkova S, Bendrioua L, Hohmann S, Klipp E, Krantz M. Network reconstruction and validation of the Snf1/AMPK pathway in baker's yeast based on a comprehensive literature review. NPJ Syst Biol Appl 2015; 1:15007. [PMID: 28725459 PMCID: PMC5516868 DOI: 10.1038/npjsba.2015.7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 06/19/2015] [Accepted: 07/14/2015] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND/OBJECTIVES The SNF1/AMPK protein kinase has a central role in energy homeostasis in eukaryotic cells. It is activated by energy depletion and stimulates processes leading to the production of ATP while it downregulates ATP-consuming processes. The yeast SNF1 complex is best known for its role in glucose derepression. METHODS We performed a network reconstruction of the Snf1 pathway based on a comprehensive literature review. The network was formalised in the rxncon language, and we used the rxncon toolbox for model validation and gap filling. RESULTS We present a machine-readable network definition that summarises the mechanistic knowledge of the Snf1 pathway. Furthermore, we used the known input/output relationships in the network to identify and fill gaps in the information transfer through the pathway, to produce a functional network model. Finally, we convert the functional network model into a rule-based model as a proof-of-principle. CONCLUSIONS The workflow presented here enables large scale reconstruction, validation and gap filling of signal transduction networks. It is analogous to but distinct from that established for metabolic networks. We demonstrate the workflow capabilities, and the direct link between the reconstruction and dynamic modelling, with the Snf1 network. This network is a distillation of the knowledge from all previous publications on the Snf1/AMPK pathway. The network is a knowledge resource for modellers and experimentalists alike, and a template for similar efforts in higher eukaryotes. Finally, we envisage the workflow as an instrumental tool for reconstruction of large signalling networks across Eukaryota.
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Affiliation(s)
- Timo Lubitz
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Niek Welkenhuysen
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Sviatlana Shashkova
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Loubna Bendrioua
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Stefan Hohmann
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Edda Klipp
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Marcus Krantz
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
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Tsang F, Lin SJ. Less is more: Nutrient limitation induces cross-talk of nutrient sensing pathways with NAD + homeostasis and contributes to longevity. ACTA ACUST UNITED AC 2015; 10:333-357. [PMID: 27683589 DOI: 10.1007/s11515-015-1367-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nutrient sensing pathways and their regulation grant cells control over their metabolism and growth in response to changing nutrients. Factors that regulate nutrient sensing can also modulate longevity. Reduced activity of nutrient sensing pathways such as glucose-sensing PKA, nitrogen-sensing TOR and S6 kinase homolog Sch9 have been linked to increased life span in the yeast, Saccharomyces cerevisiae, and higher eukaryotes. Recently, reduced activity of amino acid sensing SPS pathway was also shown to increase yeast life span. Life span extension by reduced SPS activity requires enhanced NAD+ (nicotinamide adenine dinucleotide, oxidized form) and nicotinamide riboside (NR, a NAD+ precursor) homeostasis. Maintaining adequate NAD+ pools has been shown to play key roles in life span extension, but factors regulating NAD+ metabolism and homeostasis are not completely understood. Recently, NAD+ metabolism was also linked to the phosphate (Pi)-sensing PHO pathway in yeast. Canonical PHO activation requires Pi-starvation. Interestingly, NAD+ depletion without Pi-starvation was sufficient to induce PHO activation, increasing NR production and mobilization. Moreover, SPS signaling appears to function in parallel with PHO signaling components to regulate NR/NAD+ homeostasis. These studies suggest that NAD+ metabolism is likely controlled by and/or coordinated with multiple nutrient sensing pathways. Indeed, cross-regulation of PHO, PKA, TOR and Sch9 pathways was reported to potentially affect NAD+ metabolism; though detailed mechanisms remain unclear. This review discusses yeast longevity-related nutrient sensing pathways and possible mechanisms of life span extension, regulation of NAD+ homeostasis, and cross-talk among nutrient sensing pathways and NAD+ homeostasis.
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Affiliation(s)
- Felicia Tsang
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
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Transcriptomic analysis of the role of Rim101/PacC in the adaptation of Ustilago maydis to an alkaline environment. Microbiology (Reading) 2014; 160:1985-1998. [DOI: 10.1099/mic.0.076216-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Alkaline pH triggers an adaptation mechanism in fungi that is mediated by Rim101/PacCp, a zinc finger transcription factor. To identify the genes under its control in Ustilago maydis, we performed microarray analyses, comparing gene expression in a wild-type strain versus a rim101/pacC mutation strain of the fungus. In this study we obtained evidence of the large number of genes regulated mostly directly, but also indirectly (probably through regulation of other transcription factors), by Rim101/PacCp, including proteins involved in a large number of physiological activities of the fungus. Our analyses suggest that the response to alkaline conditions under the control of the Pal/Rim pathway involves changes in the cell wall and plasma membrane through alterations in their lipid, protein and polysaccharide composition, changes in cell polarity, actin cytoskeleton organization, and budding patterns. Also as expected, adaptation involves regulation by Rim101/PacC of genes involved in meiotic functions, such as recombination and segregation, and expression of genes involved in ion and nutrient transport, as well as general vacuole functions.
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The switch from fermentation to respiration in Saccharomyces cerevisiae is regulated by the Ert1 transcriptional activator/repressor. Genetics 2014; 198:547-60. [PMID: 25123508 DOI: 10.1534/genetics.114.168609] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, fermentation is the major pathway for energy production, even under aerobic conditions. However, when glucose becomes scarce, ethanol produced during fermentation is used as a carbon source, requiring a shift to respiration. This adaptation results in massive reprogramming of gene expression. Increased expression of genes for gluconeogenesis and the glyoxylate cycle is observed upon a shift to ethanol and, conversely, expression of some fermentation genes is reduced. The zinc cluster proteins Cat8, Sip4, and Rds2, as well as Adr1, have been shown to mediate this reprogramming of gene expression. In this study, we have characterized the gene YBR239C encoding a putative zinc cluster protein and it was named ERT1 (ethanol regulated transcription factor 1). ChIP-chip analysis showed that Ert1 binds to a limited number of targets in the presence of glucose. The strongest enrichment was observed at the promoter of PCK1 encoding an important gluconeogenic enzyme. With ethanol as the carbon source, enrichment was observed with many additional genes involved in gluconeogenesis and mitochondrial function. Use of lacZ reporters and quantitative RT-PCR analyses demonstrated that Ert1 regulates expression of its target genes in a manner that is highly redundant with other regulators of gluconeogenesis. Interestingly, in the presence of ethanol, Ert1 is a repressor of PDC1 encoding an important enzyme for fermentation. We also show that Ert1 binds directly to the PCK1 and PDC1 promoters. In summary, Ert1 is a novel factor involved in the regulation of gluconeogenesis as well as a key fermentation gene.
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31
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Thepnok P, Ratanakhanokchai K, Soontorngun N. The novel zinc cluster regulator Tog1 plays important roles in oleate utilization and oxidative stress response in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2014; 450:1276-82. [PMID: 24998441 DOI: 10.1016/j.bbrc.2014.06.128] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 06/25/2014] [Indexed: 11/29/2022]
Abstract
Many zinc cluster proteins have been shown to play a role in the transcriptional regulation of glucose-repressible genes during glucose exhaustion and diauxic shift. Here, we studied an additional member of this family called Yer184c (herein called Tog1) for transcriptional regulator of oleate. Our results showed that a Δtog1 strain displays impaired growth with several non-fermentable carbons. Tog1 is also implicated in oxidative stress tolerance. Importantly, during the glucose-oleate shift, combined results from quantitative real time-PCR and chromatin immunoprecipitation (ChIP) experiments showed that Tog1 acts as a direct activator of oleate utilizing genes, encoded key enzymes in β-Oxidation and NADPH regeneration (POX1, FOX2, POT1 and IDP2), the glyoxylate shunt (MLS1 and ICL1), and gluconeogenesis (PCK1 and FBP1). A transmission electron microscopy (TEM) analysis of the Δtog1 strain assayed with oleate also revealed a substantial decrease in peroxisome abundance that is vital for fatty acid oxidation. Overall, our results clearly demonstrated that Tog1 is a newly characterized zinc cluster regulator that functions in the complex network of non-fermentable carbon metabolism in Saccharomyces cerevisiae.
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Affiliation(s)
- Piyasuda Thepnok
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, 49 Tianthalay Road, Tha Kham, Bangkhuntian, Bangkok 10150, Thailand
| | - Khanok Ratanakhanokchai
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, 49 Tianthalay Road, Tha Kham, Bangkhuntian, Bangkok 10150, Thailand
| | - Nitnipa Soontorngun
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, 49 Tianthalay Road, Tha Kham, Bangkhuntian, Bangkok 10150, Thailand.
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Crespo-Sempere A, Martínez-Culebras P, González-Candelas L. The loss of the inducible Aspergillus carbonarius MFS transporter MfsA leads to ochratoxin A overproduction. Int J Food Microbiol 2014; 181:1-9. [DOI: 10.1016/j.ijfoodmicro.2014.04.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 04/01/2014] [Accepted: 04/10/2014] [Indexed: 11/24/2022]
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Liu G, Marras A, Nielsen J. The future of genome-scale modeling of yeast through integration of a transcriptional regulatory network. QUANTITATIVE BIOLOGY 2014. [DOI: 10.1007/s40484-014-0027-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Carreras-Villaseñor N, Esquivel-Naranjo EU, Villalobos-Escobedo JM, Abreu-Goodger C, Herrera-Estrella A. The RNAi machinery regulates growth and development in the filamentous fungusTrichoderma atroviride. Mol Microbiol 2013; 89:96-112. [DOI: 10.1111/mmi.12261] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2013] [Indexed: 12/18/2022]
Affiliation(s)
- Nohemi Carreras-Villaseñor
- Laboratorio Nacional de Genómica para la Biodiversidad; Cinvestav Sede Irapuato; Km 9.6 Libramiento Norte Carretera Irapuato-León; 36821; Irapuato; Gto.; Mexico
| | - Edgardo U. Esquivel-Naranjo
- Laboratorio Nacional de Genómica para la Biodiversidad; Cinvestav Sede Irapuato; Km 9.6 Libramiento Norte Carretera Irapuato-León; 36821; Irapuato; Gto.; Mexico
| | - J. Manuel Villalobos-Escobedo
- Laboratorio Nacional de Genómica para la Biodiversidad; Cinvestav Sede Irapuato; Km 9.6 Libramiento Norte Carretera Irapuato-León; 36821; Irapuato; Gto.; Mexico
| | - Cei Abreu-Goodger
- Laboratorio Nacional de Genómica para la Biodiversidad; Cinvestav Sede Irapuato; Km 9.6 Libramiento Norte Carretera Irapuato-León; 36821; Irapuato; Gto.; Mexico
| | - Alfredo Herrera-Estrella
- Laboratorio Nacional de Genómica para la Biodiversidad; Cinvestav Sede Irapuato; Km 9.6 Libramiento Norte Carretera Irapuato-León; 36821; Irapuato; Gto.; Mexico
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Nargang FE, Adames K, Rüb C, Cheung S, Easton N, Nargang CE, Chae MS. Identification of genes required for alternative oxidase production in the Neurospora crassa gene knockout library. G3 (BETHESDA, MD.) 2012; 2:1345-56. [PMID: 23173086 PMCID: PMC3484665 DOI: 10.1534/g3.112.004218] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Accepted: 09/04/2012] [Indexed: 01/22/2023]
Abstract
The alternative oxidase (AOX) of Neurospora crassa transfers electrons from ubiquinol to oxygen. The enzyme is not expressed under normal conditions. However, when the function of the standard electron transport chain is compromised, AOX is induced, providing cells with a means to continue respiration and growth. Induction of the enzyme represents a form of retrograde regulation because AOX is encoded by a nuclear gene that responds to signals produced from inefficiently functioning mitochondria. To identify genes required for AOX expression, we have screened the N. crassa gene knockout library for strains that are unable to grow in the presence of antimycin A, an inhibitor of complex III of the standard electron transport chain. From the 7800 strains containing knockouts of different genes, we identified 62 strains that have reduced levels of AOX when grown under conditions known to induce the enzyme. Some strains have virtually no AOX, whereas others have only a slight reduction of the protein. A broad range of seemingly unrelated functions are represented in the knockouts. For example, we identified transcription factors, kinases, the mitochondrial import receptor Tom70, three subunits of the COP9 signalosome, a monothiol glutaredoxin, and several hypothetical proteins as being required for wild-type levels of AOX production. Our results suggest that defects in many signaling or metabolic pathways have a negative effect on AOX expression and imply that complex systems control production of the enzyme.
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Affiliation(s)
- Frank E Nargang
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
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Pang CNI, Goel A, Li SS, Wilkins MR. A multidimensional matrix for systems biology research and its application to interaction networks. J Proteome Res 2012; 11:5204-20. [PMID: 22979997 DOI: 10.1021/pr300405y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A multidimensional matrix containing 76 parameters from 21 transcriptomics, proteomics, interactomics, phenotypic and sequence-based data sets, in which each data set covered most of the Saccharomyces cerevisiae proteome, was compiled for systems biology research. The maximal information coefficient (MIC) was used to measure correlations between every pair of parameters. Out of 2850 possible comparisons, 340 pairs of variables (12%) showed statistically significant MIC scores. There were 321 relationships that were expected; these included relationships within physicochemical parameters of proteins, between abundance levels of genes/proteins and expression noise, and between different types of intracellular networks. We found 19 potentially novel relationships between different types of "-omics" data. The strongest of these involved genetic interaction networks, which were correlated with pleiotropy and cell-to-cell variability in protein expression. Protein disorder also showed a number of significant relationships with protein abundance, signaling and regulatory networks. Significant cross-talk was seen between the signaling and kinase interaction networks. Investigation of this revealed densely connected kinase clusters and significant signaling between them, along with signaling centers that act as integrators or broadcasters of intracellular information. These centers may allow for redundancy and a means of dampening noise in networks under a variety of genetic or environmental perturbations.
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Affiliation(s)
- Chi Nam Ignatius Pang
- Systems Biology Initiative and School of Biotechnology and Biomolecular Sciences, The University of New South Wales, New South Wales, Australia
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Sellam A, Tebbji F, Whiteway M, Nantel A. A novel role for the transcription factor Cwt1p as a negative regulator of nitrosative stress in Candida albicans. PLoS One 2012; 7:e43956. [PMID: 22952822 PMCID: PMC3430608 DOI: 10.1371/journal.pone.0043956] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 07/27/2012] [Indexed: 11/21/2022] Open
Abstract
The ability of Candida albicans to survive in the presence of nitrosative stress during the initial contact with the host immune system is crucial for its ability to colonize mammalian hosts. Thus, this fungus must activate robust mechanisms to neutralize and repair nitrosative-induced damage. Until now, very little was known regarding the regulatory circuits associated with reactive nitrogen species detoxification in fungi. To gain insight into the transcriptional regulatory networks controlling nitrosative stress response (NRS) in C. albicans a compilation of transcriptional regulator-defective mutants were screened. This led to the identification of Cwt1p as a negative regulator of NSR. By combining genome-wide location and expression analyses, we have characterized the Cwt1p regulon and demonstrated that Cwt1p is directly required for proper repression of the flavohemoglobin Yhb1p, a key NO-detoxification enzyme. Furthermore, Cwt1p operates both by activating and repressing genes of specific functions solicited upon NSR. Additionally, we used Gene Set Enrichment Analysis to reinvestigate the C. albicans NSR-transcriptome and demonstrate a significant similarity with the transcriptional profiles of C. albicans interacting with phagocytic host-cells. In summary, we have characterized a novel negative regulator of NSR and bring new insights into the transcriptional regulatory network governing fungal NSR.
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Affiliation(s)
- Adnane Sellam
- Institute for Research in Immunology and Cancer (IRIC), University of Montreal, Montréal, QC, Canada
- * E-mail: (AS); (AN)
| | - Faiza Tebbji
- Biotechnology Research Institute, National Research Council of Canada, Montréal, QC, Canada
- Department of Biology, McGill University, Montréal, QC, Canada
| | - Malcolm Whiteway
- Biotechnology Research Institute, National Research Council of Canada, Montréal, QC, Canada
- Department of Biology, McGill University, Montréal, QC, Canada
| | - André Nantel
- Biotechnology Research Institute, National Research Council of Canada, Montréal, QC, Canada
- Department of Anatomy and Cell Biology, McGill University, Montréal, QC, Canada
- * E-mail: (AS); (AN)
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Soontorngun N, Baramee S, Tangsombatvichit C, Thepnok P, Cheevadhanarak S, Robert F, Turcotte B. Genome-wide location analysis reveals an important overlap between the targets of the yeast transcriptional regulators Rds2 and Adr1. Biochem Biophys Res Commun 2012; 423:632-7. [PMID: 22687600 DOI: 10.1016/j.bbrc.2012.05.151] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 05/26/2012] [Indexed: 10/28/2022]
Abstract
Upon glucose depletion, a massive reprogramming of gene expression occurs in the yeast Saccharomyces cerevisiae for the use of alternate carbon sources such as the nonfermentable compounds ethanol and glycerol. This process is mediated by the master kinase Snf1 that controls the activity of various targets including the transcriptional regulators Cat8, Sip4 and Adr1. We have recently identified Rds2 as an additional player in this pathway. Here, we have performed genome-wide location analysis of Rds2 in cells grown in the presence of glycerol. We show that Rds2 binds to promoters of genes involved in gluconeogenesis, the glyoxylate shunt, and the TCA cycle as well as some genes encoding mitochondrial components or some involved in the stress response. Interestingly, we also detected Rds2 at the promoters of SIP4, ADR1 and HAP4 which encodes the limiting subunit of the Hap2/3/4/5 complex, a regulator of respiration. Strikingly, we observed an important overlap between the targets of Rds2 and Adr1. Finally, we provide a model to account for the complex interplay among these transcriptional regulators.
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Affiliation(s)
- Nitnipa Soontorngun
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, 49 Tianthalay Road, Tha Kham, Bang Khuntian, Bangkok 10150, Thailand.
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Integrated analysis of transcriptome and lipid profiling reveals the co-influences of inositol–choline and Snf1 in controlling lipid biosynthesis in yeast. Mol Genet Genomics 2012; 287:541-54. [DOI: 10.1007/s00438-012-0697-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 05/08/2012] [Indexed: 01/31/2023]
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Suzuki Y, Murray SL, Wong KH, Davis MA, Hynes MJ. Reprogramming of carbon metabolism by the transcriptional activators AcuK and AcuM in Aspergillus nidulans. Mol Microbiol 2012; 84:942-64. [DOI: 10.1111/j.1365-2958.2012.08067.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Moisset P, Vaisman D, Cintolesi A, Urrutia J, Rapaport I, Andrews B, Asenjo J. Continuous modeling of metabolic networks with gene regulation in yeast and in vivo determination of rate parameters. Biotechnol Bioeng 2012; 109:2325-39. [DOI: 10.1002/bit.24503] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 03/13/2012] [Accepted: 03/14/2012] [Indexed: 11/12/2022]
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Mapping the interaction of Snf1 with TORC1 in Saccharomyces cerevisiae. Mol Syst Biol 2011; 7:545. [PMID: 22068328 PMCID: PMC3261716 DOI: 10.1038/msb.2011.80] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 09/29/2011] [Indexed: 01/09/2023] Open
Abstract
Nutrient sensing and coordination of metabolic pathways are crucial functions for living cells. A combined analysis of the yeast transcriptome, phosphoproteome and metabolome is used to investigate the interactions between the Snf1 and TORC1 pathways under nutrient-limited conditions. Snf1 regulates a broad range of biological processes, while target of rapamycin complex 1 (TORC1) seems to be repressed under both glucose- and ammonium-limited conditions. Snf1 has a role in regulating amino acids by upregulating the NADP+-dependent glutamate dehydrogenase (encoded by GDH3) under glucose-limited condition. In addition to the accepted role of Snf1 in regulating fatty acid (FA) metabolism, TORC1 may also regulate FA metabolism. Direct interactions between Snf1 and TORC1 pathways are unlikely under nutrient-limited conditions and TORC1 might be repressed in a manner that is independent of Snf1.
Nutrient sensing and coordination of metabolic pathways are crucial functions for all living cells, but details of the coordination under different environmental conditions remain elusive. We therefore undertook a systems biology approach to investigate the interactions between the Snf1 and the target of rapamycin complex 1 (TORC1) in Saccharomyces cerevisiae. We show that Snf1 regulates a much broader range of biological processes compared with TORC1 under both glucose- and ammonium-limited conditions. We also find that Snf1 has a role in upregulating the NADP+-dependent glutamate dehydrogenase (encoded by GDH3) under derepressing condition, and therefore may also have a role in ammonium assimilation and amino-acid biosynthesis, which can be considered as a convergence of Snf1 and TORC1 pathways. In addition to the accepted role of Snf1 in regulating fatty acid (FA) metabolism, we show that TORC1 also regulates FA metabolism, likely through modulating the peroxisome and β-oxidation. Finally, we conclude that direct interactions between Snf1 and TORC1 pathways are unlikely under nutrient-limited conditions and propose that TORC1 is repressed in a manner that is independent of Snf1.
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Oxidative stress survival in a clinical Saccharomyces cerevisiae isolate is influenced by a major quantitative trait nucleotide. Genetics 2011; 188:709-22. [PMID: 21515583 DOI: 10.1534/genetics.111.128256] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One of the major challenges in characterizing eukaryotic genetic diversity is the mapping of phenotypes that are the cumulative effect of multiple alleles. We have investigated tolerance of oxidative stress in the yeast Saccharomyces cerevisiae, a trait showing phenotypic variation in the population. Initial crosses identified that this is a quantitative trait. Microorganisms experience oxidative stress in many environments, including during infection of higher eukaryotes. Natural variation in oxidative stress tolerance is an important aspect of response to oxidative stress exerted by the human immune system and an important trait in microbial pathogens. A clinical isolate of the usually benign yeast S. cerevisiae was found to survive oxidative stress significantly better than the laboratory strain. We investigated the genetic basis of increased peroxide survival by crossing those strains, phenotyping 1500 segregants, and genotyping of high-survival segregants by hybridization of bulk and single segregant DNA to microarrays. This effort has led to the identification of an allele of the transcription factor Rds2 as contributing to stress response. Rds2 has not previously been associated with the survival of oxidative stress. The identification of its role in the oxidative stress response here is an example of a specific trait that appears to be beneficial to Saccharomyces cerevisiae when growing as a pathogen. Understanding the role of this fungal-specific transcription factor in pathogenicity will be important in deciphering how fungi infect and colonize the human host and could eventually lead to a novel drug target.
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Liu H, Gravelat FN, Chiang LY, Chen D, Vanier G, Ejzykowicz DE, Ibrahim AS, Nierman WC, Sheppard DC, Filler SG. Aspergillus fumigatus AcuM regulates both iron acquisition and gluconeogenesis. Mol Microbiol 2010; 78:1038-54. [PMID: 21062375 DOI: 10.1111/j.1365-2958.2010.07389.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Relatively few transcription factors that govern the virulence of Aspergillus fumigatus are known. We constructed 11 A. fumigatus transcription factor mutants and screened them for altered virulence in Galleria mellonella larvae. We discovered that the zinc cluster transcription factor, AcuM, is essential for maximal virulence in this model, as well as in murine models of haematogenously disseminated and invasive pulmonary aspergillosis. Transcriptional profiling experiments suggested that AcuM suppresses sreA and induces hapX to stimulate expression of genes involved in both reductive iron assimilation and siderophore-mediated iron uptake. Consistent with these results, a ΔacuM mutant had reduced iron incorporation, decreased extracellular siderophore production and impaired capacity to grow under iron-limited conditions. Interestingly, an Aspergillus nidulansΔacuM mutant had normal extracellular siderophore production and growth under iron-limited conditions, indicating that AcuM does not govern iron acquisition in this organism. A. fumigatus AcuM also regulated genes involved in gluconeogenesis, and the ΔacuM mutant had impaired growth on gluconeogenic carbon sources. Deletion of sreA in the ΔacuM mutant restored iron uptake, extracellular siderophore production and virulence, but not the defect in gluconeogenesis. Thus, AcuM represses SreA and thereby induces iron acquisition, a process that is essential for the maximal virulence of A. fumigatus.
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Affiliation(s)
- Hong Liu
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
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Phosphoglycerate mutase knock-out mutant Saccharomyces cerevisiae: Physiological investigation and transcriptome analysis. Biotechnol J 2010; 5:1016-27. [DOI: 10.1002/biot.201000199] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Simicevic J, Deplancke B. DNA-centered approaches to characterize regulatory protein-DNA interaction complexes. MOLECULAR BIOSYSTEMS 2009; 6:462-8. [PMID: 20174675 DOI: 10.1039/b916137f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Gene regulation is mediated by site-specific DNA-binding proteins or transcription factors (TFs), which form protein complexes at regulatory loci either to activate or repress the expression of a target gene. The study of the dynamic properties of these regulatory DNA-binding complexes has so far been dominated by protein-centered methodologies, aiming to characterize the DNA-binding behavior of one specific protein at a time. With the emerging evidence for a role of DNA in allosterically influencing DNA-binding protein complex formation, there is renewed interest in DNA-centered approaches to capture protein complexes on defined regulatory loci and to correlate changes in their composition with alterations in target gene expression. In this review, we present the current state-of-the-art in such DNA-centered approaches and evaluate recent technological improvements in the purification as well as in the identification of regulatory DNA-binding protein complexes within or outside their biological context. Finally, we suggest possible areas of improvement and assess the putative impact of DNA-centered methodologies on the gene regulation field for the forthcoming years.
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Affiliation(s)
- Jovan Simicevic
- Ecole Polytechnique Fédérale de Lausanne, School of Life Sciences, Institute of Bioengineering, Station 15, 1015 Lausanne, Switzerland.
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Chae MS, Nargang FE. Investigation of regulatory factors required for alternative oxidase production in Neurospora crassa. PHYSIOLOGIA PLANTARUM 2009; 137:407-418. [PMID: 19493307 DOI: 10.1111/j.1399-3054.2009.01239.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Alternative oxidase (AOX) has been found in a large number of filamentous fungi and yeasts with the notable exceptions of Saccharomyces cerevisiae and Schizosaccharomyces pombe. In virtually all of these fungi, AOX is induced by stresses on the cell that compromise the efficiency of the standard mitochondrial electron transport chain. As AOX is encoded in the nucleus and the signals that induce its expression originate in mitochondria, induction of the enzyme provides a classic example of retrograde regulation where signals from mitochondria influence the expression of nuclear genes. We have previously isolated mutants in Neurospora crassa that are incapable of inducing AOX. The genes affected in two of these mutants, aod-2 and aod-5, encode zinc cluster transcription factors that act to control expression of the AOX by binding to an alternative oxidase induction motif (AIM) found in the promoter of the AOX structural gene. We have now used pull-down assays and size-exclusion chromatography to demonstrate that the AOD2 and AOD5 proteins physically interact in vitro. In addition, we have shown that a homolog of the RTG2 protein, which is part of a classic retrograde signaling pathway in S. cerevisiae, is not required for AOX regulation in N. crassa.
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Affiliation(s)
- Michael S Chae
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G2E9
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Turcotte B, Liang XB, Robert F, Soontorngun N. Transcriptional regulation of nonfermentable carbon utilization in budding yeast. FEMS Yeast Res 2009; 10:2-13. [PMID: 19686338 DOI: 10.1111/j.1567-1364.2009.00555.x] [Citation(s) in RCA: 171] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Saccharomyces cerevisiae preferentially uses glucose as a carbon source, but following its depletion, it can utilize a wide variety of other carbons including nonfermentable compounds such as ethanol. A shift to a nonfermentable carbon source results in massive reprogramming of gene expression including genes involved in gluconeogenesis, the glyoxylate cycle, and the tricarboxylic acid cycle. This review is aimed at describing the recent progress made toward understanding the mechanism of transcriptional regulation of genes responsible for utilization of nonfermentable carbon sources. A central player for the use of nonfermentable carbons is the Snf1 kinase, which becomes activated under low glucose levels. Snf1 phosphorylates various targets including the transcriptional repressor Mig1, resulting in its inactivation allowing derepression of gene expression. For example, the expression of CAT8, encoding a member of the zinc cluster family of transcriptional regulators, is then no longer repressed by Mig1. Cat8 becomes activated through phosphorylation by Snf1, allowing upregulation of the zinc cluster gene SIP4. These regulators control the expression of various genes including those involved in gluconeogenesis. Recent data show that another zinc cluster protein, Rds2, plays a key role in regulating genes involved in gluconeogenesis and the glyoxylate pathway. Finally, the role of additional regulators such as Adr1, Ert1, Oaf1, and Pip2 is also discussed.
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Affiliation(s)
- Bernard Turcotte
- Department of Medicine, Royal Victoria Hospital, McGill University, Montréal, QC, Canada.
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Mutations in two zinc-cluster proteins activate alternative respiratory and gluconeogenic pathways and restore senescence in long-lived respiratory mutants of Podospora anserina. Genetics 2009; 182:69-78. [PMID: 19255367 DOI: 10.1534/genetics.109.100834] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Podospora anserina, inactivation of the respiratory chain results in a spectacular life-span extension. This inactivation is accompanied by the induction of the alternative oxidase. Although the functional value of this response is evident, the mechanism behind it is far from understood. By screening suppressors able to reduce the life-span extension of cytochrome-deficient mutants, we identified mutations in two zinc-cluster proteins, RSE2 and RSE3, which are conserved in other ascomycetes. These mutations led to the overexpression of the genes encoding the alternative oxidase and the gluconeogenic enzymes, fructose-1, 6 biphosphatase, and pyruvate carboxykinase. Both RSE2 and RSE3 are required for the expression of these genes. We also show that, even in the absence of a respiratory deficiency, the wild-type RSE2 and RSE3 transcription factors are involved in life-span control and their inactivation retards aging. These data are discussed with respect to aging, the regulation of the alternative oxidase, and carbon metabolism.
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Current awareness on yeast. Yeast 2008. [DOI: 10.1002/yea.1563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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