| 1. |
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| 2. |
- Tamás, Markus J., 1970, et al.
(författare)
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Fps1p controls the accumulation and release of the compatible solute glycerol in yeast osmoregulation.
- 1999
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Ingår i: Molecular microbiology. - 0950-382X .- 1365-2958. ; 4, s. 1087-104
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Tidskriftsartikel (refereegranskat)abstract
- The accumulation of compatible solutes, such as glycerol, in the yeast Saccharomyces cerevisiae, is a ubiquitous mechanism in cellular osmoregulation. Here, we demonstrate that yeast cells control glycerol accumulation in part via a regulated, Fps1p-mediated export of glycerol. Fps1p is a member of the MIP family of channel proteins most closely related to the bacterial glycerol facilitators. The protein is localized in the plasma membrane. The physiological role of Fps1p appears to be glycerol export rather than uptake. Fps1 delta mutants are sensitive to hypo-osmotic shock, demonstrating that osmolyte export is required for recovery from a sudden drop in external osmolarity. In wild-type cells, the glycerol transport rate is decreased by hyperosmotic shock and increased by hypo-osmotic shock on a subminute time scale. This regulation seems to be independent of the known yeast osmosensing HOG and PKC signalling pathways. Mutants lacking the unique hydrophilic N-terminal domain of Fps1p, or certain parts thereof, fail to reduce the glycerol transport rate after a hyperosmotic shock. Yeast cells carrying these constructs constitutively release glycerol and show a dominant hyperosmosensitivity, but compensate for glycerol loss after prolonged incubation by glycerol overproduction. Fps1p may be an example of a more widespread class of regulators of osmoadaptation, which control the cellular content and release of compatible solutes.
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| 3. |
- Tamás, Markus J., 1970, et al.
(författare)
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A Short Regulatory Domain Restricts Glycerol Transport through Yeast Fps1p
- 2003
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Ingår i: J. Biol. Chem. ; 278, s. 6337-6345
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Tidskriftsartikel (refereegranskat)abstract
- The controlled export of solutes is crucial for cellular adaptation to hypotonic conditions. In the yeast Saccharomyces cerevisiae glycerol export is mediated by Fps1p, a member of the major intrinsic protein (MIP) family of channel proteins. Here we describe a short regulatory domain that restricts glycerol transport through Fps1p. This domain is required for retention of cellular glycerol under hypertonic stress and hence acquisition of osmotolerance. It is located in the N-terminal cytoplasmic extension close to the first transmembrane domain. Several residues within that domain and its precise position are critical for channel control while the proximal residues 13-215 of the N-terminal extension are not required. The sequence of the regulatory domain and its position are perfectly conserved in orthologs from other yeast species. The regulatory domain has an amphiphilic character, and structural predictions indicate that it could fold back into the membrane bilayer. Remarkably, this domain has structural similarity to the channel forming loops B and E of Fps1p and other glycerol facilitators. Intragenic second-site suppressor mutations of the sensitivity to high osmolarity conferred by truncation of the regulatory domain caused diminished glycerol transport, confirming that elevated channel activity is the cause of the osmosensitive phenotype.
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| 4. |
- Jacobson, Therese, et al.
(författare)
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Cadmium Causes Misfolding and Aggregation of Cytosolic Proteins in Yeast
- 2017
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Ingår i: Molecular and Cellular Biology. - : Informa UK Limited. - 0270-7306 .- 1098-5549. ; 37:17
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Tidskriftsartikel (refereegranskat)abstract
- Cadmium is a highly poisonous metal and is classified as a human carcinogen. While its toxicity is undisputed, the underlying in vivo molecular mechanisms are not fully understood. Here, we demonstrate that cadmium induces aggregation of cytosolic proteins in living Saccharomyces cerevisiae cells. Cadmium primarily targets proteins in the process of synthesis or folding, probably by interacting with exposed thiol groups in not-yet-folded proteins. On the basis of in vitro and in vivo data, we show that cadmium-aggregated proteins form seeds that increase the misfolding of other proteins. Cells that cannot efficiently protect the proteome from cadmium-induced aggregation or clear the cytosol of protein aggregates are sensitized to cadmium. Thus, protein aggregation may contribute to cadmium toxicity. This is the first report on how cadmium causes misfolding and aggregation of cytosolic proteins in vivo. The proposed mechanism might explain not only the molecular basis of the toxic effects of cadmium but also the suggested role of this poisonous metal in the pathogenesis of certain protein-folding disorders.
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| 5. |
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| 6. |
- Weids, Alan J, et al.
(författare)
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Distinct stress conditions result in aggregation of proteins with similar properties.
- 2016
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Protein aggregation is the abnormal association of proteins into larger aggregate structures which tend to be insoluble. This occurs during normal physiological conditions and in response to age or stress-induced protein misfolding and denaturation. In this present study we have defined the range of proteins that aggregate in yeast cells during normal growth and after exposure to stress conditions including an oxidative stress (hydrogen peroxide), a heavy metal stress (arsenite) and an amino acid analogue (azetidine-2-carboxylic acid). Our data indicate that these three stress conditions, which work by distinct mechanisms, promote the aggregation of similar types of proteins probably by lowering the threshold of protein aggregation. The proteins that aggregate during physiological conditions and stress share several features; however, stress conditions shift the criteria for protein aggregation propensity. This suggests that the proteins in aggregates are intrinsically aggregation-prone, rather than being proteins which are affected in a stress-specific manner. We additionally identified significant overlaps between stress aggregating yeast proteins and proteins that aggregate during ageing in yeast and C. elegans. We suggest that similar mechanisms may apply in disease- and non-disease settings and that the factors and components that control protein aggregation may be evolutionary conserved.
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| 7. |
- Adamo, Giusy M, et al.
(författare)
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Amplification of the CUP1 gene is associated with evolution of copper tolerance in Saccharomyces cerevisiae.
- 2012
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Ingår i: Microbiology (Reading, England). - : Microbiology Society. - 1465-2080 .- 1350-0872. ; 158:Pt 9, s. 2325-35
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Tidskriftsartikel (refereegranskat)abstract
- In living organisms, copper (Cu) contributes to essential functions but at high concentrations it may elicit toxic effects. Cu-tolerant yeast strains are of relevance for both biotechnological applications and studying physiological and molecular mechanisms involved in stress resistance. One way to obtain tolerant strains is to exploit experimental methods that rely on the principles of natural evolution (evolutionary engineering) and allow for the development of complex phenotypic traits. However, in most cases, the molecular and physiological basis of the phenotypic changes produced have not yet been unravelled. We investigated the determinants of Cu resistance in a Saccharomyces cerevisiae strain that was evolved to tolerate up to 2.5 g CuSO(4) l(-1) in the culture medium. We found that the content of intracellular Cu and the expression levels of several genes encoding proteins involved in Cu metabolism and oxidative stress response were similar in the Cu-tolerant (evolved) and the Cu-sensitive (non-evolved) strain. The major difference detected in the two strains was the copy number of the gene CUP1, which encodes a metallothionein. In evolved cells, a sevenfold amplification of CUP1 was observed, accounting for its strongly and steadily increased expression. Our results implicate CUP1 in protection of the evolved S. cerevisiae cells against Cu toxicity. In these cells, robustness towards Cu is stably inheritable and can be reproducibly selected by controlling environmental conditions. This finding corroborates the effectiveness of laboratory evolution of whole cells as a tool to develop microbial strains for biotechnological applications.
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| 8. |
- Ahmadpour, Doryaneh, 1973, et al.
(författare)
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The mitogen-activated protein kinase Slt2 modulates arsenite transport through the aquaglyceroporin Fps1
- 2016
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Ingår i: FEBS Letters. - : Wiley. - 0014-5793 .- 1873-3468. ; 590:20, s. 3649-3659
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Tidskriftsartikel (refereegranskat)abstract
- © 2016 Federation of European Biochemical Societies Arsenite is widely present in nature; therefore, cells have evolved mechanisms to prevent arsenite influx and promote efflux. In yeast (Saccharomyces cerevisiae), the aquaglyceroporin Fps1 mediates arsenite influx and efflux. The mitogen-activated protein kinase (MAPK) Hog1 has previously been shown to restrict arsenite influx through Fps1. In this study, we show that another MAPK, Slt2, is transiently phosphorylated in response to arsenite influx. Our findings indicate that the protein kinase activity of Slt2 is required for its role in arsenite tolerance. While Hog1 prevents arsenite influx via phosphorylation of T231 at the N-terminal domain of Fps1, Slt2 promotes arsenite efflux through phosphorylation of S537 at the C terminus. Our data suggest that Slt2 physically interacts with Fps1 and that this interaction depends on phosphorylation of S537. We hypothesize that Hog1 and Slt2 may affect each other's binding to Fps1, thereby controlling the opening and closing of the channel.
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| 9. |
- Ahmadpour, Doryaneh, 1973, et al.
(författare)
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Yeast reveals unexpected roles and regulatory features of aquaporins and aquaglyceroporins
- 2014
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Ingår i: Biochimica et Biophysica Acta. General Subjects. - : Elsevier BV. - 0304-4165 .- 1872-8006 .- 0006-3002. ; 1840:5, s. 1482-1491
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Forskningsöversikt (refereegranskat)abstract
- Background: The yeast Saccharomyces cerevisiae provides unique opportunities to study roles and regulation of aqua/glyceroporins using frontline tools of genetics and genomics as well as molecular cell and systems biology. Scope of review: S. cerevisiae has two similar orthodox aquaporins. Based on phenotypes mediated by gene deletion or overexpression as well as on their expression pattern, the yeast aquaporins play important roles in key aspects of yeast biology: establishment of freeze tolerance, during spore formation as well as determination of cell surface properties for substrate adhesion and colony formation. Exactly how the aquaporins perform those roles and the mechanisms that regulate their function under such conditions remain to be elucidated. S. cerevisiae also has two different aquaglyceroporins. While the role of one of them, Yfl054c, remains to be determined, Fps1 plays critical roles in osmoregulation by controlling the accumulation of the osmolyte glycerol. Fpsl communicates with two osmo-sensing MAPK signalling pathways to perform its functions but the details of Fps1 regulation remain to be determined. Major conclusions: Several phenotypes associated with aqua/glyceroporin function in yeasts have been established. However, how water and glycerol transport contribute to the observed effects is not understood in detail. Also many of the basic principles of regulation of yeast aqua/glyceroporins remain to be elucidated. General significance: Studying the yeast aquaporins and aquaglyceroporins offers rich insight into the life style, evolution and adaptive responses of yeast and rewards us with discoveries of unexpected roles and regulatory mechanisms of members of this ancient protein family. This article is part of a Special Issue entitled Aquaporins. (c) 2013 Elsevier B.V. All rights reserved.
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| 10. |
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| 11. |
- Andersson, Stefanie, 1989, et al.
(författare)
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Genome-wide imaging screen uncovers molecular determinants of arsenite-induced protein aggregation and toxicity
- 2021
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Ingår i: Journal of Cell Science. - : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 134:11
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Tidskriftsartikel (refereegranskat)abstract
- The toxic metalloid arsenic causes widespread misfolding and aggregation of cellular proteins. How these protein aggregates are formed in vivo, the mechanisms by which they affect cells and how cells prevent their accumulation is not fully understood. To find components involved in these processes, we performed a genome-wide imaging screen and identified Saccharomyces cerevisiae deletion mutants with either enhanced or reduced protein aggregation levels during arsenite exposure. We show that many of the identified factors are crucial to safeguard protein homeostasis (proteostasis) and to protect cells against arsenite toxicity. The hits were enriched for various functions including protein biosynthesis and transcription, and dedicated follow-up experiments highlight the importance of accurate transcriptional and translational control for mitigating protein aggregation and toxicity during arsenite stress. Some of the hits are associated with pathological conditions, suggesting that arsenite-induced protein aggregation may affect disease processes. The broad network of cellular systems that impinge on proteostasis during arsenic stress identified in this current study provides a valuable resource and a framework for further elucidation of the mechanistic details of metalloid toxicity and pathogenesis. This article has an associated First Person interview with the first authors of the paper.
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| 12. |
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| 13. |
- Bienert, Gern, 2008, et al.
(författare)
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A subgroup of plant aquaporins facilitate the bi-directional diffusion of As(OH)3 and Sb(OH)3 across membranes
- 2008
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Ingår i: BMC Biology. - : Springer Science and Business Media LLC. - 1741-7007. ; 6:26
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Tidskriftsartikel (refereegranskat)abstract
- Background Arsenic is a toxic and highly abundant metalloid that endangers human health through drinking water and the food chain. The most common forms of arsenic in the environment are arsenate (As(V)) and arsenite (As(III)). As(V) is a non-functional phosphate analog that enters the food chain via plant phosphate transporters. Inside cells, As(V) becomes reduced to As(III) for subsequent extrusion or compartmentation. Although much is known about As(III) transport and handling in microbes and mammals, the transport systems for As(III) have not yet been characterized in plants. Results Here we show that the Nodulin26-like Intrinsic Proteins (NIPs) AtNIP5;1 and AtNIP6;1 from Arabidopsis thaliana, OsNIP2;1 and OsNIP3;2 from Oryza sativa, and LjNIP5;1 and LjNIP6;1 from Lotus japonicus are bi-directional As(III) channels. Expression of these NIPs sensitized yeast cells to As(III) and antimonite (Sb(III)), and direct transport assays confirmed their ability to facilitate As(III) transport across cell membranes. On medium containing As(V), expression of the same NIPs improved yeast growth, probably due to increased As(III) efflux. Our data furthermore provide evidence that NIPs can discriminate between highly similar substrates and that they may have differential preferences in the direction of transport. A subgroup of As(III) permeable channels that group together in a phylogenetic tree required N-terminal truncation for functional expression in yeast. Conclusion This is the first molecular identification of plant As(III) transport systems and we propose that metalloid transport through NIPs is a conserved and ancient feature. Our observations are potentially of great importance for improved remediation and tolerance of plants, and may provide a key to the development of low arsenic crops for food production.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
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| 18. |
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| 19. |
- Di, Yujun, 1973, et al.
(författare)
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Regulation of the arsenic-responsive transcription factor Yap8p involves the ubiquitin-proteasome pathway
- 2007
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Ingår i: Journal of Cell Science. ; 120, s. 256-264
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Tidskriftsartikel (refereegranskat)abstract
- Toxic metals are ubiquitous in the environment and all organisms possess systems to evade toxicity and acquire tolerance. The Saccharomyces cerevisiae AP-1-like protein Yap8p (systematic name YPR199c; also known as Acr1p and Arr1p) confers arsenic tolerance by stimulating enhanced transcription of the arsenic-specific detoxification genes ACR2 and ACR3. Here, we report that Yap8p is regulated at the level of degradation. We show that Yap8p is stabilized in arsenite-exposed cells in a time- and dose-dependent manner. Yap8p degradation proceeds through the ubiquitin-proteasome pathway and is dependent on the ubiquitin-conjugating enzyme Ubc4p. Further, we show that mutants that are defective in the ubiquitin-proteasome pathway display increased Yap8p levels and elevated expression of the Yap8p gene-target ACR3. Yap8p forms homodimers in vivo but dimerization is not regulated by arsenite. Instead, arsenite-stimulated Yap8p stabilization and transcriptional activation of ACR3 requires critical cysteine residues within Yap8p. Collectively, our data is consistent with a model where Yap8p is degraded by the ubiquitin-proteasome pathway in untreated cells, whereas arsenite-exposure results in Yap8p stabilization and gene activation. In this way, regulated degradation contributes to Yap8p control.
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| 20. |
- Dinér, Peter, 1976, et al.
(författare)
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Design, synthesis, and characterization of a highly effective Hog1 inhibitor: a powerful tool for analyzing MAP kinase signaling in yeast.
- 2011
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 6:5
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Tidskriftsartikel (refereegranskat)abstract
- The Saccharomyces cerevisiae High-Osmolarity Glycerol (HOG) pathway is a conserved mitogen-activated protein kinase (MAPK) signal transduction system that often serves as a model to analyze systems level properties of MAPK signaling. Hog1, the MAPK of the HOG-pathway, can be activated by various environmental cues and it controls transcription, translation, transport, and cell cycle adaptations in response to stress conditions. A powerful means to study signaling in living cells is to use kinase inhibitors; however, no inhibitor targeting wild-type Hog1 exists to date. Herein, we describe the design, synthesis, and biological application of small molecule inhibitors that are cell-permeable, fast-acting, and highly efficient against wild-type Hog1. These compounds are potent inhibitors of Hog1 kinase activity both in vitro and in vivo. Next, we use these novel inhibitors to pinpoint the time of Hog1 action during recovery from G(1) checkpoint arrest, providing further evidence for a specific role of Hog1 in regulating cell cycle resumption during arsenite stress. Hence, we describe a novel tool for chemical genetic analysis of MAPK signaling and provide novel insights into Hog1 action.
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| 21. |
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| 22. |
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| 23. |
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| 24. |
- Geijer, Cecilia, 1980, et al.
(författare)
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Yeast Aquaglyceroporins Use the Transmembrane Core to Restrict Glycerol Transport
- 2012
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 287:28, s. 23562-23570
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Tidskriftsartikel (refereegranskat)abstract
- Aquaglyceroporins are transmembrane proteins belonging to the family of aquaporins, which facilitate the passage of specific uncharged solutes across membranes of cells. The yeast aquaglyceroporin Fps1 is important for osmoadaptation by regulating intracellular glycerol levels during changes in external osmolarity. Upon high osmolarity conditions, yeast accumulates glycerol by increased production of the osmolyte and by restricting glycerol efflux through Fps1. The extended cytosolic termini of Fps1 contain short domains that are important for regulating glycerol flux through the channel. Here we show that the transmembrane core of the protein plays an equally important role. The evidence is based on results from an intragenic suppressor mutation screen and domain swapping between the regulated variant of Fps1 from Saccharomyces cerevisiae and the hyperactive Fps1 ortholog from Ashbya gossypii. This suggests a novel mechanism for regulation of glycerol flux in yeast, where the termini alone are not sufficient to restrict Fps1 transport. We propose that glycerol flux through the channel is regulated by interplay between the transmembrane helices and the termini. This mechanism enables yeast cells to fine-tune intracellular glycerol levels at a wide range of extracellular osmolarities.
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| 25. |
- Gjuvsland, Arne B, et al.
(författare)
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Disentangling genetic and epigenetic determinants of ultrafast adaptation.
- 2016
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Ingår i: Molecular systems biology. - : EMBO. - 1744-4292. ; 12:12
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Tidskriftsartikel (refereegranskat)abstract
- A major rationale for the advocacy of epigenetically mediated adaptive responses is that they facilitate faster adaptation to environmental challenges. This motivated us to develop a theoretical-experimental framework for disclosing the presence of such adaptation-speeding mechanisms in an experimental evolution setting circumventing the need for pursuing costly mutation-accumulation experiments. To this end, we exposed clonal populations of budding yeast to a whole range of stressors. By growth phenotyping, we found that almost complete adaptation to arsenic emerged after a few mitotic cell divisions without involving any phenotypic plasticity. Causative mutations were identified by deep sequencing of the arsenic-adapted populations and reconstructed for validation. Mutation effects on growth phenotypes, and the associated mutational target sizes were quantified and embedded in data-driven individual-based evolutionary population models. We found that the experimentally observed homogeneity of adaptation speed and heterogeneity of molecular solutions could only be accounted for if the mutation rate had been near estimates of the basal mutation rate. The ultrafast adaptation could be fully explained by extensive positive pleiotropy such that all beneficial mutations dramatically enhanced multiple fitness components in concert. As our approach can be exploited across a range of model organisms exposed to a variety of environmental challenges, it may be used for determining the importance of epigenetic adaptation-speeding mechanisms in general.
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| 26. |
- Hedfalk, Kristina, 1969, et al.
(författare)
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A Regulatory Domain in the C-terminal Extension of the Yeast Glycerol Channel Fps1p
- 2004
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Ingår i: Journal of biological chemistry. ; 279:15, s. 14954-14960
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Tidskriftsartikel (refereegranskat)abstract
- The Saccharomyces cerevisiae gene FPS1 encodes an aquaglyceroporin of the major intrinsic protein (MIP) family. The main function of Fps1p seems to be the efflux of glycerol in the adaptation of the yeast cell to lower external osmolarity. Fps1p is an atypical member of the family, because the protein is much larger (669 amino acids) than most MIPs due to long hydrophilic extensions in both termini. We have shown previously that a short domain in the N-terminal extension of the protein is required for restricting glycerol transport through the channel (Tamás, M. J., Karlgren, S., Bill, R. M., Hedfalk, K., Allegri, L., Ferreira, M., Thevelein, J. M., Rydström, J., Mullins, J. G. L., and Hohmann, S. (2003) J. Biol. Chem. 278, 63376345). Deletion of the N-terminal domain results in an unregulated channel, loss of glycerol, and osmosensitivity. In this work we have investigated the role of the Fps1p C terminus (139 amino acids). A set of eight truncations has been constructed and tested in vivo in a yeast fps1 strain. We have performed growth tests, membrane localization following cell fractionation, and glycerol accumulation measurements as well as an investigation of the osmotic stress response. Our results show that the C-terminal extension is also involved in restricting transport through Fps1p. We have identified a sequence of 12 amino acids, residues 535546, close to the sixth transmembrane domain. This element seems to be important for controlling Fps1p function. Similar to the N-terminal domain, the C-terminal domain is amphiphilic and has a potential to dip into the membrane
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| 27. |
- Hua, Sansan, et al.
(författare)
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Differential contributions of the proteasome, autophagy, and chaperones to the clearance of arsenite-induced protein aggregates in yeast.
- 2022
-
Ingår i: The Journal of biological chemistry. - : Elsevier BV. - 1083-351X .- 0021-9258. ; 298:12
-
Tidskriftsartikel (refereegranskat)abstract
- The poisonous metalloid arsenite induces widespread misfolding and aggregation of nascent proteins invivo, and this mode of toxic action might underlie its suspected role in the pathology of certain protein misfolding diseases. Evolutionarily conserved protein quality-control systems protect cells against arsenite-mediated proteotoxicity, and herein, we systematically assessed the contribution of the ubiquitin-proteasome system, the autophagy-vacuole pathway, and chaperone-mediated disaggregation to the clearance of arsenite-induced protein aggregates in Saccharomyces cerevisiae. We show that the ubiquitin-proteasome system is the main pathway that clears aggregates formed during arsenite stress and that cells depend on this pathway for optimal growth. The autophagy-vacuole pathway and chaperone-mediated disaggregation both contribute to clearance, but their roles appear less prominent than the ubiquitin-proteasome system. Our invitro assays with purified components of the yeast disaggregating machinery demonstrated that chaperone binding to aggregates formed in the presence of arsenite is impaired. Hsp104 and Hsp70 chaperone activity was unaffected by arsenite, suggesting that this metalloid influences aggregate structure, making them less accessible for chaperone-mediated disaggregation. We further show that the defect in chaperone-mediated refolding of a model protein was abrogated in a cysteine-free version of the substrate, suggesting that arsenite directly modifies cysteines in non-native target proteins. In conclusion, our study sheds novel light on the differential contributions of protein quality-control systems to aggregate clearance and cell proliferation and extends our understanding of how these systems operate during arsenite stress.
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| 28. |
- Hörberg, Johanna, et al.
(författare)
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Sequence-specific dynamics of DNA response elements and their flanking sites regulate the recognition by AP-1 transcription factors.
- 2021
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Ingår i: Nucleic acids research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 49:16, s. 9280-9293
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Tidskriftsartikel (refereegranskat)abstract
- Activator proteins 1 (AP-1) comprise one of the largest families of eukaryotic basic leucine zipper transcription factors. Despite advances in the characterization of AP-1 DNA-binding sites, our ability to predict new binding sites and explain how the proteins achieve different gene expression levels remains limited. Here we address the role of sequence-specific DNA flexibility for stability and specific binding of AP-1 factors, using microsecond-long molecular dynamics simulations. As a model system, we employ yeast AP-1 factor Yap1 binding to three different response elements from two genetic environments. Our data show that Yap1 actively exploits the sequence-specific flexibility of DNA within the response element to form stable protein-DNA complexes. The stability also depends on the four to six flanking nucleotides, adjacent to the response elements. The flanking sequences modulate the conformational adaptability of the response element, making it more shape-efficient to form specific contacts with the protein. Bioinformatics analysis of differential expression of the studied genes supports our conclusions: the stability of Yap1-DNA complexes, modulated by the flanking environment, influences the gene expression levels. Our results provide new insights into mechanisms of protein-DNA recognition and the biological regulation of gene expression levels in eukaryotes.
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| 29. |
- Ibstedt, Sebastian, 1983, et al.
(författare)
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Global analysis of protein aggregation in Saccharomyces cerevisiae
- 2013
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Ingår i: Yeast. - : Wiley. - 0749-503X. ; 30:S1
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Konferensbidrag (refereegranskat)abstract
- Protein misfolding and aggregation is associated with various neurodegenerative and age-related disorders. In this study, we isolated aggregation-prone proteins from Saccharomyces cerevisiae and identified several physicochemical characteristics that are linked to physiological, arsenite-induced and age-dependent protein aggregation. Protein abundance, translation rate, physical and genetic interactions, and certain structural properties are correlated with increased aggregation propensity. Arsenite lowers the “threshold” for protein aggregation; hence the predisposition to aggregate increases under stress. We show that arsenite-aggregated proteins are enriched for chaperone interactions, substantiating our previous observations that arsenite interferes with chaperone activity in vivo. Our results suggest that the majority of protein aggregation is co-translational and that yeast decrease expression of aggregation-prone proteins during stress, possibly as a mechanism to prevent excessive accumulation of protein aggregates. Finally, we show that several aggregation-prone yeast proteins have human homologs that are implicated in misfolding diseases. Taken together, this study provides novel insights into the rules that govern protein aggregation in yeast cells.
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| 30. |
- Ibstedt, Sebastian, 1983, et al.
(författare)
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Global analysis of protein aggregation in yeast during physiological conditions and arsenite stress.
- 2014
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Ingår i: Biology open. - : The Company of Biologists. - 2046-6390. ; 3:10, s. 913-923
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Tidskriftsartikel (refereegranskat)abstract
- Protein aggregation is a widespread phenomenon in cells and associated with pathological conditions. Yet, little is known about the rules that govern protein aggregation in living cells. In this study, we biochemically isolated aggregation-prone proteins and used computational analyses to identify characteristics that are linked to physiological and arsenite-induced aggregation in living yeast cells. High protein abundance, extensive physical interactions, and certain structural properties are positively correlated with an increased aggregation propensity. The aggregated proteins have high translation rates and are substrates of ribosome-associated Hsp70 chaperones, indicating that they are susceptible for aggregation primarily during translation/folding. The aggregation-prone proteins are enriched for multiple chaperone interactions, thus high protein abundance is probably counterbalanced by molecular chaperones to allow soluble expression in vivo. Our data support the notion that arsenite interferes with chaperone activity and indicate that arsenite-aggregated proteins might engage in extensive aberrant protein-protein interactions. Expression of aggregation-prone proteins is down-regulated during arsenite stress, possibly to prevent their toxic accumulation. Several aggregation-prone yeast proteins have human homologues that are implicated in misfolding diseases, suggesting that similar mechanisms may apply in disease- and non-disease settings.
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| 31. |
- Ilina, Yulia, et al.
(författare)
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Characterization of the DNA-binding motif of the arsenic-responsive transcription factor Yap8p.
- 2008
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Ingår i: The Biochemical journal. - 1470-8728. ; 415:3, s. 467-75
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Tidskriftsartikel (refereegranskat)abstract
- Saccharomyces cerevisiae uses several mechanisms for arsenic detoxification including the arsenate reductase Acr2p and the arsenite efflux protein Acr3p. ACR2 and ACR3 are transcribed in opposite directions from the same promoter and expression of these genes is regulated by the AP-1 (activator protein 1)-like transcription factor Yap8p. Yap8p has been shown to permanently associate with this promoter and to stimulate ACR2/ACR3 expression in response to arsenic. In the present study we characterized the DNA sequence that is targeted by Yap8p. We show that Yap8p binds to a pseudo-palindromic TGATTAATAATCA sequence that is related to, but distinct from, the sequence recognized by other fungal AP-1 proteins. Probing the promoter by mutational analysis, we confirm the importance of the TTAATAA core element and pin-point nucleotides that flank this element as crucial for Yap8p binding and in vivo activation of ACR3 expression. A genome-wide search for this element combined with global gene expression analysis indicates that the principal function of Yap8p is to control expression of ACR2 and ACR3. We conclude that Yap8p and other yeast AP-1 proteins require distinct DNA-binding motifs to induce gene expression and propose that this fact contributed towards a separation of function between AP-1 proteins during evolution.
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| 32. |
- Isik, E., et al.
(författare)
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Identification of novel arsenic resistance genes in yeast
- 2022
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Ingår i: Microbiologyopen. - : Wiley. - 2045-8827. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Arsenic is a toxic metalloid that affects human health by causing numerous diseases and by being used in the treatment of acute promyelocytic leukemia. Saccharomyces cerevisiae (budding yeast) has been extensively utilized to elucidate the molecular mechanisms underlying arsenic toxicity and resistance in eukaryotes. In this study, we applied a genomic DNA overexpression strategy to identify yeast genes that provide arsenic resistance in wild-type and arsenic-sensitive S. cerevisiae cells. In addition to known arsenic-related genes, our genetic screen revealed novel genes, including PHO86, VBA3, UGP1, and TUL1, whose overexpression conferred resistance. To gain insights into possible resistance mechanisms, we addressed the contribution of these genes to cell growth, intracellular arsenic, and protein aggregation during arsenate exposure. Overexpression of PHO86 resulted in higher cellular arsenic levels but no additional effect on protein aggregation, indicating that these cells efficiently protect their intracellular environment. VBA3 overexpression caused resistance despite higher intracellular arsenic and protein aggregation levels. Overexpression of UGP1 led to lower intracellular arsenic and protein aggregation levels while TUL1 overexpression had no impact on intracellular arsenic or protein aggregation levels. Thus, the identified genes appear to confer arsenic resistance through distinct mechanisms but the molecular details remain to be elucidated.
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| 33. |
- Jacobson, Therese, et al.
(författare)
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Arsenite interferes with protein folding and triggers formation of protein aggregates in yeast.
- 2012
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Ingår i: Journal of cell science. - : The Company of Biologists. - 1477-9137 .- 0021-9533. ; 125:21, s. 5073-83
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Tidskriftsartikel (refereegranskat)abstract
- Several metals and metalloids profoundly affect biological systems, but their impact on the proteome and mechanisms of toxicity are not fully understood. Here, we demonstrate that arsenite causes protein aggregation in Saccharomyces cerevisiae. Various molecular chaperones were found to be associated with arsenite-induced aggregates indicating that this metalloid promotes protein misfolding. Using in vivo and in vitro assays, we show that proteins in the process of synthesis/folding are particularly sensitive to arsenite-induced aggregation, that arsenite interferes with protein folding by acting on unfolded polypeptides, and that arsenite directly inhibits chaperone activity. Thus, folding inhibition contributes to arsenite toxicity in two ways: by aggregate formation and by chaperone inhibition. Importantly, arsenite-induced protein aggregates can act as seeds committing other, labile proteins to misfold and aggregate. Our findings describe a novel mechanism of toxicity that may explain the suggested role of this metalloid in the etiology and pathogenesis of protein folding disorders associated with arsenic poisoning.
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| 34. |
- Jacobson, Therese, et al.
(författare)
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Cadmium Causes Misfolding and Aggregation of Cytosolic Proteins in Yeast.
- 2017
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Ingår i: Molecular and Cellular Biology. - 1098-5549. ; 37:17
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Tidskriftsartikel (refereegranskat)abstract
- Cadmium is a highly poisonous metal and is classified as a human carcinogen. While its toxicity is undisputed, the underlying in vivo molecular mechanisms are not fully understood. Here, we demonstrate that cadmium induces aggregation of cytosolic proteins in living Saccharomyces cerevisiae cells. Cadmium primarily targets proteins in the process of synthesis or folding, probably by interacting with exposed thiol groups in not-yet-folded proteins. On the basis of in vitro and in vivo data, we show that cadmium-aggregated proteins form seeds that increase the misfolding of other proteins. Cells that cannot efficiently protect the proteome from cadmium-induced aggregation or clear the cytosol of protein aggregates are sensitized to cadmium. Thus, protein aggregation may contribute to cadmium toxicity. This is the first report on how cadmium causes misfolding and aggregation of cytosolic proteins in vivo The proposed mechanism might explain not only the molecular basis of the toxic effects of cadmium but also the suggested role of this poisonous metal in the pathogenesis of certain protein-folding disorders.
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| 35. |
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| 36. |
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| 37. |
- Karlgren, Sara, 1975, et al.
(författare)
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Identification of residues controlling transport through the yeast aquaglyceroporin Fps1 using a genetic screen
- 2004
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Ingår i: European journal of biochemistry. - : Wiley. - 0014-2956. ; 271:4, s. 771-779
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Tidskriftsartikel (refereegranskat)abstract
- Aquaporins and aquaglyceroporins mediate the transport of water and solutes across biological membranes. Saccharomyces cerevisiae Fps1 is an aquaglyceroporin that mediates controlled glycerol export during osmoregulation. The transport function of Fps1 is rapidly regulated by osmotic changes in an apparently unique way and distinct regions within the long N- and C-terminal extensions are needed for this regulation. In order to learn more about the mechanisms that control Fps1 we have set up a genetic screen for hyperactive Fps1 and isolated mutations in 14 distinct residues, all facing the inside of the cell. Five of the residues lie within the previously characterized N-terminal regulatory domain and two mutations are located within the approach to the first transmembrane domain. Three mutations cause truncation of the C-terminus, confirming previous studies on the importance of this region for channel control. Furthermore, the novel mutations identify two conserved residues in the channel-forming B-loop as critical for channel control. Structural modelling-based rationalization of the observed mutations supports the notion that the N-terminal regulatory domain and the B-loop could interact in channel control. Our findings provide a framework for further genetic and structural analysis to better understand the mechanism that controls Fps1 function by osmotic changes
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| 38. |
- Kejžar, Anja, et al.
(författare)
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HwHog1 kinase activity is crucial for survival of Hortaea werneckii in extremely hyperosmolar environments.
- 2015
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Ingår i: Fungal genetics and biology : FG & B. - : Elsevier BV. - 1096-0937 .- 1087-1845. ; 74, s. 45-58
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Tidskriftsartikel (refereegranskat)abstract
- Although suggested, the involvement of the HOG pathway in adaptation processes in extremely halotolerant fungus Hortaea werneckii has never been specifically demonstrated. Here, we show that the H. werneckii HOG pathway is very robust, and that it includes two functionally redundant MAPK homologues, HwHog1A and HwHog1B, that show osmolyte-type-dependent phosphorylation. Inhibition of HwHog1 kinase activity with the ATP analogue BPTIP restricts H. werneckii colony growth at 3.0M NaCl, KCl and sorbitol, most likely due to restricted cell division. On the other hand, HwHog1-regulated transcription of a selected group of genes (HwSTL1, HwGUT2, HwOPI3, HwGDH1, HwUGP1, HwGPD1) is an osmolyte-specific process that is important for induction of gene transcription with high NaCl, for regulation of specific genes with high sorbitol, and has no role in KCl stressed cells. Survival of H. werneckii at moderate NaCl and KCl concentrations is not dependent on HwHog1 activity or the calcineurin pathway, and thus alternative mechanisms must exist. The HOG pathway described here is vital for the extreme osmotolerance of H. werneckii, and its regulation shows important differences from the homologue pathways characterised in other mesophilic and halotolerant fungi.
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| 39. |
- Kristiansson, Erik, 1978, et al.
(författare)
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Evolutionary Forces Act on Promoter Length: Identification of Enriched Cis-Regulatory Elements
- 2009
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Ingår i: Molecular Biology and Evolution. ; 26:6, s. 1299-1307
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Tidskriftsartikel (refereegranskat)abstract
- Transcription factors govern gene expression by binding to short DNA sequences called cis-regulatory elements. These sequences are typically located in promoters, which are regions of variable length upstream of the open reading frames of genes. Here, we report that promoter length and gene function are related in yeast, fungi, and plants. In particular, the promoters for stress-responsive genes are in general longer than those of other genes. Essential genes have, on the other hand, relatively short promoters. We utilize these findings in a novel method for identifying relevant cis-regulatory elements in a set of coexpressed genes. The method is shown to generate more accurate results and fewer false positives compared with other common procedures. Our results suggest that genes with complex transcriptional regulation tend to have longer promoters than genes responding to few signals. This phenomenon is present in all investigated species, indicating that evolution adjust promoter length according to gene function. Identification of cis-regulatory elements in Saccharomyces cerevisiae can be done with the web service located at http://enricher.zool.gu.se.
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| 40. |
- Kumar, Nallani Vijay, et al.
(författare)
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Arsenic Directly Binds to and Activates the Yeast AP-1-Like Transcription Factor Yap8.
- 2016
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Ingår i: Molecular and cellular biology. - 1098-5549. ; 36:6, s. 913-22
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Tidskriftsartikel (refereegranskat)abstract
- The AP-1-like transcription factor Yap8 is critical for arsenic tolerance in the yeast Saccharomyces cerevisiae. However, the mechanism by which Yap8 senses the presence of arsenic and activates transcription of detoxification genes is unknown. Here we demonstrate that Yap8 directly binds to trivalent arsenite [As(III)] in vitro and in vivo and that approximately one As(III) molecule is bound per molecule of Yap8. As(III) is coordinated by three sulfur atoms in purified Yap8, and our genetic and biochemical data identify the cysteine residues that form the binding site as Cys132, Cys137, and Cys274. As(III) binding by Yap8 does not require an additional yeast protein, and Yap8 is regulated neither at the level of localization nor at the level of DNA binding. Instead, our data are consistent with a model in which a DNA-bound form of Yap8 acts directly as an As(III) sensor. Binding of As(III) to Yap8 triggers a conformational change that in turn brings about a transcriptional response. Thus, As(III) binding to Yap8 acts as a molecular switch that converts inactive Yap8 into an active transcriptional regulator. This is the first report to demonstrate how a eukaryotic protein couples arsenic sensing to transcriptional activation.
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| 41. |
- Ljungdahl, Thomas, 1974, et al.
(författare)
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Positional Scanning Peptide Libraries for Kinase Substrate Specificity Determinations: Straightforward and Reproducible Synthesis Using Pentafluorophenyl Esters.
- 2010
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Ingår i: Journal of combinatorial chemistry. - : American Chemical Society (ACS). - 1520-4774 .- 1520-4766. ; 12:5, s. 733-742
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Tidskriftsartikel (refereegranskat)abstract
- An efficient method to synthesize positional scanning synthetic combinatorial libraries (PS-SCLs) for studying the specificity of protein kinases is presented. Isokinetic ratios for pentafluorophenyl esters were determined iteratively using a new approach incorporating high performance liquid chromatography (HPLC) quantification and statistical experimental design. In the development process a large amount of work was put in to find efficient ways of screening for new isokinetic mixtures and to optimize the process of PS-SCL synthesis. The newly developed methods for the screening of isokinetic mixtures could be used for the screening of other interesting mixtures, but more importantly, the isokinetic ratios determined for the preactivated pentafluorophenyl esters were incorporated into a new efficient protocol. This straightforward protocol allows for a convenient synthesis of high quality PS-SCLs regardless of previous experience in solid phase synthesis.
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| 42. |
- Lorentzon, Emma, 1995, et al.
(författare)
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Effects of the toxic metals arsenite and cadmium on α-synuclein aggregation in vitro and in cells
- 2021
-
Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 22:21
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to heavy metals, including arsenic and cadmium, is associated with neurodegen-erative disorders such as Parkinson’s disease. However, the mechanistic details of how these metals contribute to pathogenesis are not well understood. To search for underlying mechanisms involving α-synuclein, the protein that forms amyloids in Parkinson’s disease, we here assessed the effects of arsenic and cadmium on α-synuclein amyloid formation in vitro and in Saccharomyces cerevisiae (budding yeast) cells. Atomic force microscopy experiments with acetylated human α-synuclein demonstrated that amyloid fibers formed in the presence of the metals have a different fiber pitch compared to those formed without metals. Both metal ions become incorporated into the amyloid fibers, and cadmium also accelerated the nucleation step in the amyloid formation process, likely via binding to intermediate species. Fluorescence microscopy analyses of yeast cells expressing fluorescently tagged α-synuclein demonstrated that arsenic and cadmium affected the distribution of α-synuclein aggregates within the cells, reduced aggregate clearance, and aggravated α-synuclein toxicity. Taken together, our in vitro data demonstrate that interactions between these two metals and α-synuclein modulate the resulting amyloid fiber structures, which, in turn, might relate to the observed effects in the yeast cells. Whilst our study advances our understanding of how these metals affect α-synuclein biophysics, further in vitro characterization as well as human cell studies are desired to fully appreciate their role in the progression of Parkinson’s disease.
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| 43. |
- Maciaszczyk-Dziubinska, Ewa, et al.
(författare)
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The ancillary N-terminal region of the yeast AP-1 transcription factor Yap8 contributes to its DNA binding specificity.
- 2020
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Ingår i: Nucleic acids research. - 1362-4962. ; 48:10, s. 5426-5441
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Tidskriftsartikel (refereegranskat)abstract
- Activator protein 1 (AP-1) is one of the largest families of basic leucine zipper (bZIP) transcription factors in eukaryotic cells. How AP-1 proteins achieve target DNA binding specificity remains elusive. In Saccharomyces cerevisiae, the AP-1-like protein (Yap) family comprises eight members (Yap1 to Yap8) that display distinct genomic target sites despite high sequence homology of their DNA binding bZIP domains. In contrast to the other members of the Yap family, which preferentially bind to short (7-8 bp) DNA motifs, Yap8 binds to an unusually long DNA motif (13 bp). It has been unclear what determines this unique specificity of Yap8. In this work, we use molecular and biochemical analyses combined with computer-based structural design and molecular dynamics simulations of Yap8-DNA interactions to better understand the structural basis of DNA binding specificity determinants. We identify specific residues in the N-terminal tail preceding the basic region, which define stable association of Yap8 with its target promoter. We propose that the N-terminal tail directly interacts with DNA and stabilizes Yap8 binding to the 13 bp motif. Thus, beside the core basic region, the adjacent N-terminal region contributes to alternative DNA binding selectivity within the AP-1 family.
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| 44. |
- Mandal, Goutam, et al.
(författare)
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Modulation of Leishmania major aquaglyceroporin activity by a mitogen-activated protein kinase.
- 2012
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Ingår i: Molecular microbiology. - : Wiley. - 1365-2958 .- 0950-382X. ; 85:6, s. 1204-1218
-
Tidskriftsartikel (refereegranskat)abstract
- Leishmania major aquaglyceroporin (LmjAQP1) adventitiously facilitates the uptake of antimonite [Sb(III)], an active form of Pentostam® or Glucantime®, which are the first line of defence against all forms of leishmaniasis. The present paper shows that LmjAQP1 activity is modulated by the mitogen-activated protein kinase, LmjMPK2. Leishmania parasites coexpressing LmjAQP1 and LmjMPK2 show increased Sb(III) uptake and increased Sb(III) sensitivity. When subjected to a hypo-osmotic stress, these cells show faster volume recovery than cells expressing LmjAQP1 alone. LmjAQP1 is phosphorylated in vivo at Thr-197 and this phosphorylation requires LmjMPK2 activity. Lys-42 of LmjMPK2 is critical for its kinase activity. Cells expressing altered T197A LmjAQP1 or K42A LmjMPK2 showed decreased Sb(III) influx and a slower volume recovery than cells expressing wild-type proteins. Phosphorylation of LmjAQP1 led to a decrease in its turnover rate affecting LmjAQP1 activity. Although LmjAQP1 is localized to the flagellum of promastigotes, upon phosphorylation, it is relocalized to the entire surface of the parasite. Leishmania mexicana promastigotes with an MPK2 deletion showed reduced Sb(III) uptake and slower volume recovery than wild-type cells. This is the first report where a parasite aquaglyceroporin activity is post-translationally modulated by a mitogen-activated protein kinase.
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| 45. |
- Migdal, Iwona, et al.
(författare)
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Mitogen-activated protein kinase Hog1 mediates adaptation to G1 checkpoint arrest during arsenite and hyperosmotic stress
- 2008
-
Ingår i: Eukaryotic Cell. ; 7:8, s. 1309-1317
-
Tidskriftsartikel (refereegranskat)abstract
- Cells slow down cell cycle progression in order to adapt to unfavorable stress conditions. Yeast (Saccharomyces cerevisiae) responds to osmotic stress by triggering G(1) and G(2) checkpoint delays that are dependent on the mitogen-activated protein kinase (MAPK) Hog1. The high-osmolarity glycerol (HOG) pathway is also activated by arsenite, and the hog1Delta mutant is highly sensitive to arsenite, partly due to increased arsenite influx into hog1Delta cells. Yeast cell cycle regulation in response to arsenite and the role of Hog1 in this process have not yet been analyzed. Here, we found that long-term exposure to arsenite led to transient G(1) and G(2) delays in wild-type cells, whereas cells that lack the HOG1 gene or are defective in Hog1 kinase activity displayed persistent G(1) cell cycle arrest. Elevated levels of intracellular arsenite and "cross talk" between the HOG and pheromone response pathways, observed in arsenite-treated hog1Delta cells, prolonged the G(1) delay but did not cause a persistent G(1) arrest. In contrast, deletion of the SIC1 gene encoding a cyclin-dependent kinase inhibitor fully suppressed the observed block of G(1) exit in hog1Delta cells. Moreover, the Sic1 protein was stabilized in arsenite-treated hog1Delta cells. Interestingly, Sic1-dependent persistent G(1) arrest was also observed in hog1Delta cells during hyperosmotic stress. Taken together, our data point to an important role of the Hog1 kinase in adaptation to stress-induced G(1) cell cycle arrest.
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| 46. |
- Nielsen, Jens B, 1962, et al.
(författare)
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Professor Stefan Hohmann (08.09.1956-02.07.2021)
- 2022
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Ingår i: FEMS Yeast Research. - : Oxford University Press (OUP). - 1567-1356 .- 1567-1364. ; 22:1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 47. |
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| 48. |
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| 49. |
- Panagaki, Dimitra, et al.
(författare)
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Nuclear envelope budding is a response to cellular stress.
- 2021
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 118:30
-
Tidskriftsartikel (refereegranskat)abstract
- Nuclear envelope budding (NEB) is a recently discovered alternative pathway for nucleocytoplasmic communication distinct from the movement of material through the nuclear pore complex. Through quantitative electron microscopy and tomography, we demonstrate how NEB is evolutionarily conserved from early protists to human cells. In the yeast Saccharomyces cerevisiae, NEB events occur with higher frequency during heat shock, upon exposure to arsenite or hydrogen peroxide, and when the proteasome is inhibited. Yeast cells treated with azetidine-2-carboxylic acid, a proline analog that induces protein misfolding, display the most dramatic increase in NEB, suggesting a causal link to protein quality control. This link was further supported by both localization of ubiquitin and Hsp104 to protein aggregates and NEB events, and the evolution of these structures during heat shock. We hypothesize that NEB is part of normal cellular physiology in a vast range of species and that in S. cerevisiae NEB comprises a stress response aiding the transport of protein aggregates across the nuclear envelope.
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| 50. |
- Persson, Karl, 1988, et al.
(författare)
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Adaptation of the yeast gene knockout collection is near-perfectly predicted by fitness and diminishing return epistasis.
- 2022
-
Ingår i: G3 (Bethesda, Md.). - : Oxford University Press (OUP). - 2160-1836. ; 12:11
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Tidskriftsartikel (refereegranskat)abstract
- Adaptive evolution of clonally dividing cells and microbes is the ultimate cause of cancer and infectious diseases. The possibility of constraining the adaptation of cell populations, by inhibiting proteins enhancing the evolvability, has therefore attracted interest. However, our current understanding of how genes influence adaptation kinetics is limited, partly because accurately measuring adaptation for many cell populations is challenging. We used a high-throughput adaptive laboratory evolution platform to track the adaptation of >18,000 cell populations corresponding to single-gene deletion strains in the haploid yeast deletion collection. We report that the preadaptation fitness of gene knockouts near-perfectly (R2= 0.91) predicts their adaptation to arsenic, leaving at the most a marginal role for dedicated evolvability gene functions. We tracked the adaptation of another >23,000 gene knockout populations to a diverse range of selection pressures and generalized the almost perfect (R2=0.72-0.98) capacity of preadaptation fitness to predict adaptation. We also reconstructed mutations in FPS1, ASK10, and ARR3, which together account for almost all arsenic adaptation in wild-type cells, in gene deletions covering a broad fitness range and show that the predictability of arsenic adaptation can be understood as a by global epistasis, where excluding arsenic is more beneficial to arsenic unfit cells. The paucity of genes with a meaningful evolvability effect on adaptation diminishes the prospects of developing adjuvant drugs aiming to slow antimicrobial and chemotherapy resistance.
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