| 1. |
- Ahmadpour, Doryaneh, 1973, et al.
(författare)
-
The mitogen-activated protein kinase Slt2 modulates arsenite transport through the aquaglyceroporin Fps1
- 2016
-
Ingår i: FEBS Letters. - : Wiley. - 0014-5793 .- 1873-3468. ; 590:20, s. 3649-3659
-
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.
|
|
| 2. |
- Dinér, Peter, 1976, et al.
(författare)
-
Design, synthesis, and characterization of a highly effective Hog1 inhibitor: a powerful tool for analyzing MAP kinase signaling in yeast.
- 2011
-
Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 6:5
-
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.
|
|
| 3. |
|
|
| 4. |
- Gjuvsland, Arne B, et al.
(författare)
-
Disentangling genetic and epigenetic determinants of ultrafast adaptation.
- 2016
-
Ingår i: Molecular systems biology. - : EMBO. - 1744-4292. ; 12:12
-
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.
|
|
| 5. |
- Ilina, Yulia, et al.
(författare)
-
Characterization of the DNA-binding motif of the arsenic-responsive transcription factor Yap8p.
- 2008
-
Ingår i: The Biochemical journal. - 1470-8728. ; 415:3, s. 467-75
-
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.
|
|
| 6. |
- Maciaszczyk-Dziubinska, Ewa, et al.
(författare)
-
The ancillary N-terminal region of the yeast AP-1 transcription factor Yap8 contributes to its DNA binding specificity.
- 2020
-
Ingår i: Nucleic acids research. - 1362-4962. ; 48:10, s. 5426-5441
-
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.
|
|
| 7. |
- Migdal, Iwona, et al.
(författare)
-
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.
|
|
| 8. |
- Romero, Antonia, et al.
(författare)
-
Etp1 confers arsenite resistance by affecting ACR3 expression.
- 2022
-
Ingår i: FEMS yeast research. - : Oxford University Press (OUP). - 1567-1364. ; 22:1
-
Tidskriftsartikel (refereegranskat)abstract
- In a high-throughput yeast two-hybrid screen of predicted coiled-coil motif interactions in the Saccharomyces cerevisiae proteome, the protein Etp1 was found to interact with the yeast AP-1-like transcription factors Yap8, Yap1 and Yap6. Yap8 plays a crucial role during arsenic stress since it regulates expression of the resistance genes ACR2 and ACR3. The function of Etp1 is not well understood but the protein has been implicated in transcription and protein turnover during ethanol stress, and the etp1∆ mutant is sensitive to ethanol. In this current study, we investigated whether Etp1 is implicated in Yap8-dependent functions. We show that Etp1 is required for optimal growth in the presence of trivalent arsenite and for optimal expression of the arsenite export protein encoded by ACR3. Since Yap8 is the only known transcription factor that regulates ACR3 expression, we investigated whether Etp1 regulates Yap8. Yap8 ubiquitination, stability, nuclear localization and ACR3 promoter association were unaffected in etp1∆ cells, indicating that Etp1 affects ACR3 expression independently of Yap8. Thus, Etp1 impacts gene expression under arsenic and other stress conditions but the mechanistic details remain to be elucidated.
|
|
| 9. |
- Tamás, Markus J., 1970, et al.
(författare)
-
Mechanisms of toxic metal tolerance in yeast
- 2005
-
Ingår i: Molecular Biology of Metal Homeostasis and Detoxification; Eds Tamás M.J and Martinoia E.. - Berlin, Heidelberg : Springer Berlin Heidelberg. ; , s. 395-454
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
- Thorsen, Michael, 1974, et al.
(författare)
-
The MAPK Hog1p modulates Fps1p-dependent arsenite uptake and tolerance in yeast.
- 2006
-
Ingår i: Molecular biology of the cell. - 1059-1524 .- 1939-4586. ; 17:10, s. 4400-10
-
Tidskriftsartikel (refereegranskat)abstract
- Arsenic is widely distributed in nature and all organisms possess regulatory mechanisms to evade toxicity and acquire tolerance. Yet, little is known about arsenic sensing and signaling mechanisms or about their impact on tolerance and detoxification systems. Here, we describe a novel role of the S. cerevisiae mitogen-activated protein kinase Hog1p in protecting cells during exposure to arsenite and the related metalloid antimonite. Cells impaired in Hog1p function are metalloid hypersensitive, whereas cells with elevated Hog1p activity display improved tolerance. Hog1p is phosphorylated in response to arsenite and this phosphorylation requires Ssk1p and Pbs2p. Arsenite-activated Hog1p remains primarily cytoplasmic and does not mediate a major transcriptional response. Instead, hog1delta sensitivity is accompanied by elevated cellular arsenic levels and we demonstrate that increased arsenite influx is dependent on the aquaglyceroporin Fps1p. Fps1p is phosphorylated on threonine 231 in vivo and this phosphorylation critically affects Fps1p activity. Moreover, Hog1p is shown to affect Fps1p phosphorylation. Our data are the first to demonstrate Hog1p activation by metalloids and provides a mechanism by which this kinase contributes to tolerance acquisition. Understanding how arsenite/antimonite uptake and toxicity is modulated may prove of value for their use in medical therapy.
|
|
| 13. |
- Veide Vilg, Jenny, 1973, et al.
(författare)
-
Arsenic resistance in Kluyveromyces lactis
- 2009
-
Ingår i: International Conference on Yeast Genetics and Molecular Biology, Manchester, UK.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 14. |
- Veide Vilg, Jenny, 1973, et al.
(författare)
-
Arsenic resistance in Kluyveromyces lactis
- 2010
-
Ingår i: Annual Spring Meeting of the Swedish Microbiology Societies, Gothenburg, Sweden.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 15. |
- Veide Vilg, Jenny, 1973, et al.
(författare)
-
Elucidating the response of Kluyveromyces lactis to arsenite and peroxide stress and the role of the transcription factor KlYap8.
- 2014
-
Ingår i: Biochimica et biophysica acta. - : Elsevier BV. - 0006-3002. ; 1839:11, s. 1295-1306
-
Tidskriftsartikel (refereegranskat)abstract
- All organisms need to sense and respond to a range of stress conditions. In this study, we used transcriptional profiling to identify genes and cellular processes that are responsive during arsenite and tert-butyl hydroperoxide exposure in Kluyveromyces lactis. Many arsenite-responsive genes encode proteins involved in redox processes, protein folding and stabilization, and transmembrane transport. The majority of peroxide-responsive genes encode functions related to transcription, translation, redox processes, metabolism and transport. A substantial number of these stress-regulated genes contain binding motifs for the AP-1 like transcription factors KlYap1 and KlYap8. We demonstrate that KlYap8 binds to and regulates gene expression through a 13 base-pair promoter motif, and that KlYap8 provides protection against arsenite, antimonite, cadmium and peroxide toxicity. Direct transport assays show that Klyap8Δ cells accumulate more arsenic and cadmium than wild type cells and that the Klyap8Δ mutant is defective in arsenic and cadmium export. KlYap8 regulates gene expression in response to both arsenite and peroxide, and might cooperate with KlYap1 in regulation of specific gene targets. Comparison of KlYap8 with its Saccharomyces cerevisiae orthologue ScYap8 indicates that KlYap8 senses and responds to multiple stress signals whereas ScYap8 is only involved in the response to arsenite and antimonite. Thus, our data suggest that functional specialization of ScYap8 has occurred after the whole genome duplication event. This is the first genome-wide stress response analysis in K. lactis and the first demonstration of KlYap8 function.
|
|
| 16. |
- Vesikari, Timo, et al.
(författare)
-
Meningococcal Serogroup B Bivalent rLP2086 Vaccine Elicits Broad and Robust Serum Bactericidal Responses in Healthy Adolescents.
- 2016
-
Ingår i: Journal of the Pediatric Infectious Diseases Society. - : Oxford University Press (OUP). - 2048-7207 .- 2048-7193.
-
Tidskriftsartikel (refereegranskat)abstract
- Neisseria meningitidis serogroup B (MnB) is a leading cause of invasive meningococcal disease in adolescents and young adults. A recombinant factor H binding protein (fHBP) vaccine (Trumenba(®); bivalent rLP2086) was recently approved in the United States in individuals aged 10-25 years. Immunogenicity and safety of 2- or 3-dose schedules of bivalent rLP2086 were assessed in adolescents.
|
|
| 17. |
- Wysocki, Robert, et al.
(författare)
-
How Saccharomyces cerevisiae copes with toxic metals and metalloids.
- 2010
-
Ingår i: FEMS microbiology reviews. - : Oxford University Press (OUP). - 1574-6976. ; 34:6, s. 925-51
-
Forskningsöversikt (refereegranskat)abstract
- Toxic metals and metalloids are widespread in nature and can locally reach fairly high concentrations. To ensure cellular protection and survival in such environments, all organisms possess systems to evade toxicity and acquire tolerance. This review provides an overview of the molecular mechanisms that contribute to metal toxicity, detoxification and tolerance acquisition in budding yeast Saccharomyces cerevisiae. We mainly focus on the metals/metalloids arsenic, cadmium, antimony, mercury, chromium and selenium, and emphasize recent findings on sensing and signalling mechanisms and on the regulation of tolerance and detoxification systems that safeguard cellular and genetic integrity.
|
|
| 18. |
- Wysocki, Robert, et al.
(författare)
-
Mechanisms of genotoxicity and proteotoxicity induced by the metalloids arsenic and antimony.
- 2023
-
Ingår i: Cellular and molecular life sciences : CMLS. - 1420-9071. ; 80:11
-
Forskningsöversikt (refereegranskat)abstract
- Arsenic and antimony are metalloids with profound effects on biological systems and human health. Both elements are toxic to cells and organisms, and exposure is associated with several pathological conditions including cancer and neurodegenerative disorders. At the same time, arsenic- and antimony-containing compounds are used in the treatment of multiple diseases. Although these metalloids can both cause and cure disease, their modes of molecular action are incompletely understood. The past decades have seen major advances in our understanding of arsenic and antimony toxicity, emphasizing genotoxicity and proteotoxicity as key contributors to pathogenesis. In this review, we highlight mechanisms by which arsenic and antimony cause toxicity, focusing on their genotoxic and proteotoxic effects. The mechanisms used by cells to maintain proteostasis during metalloid exposure are also described. Furthermore, we address how metalloid-induced proteotoxicity may promote neurodegenerative disease and how genotoxicity and proteotoxicity may be interrelated and together contribute to proteinopathies. A deeper understanding of cellular toxicity and response mechanisms and their links to pathogenesis may promote the development of strategies for both disease prevention and treatment.
|
|
| 19. |
- Wysocki, Robert, et al.
(författare)
-
Metalloid tolerance based on phytochelatins is not functionally equivalent to the arsenite transporter Acr3p.
- 2003
-
Ingår i: Biochemical and biophysical research communications. - 0006-291X. ; 304:2, s. 293-300
-
Tidskriftsartikel (refereegranskat)abstract
- Active transport of metalloids by Acr3p and Ycf1p in Saccharomyces cerevisiae and chelation by phytochelatins in Schizosaccharomyces pombe, nematodes, and plants represent distinct strategies of metalloid detoxification. In this report, we present results of functional comparison of both resistance mechanisms. The S. pombe and wheat phytochelatin synthase (PCS) genes, when expressed in S. cerevisiae, mediate only modest resistance to arsenite and thus cannot functionally compensate for Acr3p. On the other hand, we show for the first time that phytochelatins also contribute to antimony tolerance as PCS fully complement antimonite sensitivity of ycf1Delta mutant. Remarkably, heterologous expression of PCS sensitizes S. cerevisiae to arsenate, while ACR3 confers much higher arsenic resistance in pcsDelta than in wild-type S. pombe. The analysis of PCS and ACR3 homologues distribution in various organisms and our experimental data suggest that separation of ACR3 and PCS genes may lead to the optimal tolerance status of the cell.
|
|
| 20. |
|
|
| 21. |
- Wysocki, Robert, et al.
(författare)
-
Transcriptional Activation of Metalloid Tolerance Genes in Saccharomyces cerevisiae Requires the AP-1like Proteins Yap1p and Yap8p
- 2004
-
Ingår i: Molecular Biology of the Cell. ; 15:5, s. 2049-2060
-
Tidskriftsartikel (refereegranskat)abstract
- All organisms are equipped with systems for detoxification of the metalloids arsenic and antimony. Here, we show that two parallel pathways involving the AP-1like proteins Yap1p and Yap8p are required for acquisition of metalloid tolerance in the budding yeast S. cerevisiae. Yap8p is demonstrated to reside in the nucleus where it mediates enhanced expression of the arsenic detoxification genes ACR2 and ACR3. Using chromatin immunoprecipitation assays, we show that Yap8p is associated with the ACR3 promoter in untreated as well as arsenic-exposed cells. Like for Yap1p, specific cysteine residues are critical for Yap8p function. We further show that metalloid exposure triggers nuclear accumulation of Yap1p and stimulates expression of antioxidant genes. Yap1p mutants that are unable to accumulate in the nucleus during H2O2 treatment showed nearly normal nuclear retention in response to metalloid exposure. Thus, our data are the first to demonstrate that Yap1p is being regulated by metalloid stress and to indicate that this activation of Yap1p operates in a manner distinct from stress caused by chemical oxidants. We conclude that Yap1p and Yap8p mediate tolerance by controlling separate subsets of detoxification genes and propose that the two AP-1like proteins respond to metalloids through distinct mechanisms.
|
|
