--- _id: '803' abstract: - lang: eng text: Eukaryotic cells store their chromosomes in a single nucleus. This is important to maintain genomic integrity, as chromosomes packaged into separate nuclei (micronuclei) are prone to massive DNA damage. During mitosis, higher eukaryotes disassemble their nucleus and release individualized chromosomes for segregation. How numerous chromosomes subsequently reform a single nucleus has remained unclear. Using image-based screening of human cells, we identified barrier-to-autointegration factor (BAF) as a key factor guiding membranes to form a single nucleus. Unexpectedly, nuclear assembly does not require BAF?s association with inner nuclear membrane proteins but instead relies on BAF?s ability to bridge distant DNA sites. Live-cell imaging and in vitro reconstitution showed that BAF enriches around the mitotic chromosome ensemble to induce a densely cross-bridged chromatin layer that is mechanically stiff and limits membranes to the surface. Our study reveals that BAF-mediated changes in chromosome mechanics underlie nuclear assembly with broad implications for proper genome function. acknowledged_ssus: - _id: Bio article_processing_charge: No author: - first_name: Matthias full_name: Samwer, Matthias last_name: Samwer - first_name: Maximilian full_name: Schneider, Maximilian last_name: Schneider - first_name: Rudolf full_name: Hoefler, Rudolf last_name: Hoefler - first_name: Philipp S full_name: Schmalhorst, Philipp S id: 309D50DA-F248-11E8-B48F-1D18A9856A87 last_name: Schmalhorst orcid: 0000-0002-5795-0133 - first_name: Julian full_name: Jude, Julian last_name: Jude - first_name: Johannes full_name: Zuber, Johannes last_name: Zuber - first_name: Daniel full_name: Gerlic, Daniel last_name: Gerlic citation: ama: Samwer M, Schneider M, Hoefler R, et al. DNA cross-bridging shapes a single nucleus from a set of mitotic chromosomes. Cell. 2017;170(5):956-972. doi:10.1016/j.cell.2017.07.038 apa: Samwer, M., Schneider, M., Hoefler, R., Schmalhorst, P. S., Jude, J., Zuber, J., & Gerlic, D. (2017). DNA cross-bridging shapes a single nucleus from a set of mitotic chromosomes. Cell. Cell Press. https://doi.org/10.1016/j.cell.2017.07.038 chicago: Samwer, Matthias, Maximilian Schneider, Rudolf Hoefler, Philipp S Schmalhorst, Julian Jude, Johannes Zuber, and Daniel Gerlic. “DNA Cross-Bridging Shapes a Single Nucleus from a Set of Mitotic Chromosomes.” Cell. Cell Press, 2017. https://doi.org/10.1016/j.cell.2017.07.038. ieee: M. Samwer et al., “DNA cross-bridging shapes a single nucleus from a set of mitotic chromosomes,” Cell, vol. 170, no. 5. Cell Press, pp. 956–972, 2017. ista: Samwer M, Schneider M, Hoefler R, Schmalhorst PS, Jude J, Zuber J, Gerlic D. 2017. DNA cross-bridging shapes a single nucleus from a set of mitotic chromosomes. Cell. 170(5), 956–972. mla: Samwer, Matthias, et al. “DNA Cross-Bridging Shapes a Single Nucleus from a Set of Mitotic Chromosomes.” Cell, vol. 170, no. 5, Cell Press, 2017, pp. 956–72, doi:10.1016/j.cell.2017.07.038. short: M. Samwer, M. Schneider, R. Hoefler, P.S. Schmalhorst, J. Jude, J. Zuber, D. Gerlic, Cell 170 (2017) 956–972. date_created: 2018-12-11T11:48:35Z date_published: 2017-08-24T00:00:00Z date_updated: 2023-09-27T10:59:14Z day: '24' ddc: - '570' department: - _id: CaHe doi: 10.1016/j.cell.2017.07.038 external_id: isi: - '000408372400014' file: - access_level: open_access checksum: 64897b0c5373f22273f598e4672c60ff content_type: application/pdf creator: dernst date_created: 2019-01-18T13:45:40Z date_updated: 2020-07-14T12:48:08Z file_id: '5852' file_name: 2017_Cell_Samwer.pdf file_size: 17666637 relation: main_file file_date_updated: 2020-07-14T12:48:08Z has_accepted_license: '1' intvolume: ' 170' isi: 1 issue: '5' language: - iso: eng license: https://creativecommons.org/licenses/by-nc-nd/4.0/ month: '08' oa: 1 oa_version: Published Version page: 956 - 972 publication: Cell publication_identifier: issn: - '00928674' publication_status: published publisher: Cell Press publist_id: '6848' quality_controlled: '1' scopus_import: '1' status: public title: DNA cross-bridging shapes a single nucleus from a set of mitotic chromosomes tmp: image: /images/cc_by_nc_nd.png legal_code_url: https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode name: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) short: CC BY-NC-ND (4.0) type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 170 year: '2017' ... --- _id: '804' abstract: - lang: eng text: Polysaccharides (carbohydrates) are key regulators of a large number of cell biological processes. However, precise biochemical or genetic manipulation of these often complex structures is laborious and hampers experimental structure–function studies. Molecular Dynamics (MD) simulations provide a valuable alternative tool to generate and test hypotheses on saccharide function. Yet, currently used MD force fields often overestimate the aggregation propensity of polysaccharides, affecting the usability of those simulations. Here we tested MARTINI, a popular coarse-grained (CG) force field for biological macromolecules, for its ability to accurately represent molecular forces between saccharides. To this end, we calculated a thermodynamic solution property, the second virial coefficient of the osmotic pressure (B22). Comparison with light scattering experiments revealed a nonphysical aggregation of a prototypical polysaccharide in MARTINI, pointing at an imbalance of the nonbonded solute–solute, solute–water, and water–water interactions. This finding also applies to smaller oligosaccharides which were all found to aggregate in simulations even at moderate concentrations, well below their solubility limit. Finally, we explored the influence of the Lennard-Jones (LJ) interaction between saccharide molecules and propose a simple scaling of the LJ interaction strength that makes MARTINI more reliable for the simulation of saccharides. acknowledged_ssus: - _id: ScienComp acknowledgement: P.S.S. was supported by research fellowship 2811/1-1 from the German Research Foundation (DFG), and M.S. was supported by EMBO Long Term Fellowship ALTF 187-2013 and Grant GC65-32 from the Interdisciplinary Centre for Mathematical and Computational Modelling (ICM), University of Warsaw, Poland. The authors thank Antje Potthast, Marek Cieplak, Tomasz Włodarski, and Damien Thompson for fruitful discussions and the IST Austria Scientific Computing Facility for support. article_processing_charge: No author: - first_name: Philipp S full_name: Schmalhorst, Philipp S id: 309D50DA-F248-11E8-B48F-1D18A9856A87 last_name: Schmalhorst orcid: 0000-0002-5795-0133 - first_name: Felix full_name: Deluweit, Felix last_name: Deluweit - first_name: Roger full_name: Scherrers, Roger last_name: Scherrers - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 - first_name: Mateusz K full_name: Sikora, Mateusz K id: 2F74BCDE-F248-11E8-B48F-1D18A9856A87 last_name: Sikora citation: ama: Schmalhorst PS, Deluweit F, Scherrers R, Heisenberg C-PJ, Sikora MK. Overcoming the limitations of the MARTINI force field in simulations of polysaccharides. Journal of Chemical Theory and Computation. 2017;13(10):5039-5053. doi:10.1021/acs.jctc.7b00374 apa: Schmalhorst, P. S., Deluweit, F., Scherrers, R., Heisenberg, C.-P. J., & Sikora, M. K. (2017). Overcoming the limitations of the MARTINI force field in simulations of polysaccharides. Journal of Chemical Theory and Computation. American Chemical Society. https://doi.org/10.1021/acs.jctc.7b00374 chicago: Schmalhorst, Philipp S, Felix Deluweit, Roger Scherrers, Carl-Philipp J Heisenberg, and Mateusz K Sikora. “Overcoming the Limitations of the MARTINI Force Field in Simulations of Polysaccharides.” Journal of Chemical Theory and Computation. American Chemical Society, 2017. https://doi.org/10.1021/acs.jctc.7b00374. ieee: P. S. Schmalhorst, F. Deluweit, R. Scherrers, C.-P. J. Heisenberg, and M. K. Sikora, “Overcoming the limitations of the MARTINI force field in simulations of polysaccharides,” Journal of Chemical Theory and Computation, vol. 13, no. 10. American Chemical Society, pp. 5039–5053, 2017. ista: Schmalhorst PS, Deluweit F, Scherrers R, Heisenberg C-PJ, Sikora MK. 2017. Overcoming the limitations of the MARTINI force field in simulations of polysaccharides. Journal of Chemical Theory and Computation. 13(10), 5039–5053. mla: Schmalhorst, Philipp S., et al. “Overcoming the Limitations of the MARTINI Force Field in Simulations of Polysaccharides.” Journal of Chemical Theory and Computation, vol. 13, no. 10, American Chemical Society, 2017, pp. 5039–53, doi:10.1021/acs.jctc.7b00374. short: P.S. Schmalhorst, F. Deluweit, R. Scherrers, C.-P.J. Heisenberg, M.K. Sikora, Journal of Chemical Theory and Computation 13 (2017) 5039–5053. date_created: 2018-12-11T11:48:35Z date_published: 2017-10-10T00:00:00Z date_updated: 2023-09-27T10:58:45Z day: '10' department: - _id: CaHe doi: 10.1021/acs.jctc.7b00374 external_id: isi: - '000412965700036' intvolume: ' 13' isi: 1 issue: '10' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1704.03773 month: '10' oa: 1 oa_version: Submitted Version page: 5039 - 5053 publication: Journal of Chemical Theory and Computation publication_identifier: issn: - '15499618' publication_status: published publisher: American Chemical Society publist_id: '6847' quality_controlled: '1' scopus_import: '1' status: public title: Overcoming the limitations of the MARTINI force field in simulations of polysaccharides type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 13 year: '2017' ... --- _id: '802' abstract: - lang: eng text: Glycoinositolphosphoceramides (GIPCs) are complex sphingolipids present at the plasma membrane of various eukaryotes with the important exception of mammals. In fungi, these glycosphingolipids commonly contain an alpha-mannose residue (Man) linked at position 2 of the inositol. However, several pathogenic fungi additionally synthesize zwitterionic GIPCs carrying an alpha-glucosamine residue (GlcN) at this position. In the human pathogen Aspergillus fumigatus, the GlcNalpha1,2IPC core (where IPC is inositolphosphoceramide) is elongated to Manalpha1,3Manalpha1,6GlcNalpha1,2IPC, which is the most abundant GIPC synthesized by this fungus. In this study, we identified an A. fumigatus N-acetylglucosaminyltransferase, named GntA, and demonstrate its involvement in the initiation of zwitterionic GIPC biosynthesis. Targeted deletion of the gene encoding GntA in A. fumigatus resulted in complete absence of zwitterionic GIPC; a phenotype that could be reverted by episomal expression of GntA in the mutant. The N-acetylhexosaminyltransferase activity of GntA was substantiated by production of N-acetylhexosamine-IPC in the yeast Saccharomyces cerevisiae upon GntA expression. Using an in vitro assay, GntA was furthermore shown to use UDP-N-acetylglucosamine as donor substrate to generate a glycolipid product resistant to saponification and to digestion by phosphatidylinositol-phospholipase C as expected for GlcNAcalpha1,2IPC. Finally, as the enzymes involved in mannosylation of IPC, GntA was localized to the Golgi apparatus, the site of IPC synthesis. author: - first_name: Jakob full_name: Engel, Jakob last_name: Engel - first_name: Philipp S full_name: Schmalhorst, Philipp S id: 309D50DA-F248-11E8-B48F-1D18A9856A87 last_name: Schmalhorst orcid: 0000-0002-5795-0133 - first_name: Anke full_name: Kruger, Anke last_name: Kruger - first_name: Christina full_name: Muller, Christina last_name: Muller - first_name: Falk full_name: Buettner, Falk last_name: Buettner - first_name: Françoise full_name: Routier, Françoise last_name: Routier citation: ama: Engel J, Schmalhorst PS, Kruger A, Muller C, Buettner F, Routier F. Characterization of an N-acetylglucosaminyltransferase involved in Aspergillus fumigatus zwitterionic glycoinositolphosphoceramide biosynthesis. Glycobiology. 2015;25(12):1423-1430. doi:10.1093/glycob/cwv059 apa: Engel, J., Schmalhorst, P. S., Kruger, A., Muller, C., Buettner, F., & Routier, F. (2015). Characterization of an N-acetylglucosaminyltransferase involved in Aspergillus fumigatus zwitterionic glycoinositolphosphoceramide biosynthesis. Glycobiology. Oxford University Press. https://doi.org/10.1093/glycob/cwv059 chicago: Engel, Jakob, Philipp S Schmalhorst, Anke Kruger, Christina Muller, Falk Buettner, and Françoise Routier. “Characterization of an N-Acetylglucosaminyltransferase Involved in Aspergillus Fumigatus Zwitterionic Glycoinositolphosphoceramide Biosynthesis.” Glycobiology. Oxford University Press, 2015. https://doi.org/10.1093/glycob/cwv059. ieee: J. Engel, P. S. Schmalhorst, A. Kruger, C. Muller, F. Buettner, and F. Routier, “Characterization of an N-acetylglucosaminyltransferase involved in Aspergillus fumigatus zwitterionic glycoinositolphosphoceramide biosynthesis,” Glycobiology, vol. 25, no. 12. Oxford University Press, pp. 1423–1430, 2015. ista: Engel J, Schmalhorst PS, Kruger A, Muller C, Buettner F, Routier F. 2015. Characterization of an N-acetylglucosaminyltransferase involved in Aspergillus fumigatus zwitterionic glycoinositolphosphoceramide biosynthesis. Glycobiology. 25(12), 1423–1430. mla: Engel, Jakob, et al. “Characterization of an N-Acetylglucosaminyltransferase Involved in Aspergillus Fumigatus Zwitterionic Glycoinositolphosphoceramide Biosynthesis.” Glycobiology, vol. 25, no. 12, Oxford University Press, 2015, pp. 1423–30, doi:10.1093/glycob/cwv059. short: J. Engel, P.S. Schmalhorst, A. Kruger, C. Muller, F. Buettner, F. Routier, Glycobiology 25 (2015) 1423–1430. date_created: 2018-12-11T11:48:35Z date_published: 2015-12-01T00:00:00Z date_updated: 2021-01-12T08:16:33Z day: '01' department: - _id: CaHe doi: 10.1093/glycob/cwv059 external_id: pmid: - '26306635' intvolume: ' 25' issue: '12' language: - iso: eng month: '12' oa_version: None page: 1423 - 1430 pmid: 1 publication: Glycobiology publication_status: published publisher: Oxford University Press publist_id: '6851' quality_controlled: '1' scopus_import: 1 status: public title: Characterization of an N-acetylglucosaminyltransferase involved in Aspergillus fumigatus zwitterionic glycoinositolphosphoceramide biosynthesis type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 25 year: '2015' ... --- _id: '801' abstract: - lang: eng text: Fungal cell walls frequently contain a polymer of mannose and galactose called galactomannan. In the pathogenic filamentous fungus Aspergillus fumigatus, this polysaccharide is made of a linear mannan backbone with side chains of galactofuran and is anchored to the plasma membrane via a glycosylphosphatidylinositol or is covalently linked to the cell wall. To date, the biosynthesis and significance of this polysaccharide are unknown. The present data demonstrate that deletion of the Golgi UDP-galactofuranose transporter GlfB or the GDP-mannose transporter GmtA leads to the absence of galactofuran or galactomannan, respectively. This indicates that the biosynthesis of galactomannan probably occurs in the lumen of the Golgi apparatus and thus contrasts with the biosynthesis of other fungal cell wall polysaccharides studied to date that takes place at the plasma membrane. Transglycosylation of galactomannan from the membrane to the cell wall is hypothesized because both the cell wall-bound and membrane-bound polysaccharide forms are affected in the generated mutants. Considering the severe growth defect of the A. fumigatus GmtA-deficient mutant, proving this paradigm might provide new targets for antifungal therapy. acknowledgement: This work was supported by the Deutsche Forschungsgemeinschaft. article_processing_charge: No article_type: original author: - first_name: Jakob full_name: Engel, Jakob last_name: Engel - first_name: Philipp S full_name: Schmalhorst, Philipp S id: 309D50DA-F248-11E8-B48F-1D18A9856A87 last_name: Schmalhorst orcid: 0000-0002-5795-0133 - first_name: Françoise full_name: Routier, Françoise last_name: Routier citation: ama: Engel J, Schmalhorst PS, Routier F. Biosynthesis of the fungal cell wall polysaccharide galactomannan requires intraluminal GDP-mannose. Journal of Biological Chemistry. 2012;287(53):44418-44424. doi:10.1074/jbc.M112.398321 apa: Engel, J., Schmalhorst, P. S., & Routier, F. (2012). Biosynthesis of the fungal cell wall polysaccharide galactomannan requires intraluminal GDP-mannose. Journal of Biological Chemistry. American Society for Biochemistry and Molecular Biology. https://doi.org/10.1074/jbc.M112.398321 chicago: Engel, Jakob, Philipp S Schmalhorst, and Françoise Routier. “Biosynthesis of the Fungal Cell Wall Polysaccharide Galactomannan Requires Intraluminal GDP-Mannose.” Journal of Biological Chemistry. American Society for Biochemistry and Molecular Biology, 2012. https://doi.org/10.1074/jbc.M112.398321. ieee: J. Engel, P. S. Schmalhorst, and F. Routier, “Biosynthesis of the fungal cell wall polysaccharide galactomannan requires intraluminal GDP-mannose,” Journal of Biological Chemistry, vol. 287, no. 53. American Society for Biochemistry and Molecular Biology, pp. 44418–44424, 2012. ista: Engel J, Schmalhorst PS, Routier F. 2012. Biosynthesis of the fungal cell wall polysaccharide galactomannan requires intraluminal GDP-mannose. Journal of Biological Chemistry. 287(53), 44418–44424. mla: Engel, Jakob, et al. “Biosynthesis of the Fungal Cell Wall Polysaccharide Galactomannan Requires Intraluminal GDP-Mannose.” Journal of Biological Chemistry, vol. 287, no. 53, American Society for Biochemistry and Molecular Biology, 2012, pp. 44418–24, doi:10.1074/jbc.M112.398321. short: J. Engel, P.S. Schmalhorst, F. Routier, Journal of Biological Chemistry 287 (2012) 44418–44424. date_created: 2018-12-11T11:48:34Z date_published: 2012-12-28T00:00:00Z date_updated: 2022-03-21T07:57:14Z day: '28' doi: 10.1074/jbc.M112.398321 extern: '1' external_id: pmid: - '23139423' intvolume: ' 287' issue: '53' language: - iso: eng month: '12' oa_version: None page: 44418 - 44424 pmid: 1 publication: Journal of Biological Chemistry publication_status: published publisher: American Society for Biochemistry and Molecular Biology publist_id: '6852' quality_controlled: '1' scopus_import: '1' status: public title: Biosynthesis of the fungal cell wall polysaccharide galactomannan requires intraluminal GDP-mannose type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 287 year: '2012' ... --- _id: '3292' abstract: - lang: eng text: Galactofuranose (Galf) containing molecules have been described at the cell surface of several eukaryotes and shown to contribute to the virulence of the parasite Leishmania major and the fungus Aspergillus fumigatus. It is anticipated that a number of the surface glycoconjugates such as N-glycans or glycolipids are galactofuranosylated in the Golgi apparatus. This raises the question of how the substrate for galactofuranosylation reactions, UDP-Galf, which is synthesized in the cytosol, translocates into the organelles of the secretory pathway. Here we report the first identification of a Golgi-localized nucleotide sugar transporter, named GlfB, with specificity for a UDP-Galf. In vitro transport assays established binding of UDP-Galf to GlfB and excluded transport of several other nucleotide sugars. Furthermore, the implication of glfB in the galactofuranosylation of A. fumigatus glycoconjugates and galactomannan was demonstrated by a targeted gene deletion approach. Our data reveal a direct connection between galactomannan and the organelles of the secretory pathway that strongly suggests that the cell wall-bound polysaccharide originates from its glycosylphosphatidylinositol-anchored form. author: - first_name: Jakob full_name: Engel, Jakob last_name: Engel - first_name: Philipp S full_name: Schmalhorst, Philipp S id: 309D50DA-F248-11E8-B48F-1D18A9856A87 last_name: Schmalhorst orcid: 0000-0002-5795-0133 - first_name: Thilo full_name: Dörk Bousset, Thilo last_name: Dörk Bousset - first_name: Vincent full_name: Ferrières, Vincent last_name: Ferrières - first_name: Françoise full_name: Routier, Françoise last_name: Routier citation: ama: Engel J, Schmalhorst PS, Dörk Bousset T, Ferrières V, Routier F. A single UDP galactofuranose transporter is required for galactofuranosylation in Aspergillus fumigatus. Journal of Biological Chemistry. 2009;284(49):33859-33868. doi:10.1074/jbc.M109.070219 apa: Engel, J., Schmalhorst, P. S., Dörk Bousset, T., Ferrières, V., & Routier, F. (2009). A single UDP galactofuranose transporter is required for galactofuranosylation in Aspergillus fumigatus. Journal of Biological Chemistry. American Society for Biochemistry and Molecular Biology. https://doi.org/10.1074/jbc.M109.070219 chicago: Engel, Jakob, Philipp S Schmalhorst, Thilo Dörk Bousset, Vincent Ferrières, and Françoise Routier. “A Single UDP Galactofuranose Transporter Is Required for Galactofuranosylation in Aspergillus Fumigatus.” Journal of Biological Chemistry. American Society for Biochemistry and Molecular Biology, 2009. https://doi.org/10.1074/jbc.M109.070219 . ieee: J. Engel, P. S. Schmalhorst, T. Dörk Bousset, V. Ferrières, and F. Routier, “A single UDP galactofuranose transporter is required for galactofuranosylation in Aspergillus fumigatus,” Journal of Biological Chemistry, vol. 284, no. 49. American Society for Biochemistry and Molecular Biology, pp. 33859–33868, 2009. ista: Engel J, Schmalhorst PS, Dörk Bousset T, Ferrières V, Routier F. 2009. A single UDP galactofuranose transporter is required for galactofuranosylation in Aspergillus fumigatus. Journal of Biological Chemistry. 284(49), 33859–33868. mla: Engel, Jakob, et al. “A Single UDP Galactofuranose Transporter Is Required for Galactofuranosylation in Aspergillus Fumigatus.” Journal of Biological Chemistry, vol. 284, no. 49, American Society for Biochemistry and Molecular Biology, 2009, pp. 33859–68, doi:10.1074/jbc.M109.070219 . short: J. Engel, P.S. Schmalhorst, T. Dörk Bousset, V. Ferrières, F. Routier, Journal of Biological Chemistry 284 (2009) 33859–33868. date_created: 2018-12-11T12:02:30Z date_published: 2009-12-04T00:00:00Z date_updated: 2021-01-12T07:42:26Z day: '04' doi: '10.1074/jbc.M109.070219 ' extern: '1' intvolume: ' 284' issue: '49' language: - iso: eng month: '12' oa_version: None page: 33859 - 33868 publication: Journal of Biological Chemistry publication_status: published publisher: American Society for Biochemistry and Molecular Biology publist_id: '3353' quality_controlled: '1' status: public title: A single UDP galactofuranose transporter is required for galactofuranosylation in Aspergillus fumigatus type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 284 year: '2009' ... --- _id: '3400' abstract: - lang: eng text: |- Invasive fungal infections pose a serious threat to immunocompromised people. Most of these infections are caused by either Candida or Aspergillus species, with A. fumigatus being the predominant causative agent of Invasive Aspergillosis. Affected people comprise mainly haematopoietic stem cell or solid organ transplant patients who receive either high-dose corticosteroids or immunosuppressants. These risk factors predispose to the development of Invasive Aspergillosis which is lethal in 20 to 80 % of the cases, largely due to insufficient efficacy of current antifungal therapy. Thus one major aim in current mycological research is the identification of new drug targets. The polysaccharide-based fungal cell wall is both essential to fungi and absent from human cells which makes it appear an attractive new target. Notably, many components of the A. fumigatus cell wall, including the polysaccharide galactomannan, glycoproteins, and glycolipids, contain the unusual sugar galactofuranose (Galf). In contrast to the other cell wall monosaccharides, Galf does not occur on human cells but is known as component of cell surface molecules of many pathogenic bacteria and protozoa, such as Mycobacterium tuberculosis or Leishmania major. These molecules are often essential for virulence or viability of these organisms which suggested a possible role of Galf in the pathogenicity of A. fumigatus. To address the importance of Galf in A. fumigatus, the key biosynthesis gene glfA, encoding UDPgalactopyranose mutase (UGM), was deleted. In different experimental approaches it was demonstrated that the absence of the glfA gene led to a complete loss of Galf-containing glycans. Analysis of the DeltaglfA phenotype revealed growth and sporulation defects, reduced thermotolerance and an increased susceptibility to antifungal drugs. Electron Microscopy indicated a cell wall defect as a likely cause for the observed impairments. Furthermore, the virulence of the DeltaglfA mutant was found to be severely attenuated in a murine model of Invasive Aspergillosis. The second focus of this study was laid on further elucidation of the galactofuranosylation pathway in A. fumigatus. In eukaryotes, a UDP-Galf transporter is likely required to transport UDP-Galf from the cytosol into the organelles of the secretory pathway, but no such activity had been described. Sixteen candidate genes were identified in the A. fumigatus genome of which one, glfB, was found in close proximity to the glfA gene. In vitro transport assays revealed specificity of GlfB for UDP-Galf suggesting that glfB encoded indeed a UDP-Galf transporter. The influence of glfB on galactofuranosylation was determined by a DeltaglfB deletion mutant, which closely recapitulated the DeltaglfA phenotype and was likewise found to be completely devoid of Galf. It could be concluded that all galactofuranosylation processes in A. fumigatus occur in the secretory pathway, including the biosynthesis of the cell wall polysaccharide galactomannan whose subcellular origin was previously disputed. Thus in the course of this study the first UDP-Galf specific nucleotide sugar transporter was identified and its requirement for galactofuranosylation in A. fumigatus demonstrated. Moreover, it was shown that blocking the galactofuranosylation pathway impaired virulence of A. fumigatus which suggests the UDP-Galf biosynthesis enzyme UGM as a target for new antifungal drugs. author: - first_name: Philipp S full_name: Philipp Schmalhorst id: 309D50DA-F248-11E8-B48F-1D18A9856A87 last_name: Schmalhorst orcid: 0000-0002-5795-0133 citation: ama: Schmalhorst PS. Biosynthesis of Galactofuranose Containing Glycans and Their Relevance for the Pathogenic Fungus Aspergillus fumigatus. 2009:1-72. apa: Schmalhorst, P. S. (2009). Biosynthesis of Galactofuranose Containing Glycans and Their Relevance for the Pathogenic Fungus Aspergillus fumigatus. Gottfried Wilhelm Leibniz Universität Hannover. chicago: Schmalhorst, Philipp S. “Biosynthesis of Galactofuranose Containing Glycans and Their Relevance for the Pathogenic Fungus Aspergillus Fumigatus.” Gottfried Wilhelm Leibniz Universität Hannover, 2009. ieee: P. S. Schmalhorst, “Biosynthesis of Galactofuranose Containing Glycans and Their Relevance for the Pathogenic Fungus Aspergillus fumigatus,” Gottfried Wilhelm Leibniz Universität Hannover, 2009. ista: Schmalhorst PS. 2009. Biosynthesis of Galactofuranose Containing Glycans and Their Relevance for the Pathogenic Fungus Aspergillus fumigatus. Gottfried Wilhelm Leibniz Universität Hannover. mla: Schmalhorst, Philipp S. Biosynthesis of Galactofuranose Containing Glycans and Their Relevance for the Pathogenic Fungus Aspergillus Fumigatus. Gottfried Wilhelm Leibniz Universität Hannover, 2009, pp. 1–72. short: P.S. Schmalhorst, Biosynthesis of Galactofuranose Containing Glycans and Their Relevance for the Pathogenic Fungus Aspergillus Fumigatus, Gottfried Wilhelm Leibniz Universität Hannover, 2009. date_created: 2018-12-11T12:03:07Z date_published: 2009-08-13T00:00:00Z date_updated: 2021-01-12T07:43:13Z day: '13' extern: 1 main_file_link: - open_access: '0' url: http://edok01.tib.uni-hannover.de/edoks/e01dh09/609861891.pdf month: '08' page: 1 - 72 publication_status: published publisher: Gottfried Wilhelm Leibniz Universität Hannover publist_id: '3058' quality_controlled: 0 status: public title: Biosynthesis of Galactofuranose Containing Glycans and Their Relevance for the Pathogenic Fungus Aspergillus fumigatus type: dissertation year: '2009' ... --- _id: '3291' abstract: - lang: eng text: 'The filamentous fungus Aspergillus fumigatus is responsible for a lethal disease called Invasive Aspergillosis that affects immunocompromised patients. This disease, like other human fungal diseases, is generally treated by compounds targeting the primary fungal cell membrane sterol. Recently, glucan synthesis inhibitors were added to the limited antifungal arsenal and encouraged the search for novel targets in cell wall biosynthesis. Although galactomannan is a major component of the A. fumigatus cell wall and extracellular matrix, the biosynthesis and role of galactomannan are currently unknown. By a targeted gene deletion approach, we demonstrate that UDP-galactopyranose mutase, a key enzyme of galactofuranose metabolism, controls the biosynthesis of galactomannan and galactofuranose containing glycoconjugates. The glfA deletion mutant generated in this study is devoid of galactofuranose and displays attenuated virulence in a low-dose mouse model of invasive aspergillosis that likely reflects the impaired growth of the mutant at mammalian body temperature. Furthermore, the absence of galactofuranose results in a thinner cell wall that correlates with an increased susceptibility to several antifungal agents. The UDP-galactopyranose mutase thus appears to be an appealing adjunct therapeutic target in combination with other drugs against A. fumigatus. Its absence from mammalian cells indeed offers a considerable advantage to achieve therapeutic selectivity. ' author: - first_name: Philipp S full_name: Philipp Schmalhorst id: 309D50DA-F248-11E8-B48F-1D18A9856A87 last_name: Schmalhorst orcid: 0000-0002-5795-0133 - first_name: Sven full_name: Krappmann, Sven last_name: Krappmann - first_name: Wouter full_name: Vervecken, Wouter last_name: Vervecken - first_name: Manfred full_name: Rohde, Manfred last_name: Rohde - first_name: Meike full_name: Müller, Meike last_name: Müller - first_name: Gerhard full_name: Braus, Gerhard H. last_name: Braus - first_name: Roland full_name: Contreras, Roland last_name: Contreras - first_name: Armin full_name: Braun, Armin last_name: Braun - first_name: Hans full_name: Bakker, Hans last_name: Bakker - first_name: Françoise full_name: Routier, Françoise H last_name: Routier citation: ama: Schmalhorst PS, Krappmann S, Vervecken W, et al. Contribution of galactofuranose to the virulence of the opportunistic pathogen Aspergillus fumigatus. Eukaryotic Cell. 2008;7(8):1268-1277. doi:10.1128/EC.00065-08 apa: Schmalhorst, P. S., Krappmann, S., Vervecken, W., Rohde, M., Müller, M., Braus, G., … Routier, F. (2008). Contribution of galactofuranose to the virulence of the opportunistic pathogen Aspergillus fumigatus. Eukaryotic Cell. American Society for Microbiology. https://doi.org/10.1128/EC.00065-08 chicago: Schmalhorst, Philipp S, Sven Krappmann, Wouter Vervecken, Manfred Rohde, Meike Müller, Gerhard Braus, Roland Contreras, Armin Braun, Hans Bakker, and Françoise Routier. “Contribution of Galactofuranose to the Virulence of the Opportunistic Pathogen Aspergillus Fumigatus.” Eukaryotic Cell. American Society for Microbiology, 2008. https://doi.org/10.1128/EC.00065-08. ieee: P. S. Schmalhorst et al., “Contribution of galactofuranose to the virulence of the opportunistic pathogen Aspergillus fumigatus,” Eukaryotic Cell, vol. 7, no. 8. American Society for Microbiology, pp. 1268–1277, 2008. ista: Schmalhorst PS, Krappmann S, Vervecken W, Rohde M, Müller M, Braus G, Contreras R, Braun A, Bakker H, Routier F. 2008. Contribution of galactofuranose to the virulence of the opportunistic pathogen Aspergillus fumigatus. Eukaryotic Cell. 7(8), 1268–1277. mla: Schmalhorst, Philipp S., et al. “Contribution of Galactofuranose to the Virulence of the Opportunistic Pathogen Aspergillus Fumigatus.” Eukaryotic Cell, vol. 7, no. 8, American Society for Microbiology, 2008, pp. 1268–77, doi:10.1128/EC.00065-08. short: P.S. Schmalhorst, S. Krappmann, W. Vervecken, M. Rohde, M. Müller, G. Braus, R. Contreras, A. Braun, H. Bakker, F. Routier, Eukaryotic Cell 7 (2008) 1268–1277. date_created: 2018-12-11T12:02:29Z date_published: 2008-06-13T00:00:00Z date_updated: 2021-01-12T07:42:26Z day: '13' doi: 10.1128/EC.00065-08 extern: 1 intvolume: ' 7' issue: '8' month: '06' page: 1268 - 1277 publication: Eukaryotic Cell publication_status: published publisher: American Society for Microbiology publist_id: '3354' quality_controlled: 0 status: public title: Contribution of galactofuranose to the virulence of the opportunistic pathogen Aspergillus fumigatus type: journal_article volume: 7 year: '2008' ...