H941 Department für Angewandte Genetik und Zellbiologie (DAGZ)
Arbeitsgruppen
H94 Department für angewandte Genetik und Zellbiologie (DAGZ)
H941 Department für Angewandte Genetik und Zellbiologie (DAGZ) Arbeitsgruppen AG Strasser
Pflanzenglykobiologie
Gebiet
N-Glykan-Biosynthese in Pflanzen, physiologische Funktion von N-Glykanen in Pflanzen, intrazelluläre Transportprozesse von Glykosyltransferasen und Glykosidasen.
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Ausrichtung
Charakterisierung der molekularen Grundlagen der N-Glykosilierung von Proteinen in Arabidopsis thaliana. Analyse der Funktion von N-Glykanen mittels zellbiologischer, molekularbiologischer und biochemischer Methoden.
Projekte
Ausgewählte Projekte
The main focus of our research is the investigation of the N-glycosylation pathway and the biological function of N-glycans in plants. During the last ten years we have characterized a set of mutants with clearly defined defects in N-glycan processing. These mutants are valuable tools to determine the role of individual glycoforms in a given process. We are especially interested to elucidate the biological significance of the final steps of N-glycan processing, which involve attachment of β1,2-linked xylose/core α1,3-linked fucose, removal of terminal GlcNAc residues by N-acetylhexosaminidases and the attachment of β1,3-galactose and α1,4-fucose to terminal GlcNAc residues.
In eukaryotes secreted proteins are subjected to a quality control system in the endoplasmic reticulum (ER), which retains newly synthesized polypeptides until they reach their correct conformation or targets potentially misfolded proteins for degradation. Both processes involve glycan-dependent chaperones and glycan trimming. While these quality control mechanisms are intensively studied in yeast and mammals, much less is known in plants. In this context we study the role of a family of A. thaliana class I α-mannosidases, which could be involved in N-glycan trimming and ER-associated degradation of glycoproteins (ERAD).
Plant N-glycan processing enzymes are arranged along the early secretory pathway, forming an assembly line in order to facilitate the step-by-step modification of oligosaccharides on glycoproteins. Thus, these enzymes provide excellent tools to study signals and mechanisms promoting their localization and retention in the ER and Golgi apparatus. Our main objective is the analysis of putative targeting motifs present in glycosidases and glycosyltransferases and the identification of interacting proteins to obtain new insights into this fundamental cellular process. |
Figure 1. Processing steps of plant N-glycans in the ER and Golgi apparatus. GCSI: α-glucosidase I; GCSII: α-glucosidase II; ER-MI: ER-α-mannosidase I; GMI: Golgi-α-mannosidase I; GnTI: β1,2-N-acetylglucosaminyltransferase I; GMII: Golgi-α-mannosidase II; GnTII: β1,2-N-acetyl-glucosaminyltransferase II; XylT: β1,2-xylosyltransferase; FUT11/12: core α1,3-fucosyltransferase; GALT1: β1,3-galactosyltransferase; FUT13: α1,4-fucosyltransferase. |
Publikationen
ausgewählte Publikationen
Castilho, A., Neumann, L., Daskalova, S., Mason, H.S., Steinkellner, H., Altmann, F., Strasser, R. (2012) Engineering of Sialylated Mucin-type O-Glycosylation in Plants. The Journal of Biological Chemistry 287, 36518-36526.
Liebminger, E., Grass, J., Jez, J., Neumann, L., Altmann, F., Strasser, R. (2012) Myrosinases TGG1 and TGG2 from Arabidopsis thaliana contain exclusively oligomannosidic N-glycans. Phytochemistry, 84, 24-30.
Hüttner, S., Strasser, R. (2012) Endoplasmic reticulum-associated degradation of glycoproteins in plants. Frontiers in Plant Sciences 3: 67.
Hüttner, S., Veit, C., Schoberer, J., Grass, J., Strasser, R. (2012) Unraveling the function of Arabidopsis thaliana OS9 in the endoplasmic reticulum-associated degradation of glycoproteins. Plant Molecular Biology 79, 21-33.
Farid, A., Pabst, M., Schoberer, J., Altmann, F., Glössl, J., Strasser, R. (2011) Arabidopsis thaliana alpha1,2-glucosyltransferase (ALG10) is required for efficient N-glycosylation and leaf growth. Plant Journal 68, 314-325.
Liebminger, E., Veit, C., Pabst, M., Batoux, M., Zipfel, C., Altmann, F., Mach, L., Strasser, R. (2011) -N-acetylhexosaminidases HEXO1 and HEXO3 are responsible for the formation of paucimannosidic N-glycans in Arabidopsis thaliana. The Journal of Biological Chemistry 286, 10793-10802.
Castilho, A., Gattinger, P., Grass, J., Jez, J., Pabst, M., Altmann, F., Gorfer, M., Strasser, R., Steinkellner, H. (2011) N-glycosylation engineering of plants for the biosynthesis of glycoproteins with bisected and branched complex N-glycans. Glycobiology, 21, 813-823.
Schoberer, J., Strasser, R. (2011) Sub-Compartmental Organization of Golgi-Resident N-Glycan Processing Enzymes in Plants. Molecular Plant, 4, 220-228.
Schoberer, J., Runions, J., Steinkellner, H., Strasser, R., Hawes, C., Osterrieder, A. (2010) Sequential depletion and acquisition of proteins during Golgi stack disassembly and reformation. Traffic 11, 1429-1444.
Castilho, A., Strasser, R., Stadlmann, J., Grass, J., Jez, J., Gattinger, P., Kunert, R., Quendler, H., Pabst, M., Leonard, R., Altmann, F., Steinkellner, H. (2010) In planta protein sialylation through overexpression of the respective mammalian pathway. The Journal of Biological Chemistry 285, 15923-15930.
Liebminger, E., Hüttner, S., Vavra, U., Fischl, R., Schoberer, J., Grass, J., Blaukopf, C., Seifert, G.J., Altmann, F., Mach, L., Strasser, R. (2009) Class I alpha-mannosidases are required for N-glycan processing and root development in Arabidopsis thaliana. Plant Cell 21, 3850-3867.
Strasser, R., Bondili, J.S., Vavra, U., Schoberer, J., Svoboda, B., Glössl, J., Leonard, R., Stadlmann, J., Altmann, F., Steinkellner, H. and Mach, L. (2007) A unique 1,3-galactosyltransferase is indispensable for the biosynthesis of N-glycans containing Lewis a structures in Arabidopsis thaliana. Plant Cell 19, 2278-2292.
Förderungsorganisationen
| Fonds zur Förderung der Wissenschaftlichen Forschung (Austrian Science Funds) |
Kooperationen
Hugh S. Mason, Biodesign Institute, Arizona State University, Tempe, USA
Friedrich Altmann, Department of Chemistry, BOKU, Vienna, Austria
Chris Hawes, Oxford Brookes University, Oxford, UK
Cyril Zipfel, The Sainsbury Laboratory, Norwich, UK
