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Characterization of the N-linked oligosaccharides of megalin (gp330) from rat kidney

Morelle, Willy ; Haslam, Stuart M. ; Ziak, Martin ; Roth, Jürgen ; Morris, Howard R. ; Dell, Anne

In: Glycobiology, 2000, vol. 10, no. 3, p. 295-304

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    Title
    • Characterization of the N-linked oligosaccharides of megalin (gp330) from rat kidney
    Author
    • Morelle, Willy
    • Haslam, Stuart M.
    • Ziak, Martin. Department of Biochemistry, Imperial College, London, SW7 2AY, UK and Department of Pathology, Division of Cell and Molecular Pathology, University of Zurich, CH-8091 Zurich, Switzerland
    • Roth, Jürgen. Department of Biochemistry, Imperial College, London, SW7 2AY, UK and Department of Pathology, Division of Cell and Molecular Pathology, University of Zurich, CH-8091 Zurich, Switzerland
    • Morris, Howard R.
    • Dell, Anne
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:298303
    Summary
    Megalin (gp 330) is a large cell surface receptor expressed on the apical surfaces of epithelial tissues, that mediates the binding and internalization of a number of structurally and functionally distinct ligands. In this paper we report the first detailed structural characterization of megalin-derived oligosaccharides. Using strategies based on mass spectrometric analysis, we have defined the structures of the N-glycans of megalin. The results reveal that megalin glycoprotein is heterogeneously glycosylated. The major N-glycans identified belong to the following two classes: high mannose structures and complex type structures, with complex structures being more abundant than high mannose structures. The major nonreducing epitopes in the complex-type glycans are: GlcNAc, Galβ1-4GlcNAc (LacNAc), NeuAcα2-6Galβ1-4GlcNAc (sialylated LacNAc), GalNAcβ1-4[NeuAcα2-3]Galβ1-4GlcNAc (Sda) and Galα1-3Galβ1-4GlcNAc. Most complex structures are characterized by the presence of (α1,6)-core fucosylation and the presence of a bisecting GlcNAc residue