title: Aspergillus fumigatus Cap59-like protein A is involved in α1,3-mannosylation of GPI-anchors.
abstract: Glycosylphosphatidylinositol (GPI) attaches a variety of eukaryotic proteins to the outer leaflet of the plasma membrane. In fungi, these proteins may also be transferred to the cell wall, to which they are covalently linked via a remnant of the GPI-anchor. They play crucial physiological roles in cell-cell interactions, adhesion or cell wall biogenesis. The biosynthesis of GPI-anchors in the endoplasmic reticulum, their transfer to proteins, early remodelling and transport to the Golgi apparatus has been fairly well described. In contrast, almost nothing is known about the genes and enzymes involved in adding glycan side chains to GPI after protein attachment. In this study, we characterized an α1,3-mannosyltransferase involved in maturation of GPI-anchors from the pathogenic fungus Aspergillus fumigatus. This enzyme shows homology to Cryptococcus neoformans Cap59p, a putative glycosyltransferase involved in capsule formation and virulence, and was thus named Cap59-like protein A (ClpA). Targeted deletion of the clpA gene in A. fumigatus led to absence of α1,3-mannose from mature GPI-anchors. The enzyme was further located to the Golgi-like apparatus of A. fumigatus and was shown to be active in the yeast Saccharomyces cerevisiae.
authors.affiliation: Department of Cellular Chemistry OE 4330, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Anke Tina
authors.initials: AT
authors.lastname: Krüger
authors.affiliation: Department of Cellular Chemistry OE 4330, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Jakob
authors.initials: J
authors.lastname: Engel
authors.affiliation: Department of Cellular Chemistry OE 4330, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Falk F R
authors.initials: FF
authors.lastname: Buettner
authors.affiliation: Department of Cellular Chemistry OE 4330, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany routier.francoise@mh-hannover.de.
authors.forename: Françoise H
authors.initials: FH
authors.lastname: Routier
mesh_terms: D000595:Amino Acid Sequence; D001232:Aspergillus fumigatus / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006056:Golgi Apparatus; D008358:Mannose / Q000378:metabolism*; D008364:Mannosyltransferases / Q000378:metabolism; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D012441:Saccharomyces cerevisiae / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D017261:Glycosylphosphatidylinositols; D008364:Mannosyltransferases; C121563:alpha 1,3-mannosyltransferase; D008358:Mannose
keywords: GPI; Golgi; fungi; glycosyltransferase; yeast