Structures of the glycosylphosphatidylinositol membrane anchors from Aspergillus fumigatus membrane proteins.
Glycosylphosphatidylinositol (GPI)-anchored proteins have been identified in all eukaryotes. In fungi, structural and biosynthetic studies of GPIs have been restricted to the yeast Saccharomyces cerevisiae. In this article, four GPI-anchored proteins were purified from a membrane preparation of the human filamentous fungal pathogen Aspergillus fumigatus. Using new methodology applied to western blot protein bands, the GPI structures were characterized by ES-MS, fluorescence labeling, HPLC, and specific enzymatic digestions. The phosphatidylinositol moiety of the A. fumigatus GPI membrane anchors was shown to be an inositol-phosphoceramide containing mainly phytosphingosine and monohydroxylated C24:0 fatty acid. In constrast to yeast, only ceramide was found in the GPI anchor structures of A. fumigatus, even for Gel1p, a homolog of Gas1p in S. cerevisiae that contains diacylglycerol. The A. fumigatus GPI glycan moiety is mainly a linear pentomannose structure linked to a glucosamine residue: Manalpha1-3Manalpha1-2Manalpha1-2Manalpha1-6Manalpha1-4GlcN.
Fontaine
Thierry
T
Unité Des Aspergillus, Institut Pasteur, 25 Rue Du Docteur Roux, 75724 Paris Cedex 15, France. tfontain@pasteur.fr
Magnin
Thierry
T
Melhert
Angela
A
Lamont
Douglas
D
Latge
Jean-Paul
JP
Ferguson
Michael A J
MA
D001232:Aspergillus fumigatus / Q000737:chemistry*; D015153:Blotting, Western; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D005656:Fungal Proteins / Q000737:chemistry*; D017261:Glycosylphosphatidylinositols / Q000737:chemistry*; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry
D005656:Fungal Proteins; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D010455:Peptides