title: GfsA encodes a novel galactofuranosyltransferase involved in biosynthesis of galactofuranose antigen of O-glycan in Aspergillus nidulans and Aspergillus fumigatus.
abstract: The cells walls of filamentous fungi in the genus Aspergillus have galactofuranose (Galf)-containing polysaccharides and glycoconjugates, including O-glycans, N-glycans, fungal-type galactomannan and glycosylinositolphosphoceramide, which are important for cell wall integrity. Here, we attempted to identify galactofuranosyltransferases that couple Galf monomers onto other wall components in Aspergillus nidulans. Using reverse-genetic and biochemical approaches, we identified that the AN8677 gene encoded a galactofuranosyltransferase, which we called GfsA, involved in Galf antigen biosynthesis. Disruption of gfsA reduced binding of β-Galf-specific antibody EB-A2 to O-glycosylated WscA protein and galactomannoproteins. The results of an in-vitro Galf antigen synthase assay revealed that GfsA has β1,5- or β1,6-galactofuranosyltransferase activity for O-glycans in glycoproteins, uses UDP-d-Galf as a sugar donor, and requires a divalent manganese cation for activity. GfsA was found to be localized at the Golgi apparatus based on cellular fractionation experiments. ΔgfsA cells exhibited an abnormal morphology characterized by poor hyphal extension, hyphal curvature and limited formation of conidia. Several gfsA orthologues were identified in members of the Pezizomycotina subphylum of Ascomycota, including the human pathogen Aspergillus fumigatus. To our knowledge, this is the first characterization of a fungal β-galactofuranosyltransferase, which was shown to be involved in Galf antigen biosynthesis of O-glycans in the Golgi.
authors.affiliation: Department of Applied Microbial Technology, Faculty of Biotechnology and Life Science, Sojo University, Kumamoto, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Komachi
authors.affiliation: Department of Applied Microbial Technology, Faculty of Biotechnology and Life Science, Sojo University, Kumamoto, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Hatakeyama
authors.affiliation: Department of Applied Microbial Technology, Faculty of Biotechnology and Life Science, Sojo University, Kumamoto, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Motomatsu
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
authors.forename: Taiki
authors.initials: T
authors.lastname: Futagami
authors.affiliation: Department of Biochemistry, Virginia Tech Blacksburg, VA, United States.
authors.forename: Karina
authors.initials: K
authors.lastname: Kizjakina
authors.affiliation: Department of Biochemistry, Virginia Tech Blacksburg, VA, United States.
authors.forename: Pablo
authors.initials: P
authors.lastname: Sobrado
authors.affiliation: Department of Applied Microbial Technology, Faculty of Biotechnology and Life Science, Sojo University, Kumamoto, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ekino
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Takegawa
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Goto
authors.affiliation: Department of Applied Microbial Technology, Faculty of Biotechnology and Life Science, Sojo University, Kumamoto, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Nomura
authors.affiliation: Department of Applied Microbial Technology, Faculty of Biotechnology and Life Science, Sojo University, Kumamoto, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Oka
mesh_terms: D000946:Antigens, Fungal / Q000096:biosynthesis* / Q000276:immunology*; D001232:Aspergillus fumigatus / Q000201:enzymology* / Q000235:genetics; D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics; D002473:Cell Wall / Q000378:metabolism; D062610:Fungal Polysaccharides / Q000096:biosynthesis* / Q000737:chemistry / Q000276:immunology; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005690:Galactose / Q000031:analogs & derivatives / Q000378:metabolism; D005700:Galactosyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005800:Genes, Fungal; D006001:Glycoconjugates; D006056:Golgi Apparatus / Q000378:metabolism; D025301:Hyphae / Q000378:metabolism; D059386:Reverse Genetics; D013172:Spores, Fungal / Q000378:metabolism; D014530:Uridine Diphosphate / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000946:Antigens, Fungal; D062610:Fungal Polysaccharides; D005656:Fungal Proteins; D006001:Glycoconjugates; C104136:uridine diphosphate galactofuranose; D014530:Uridine Diphosphate; D005700:Galactosyltransferases; D005690:Galactose