title: Ergosteryl-β-glucosidase (Egh1) involved in sterylglucoside catabolism and vacuole formation in Saccharomyces cerevisiae.
abstract: Sterylglucosides (SGs) are composed of a glucose and sterol derivatives, and are distributed in fungi, plants and mammals. We recently identified EGCrP1 and EGCrP2 (endoglycoceramidase-related proteins 1 and 2) as a β-glucocerebrosidase and steryl-β-glucosidase, respectively, in Cryptococcus neoformans. We herein describe an EGCrP2 homologue (Egh1; ORF name, Yir007w) involved in SG catabolism in Saccharomyces cerevisiae. The purified recombinant Egh1 hydrolyzed various β-glucosides including ergosteryl β-glucoside (EG), cholesteryl β-glucoside, sitosteryl β-glucoside, para-nitrophenyl β-glucoside, 4-methylumberifellyl β-glucoside and glucosylceramide. The disruption of EGH1 in S. cerevisiae BY4741 (egh1Δ) resulted in the accumulation of EG and fragmentation of vacuoles. The expression of EGH1 in egh1Δ (revertant) reduced the accumulation of EG, and restored the morphology of vacuoles. The accumulation of EG was not detected in EGH1 and UGT51(ATG26) double-disrupted mutants (ugt51Δegh1Δ), indicating that EG was synthesized by Ugt51(Atg26) and degraded by Egh1 in vivo. These results clearly demonstrated that Egh1 is an ergosteryl-β-glucosidase that is functionally involved in the EG catabolic pathway and vacuole formation in S. cerevisiae.
authors.affiliation: Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences.
authors.forename: Takashi
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Chemistry, Faculty of Science, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Tani
authors.affiliation: Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Ishibashi
authors.affiliation: Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences.
authors.forename: Ikumi
authors.initials: I
authors.lastname: Endo
authors.affiliation: Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences.
authors.forename: Nozomu
authors.initials: N
authors.lastname: Okino
authors.affiliation: Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences makotoi@agr.kyushu-u.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ito
mesh_terms: D000595:Amino Acid Sequence; D005959:Glucosidases / Q000737:chemistry / Q000502:physiology*; D005960:Glucosides / Q000378:metabolism*; D006017:Glycolipids / Q000378:metabolism; D050356:Lipid Metabolism; D008969:Molecular Sequence Data; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000502:physiology*; D014617:Vacuoles / Q000201:enzymology* / Q000648:ultrastructure
chemical_list: D005960:Glucosides; D006017:Glycolipids; D029701:Saccharomyces cerevisiae Proteins; C000608259:Egh1 protein, S cerevisiae; D005959:Glucosidases
keywords: Saccharomyces cerevisiae; ergosteryl-β-glucosidase; glycolipid; sterylglucoside