title: Identification of a novel glycan processing enzyme with exo-acting β-allosidase activity in the Golgi apparatus using a new platform for the synthesis of fluorescent substrates.
abstract: The majority of eukaryotic proteins undergo post-translational modifications (PTMs) involving the attachment of complex glycans, predominantly through N-glycosylation and O-glycosylation. PTMs play important roles in virtually all cellular processes, and aberrant regulation of protein glycosylation and glycan processing has been implicated in various diseases. However, glycan processing on proteins in various cellular contexts has not been visualized. We had previously developed a quinone methide cleavage (QMC) platform for enhanced substrate design. This platform was applied here to screen for novel glycan-processing enzymes. We designed and synthesized fluorescent substrates with β-allopyranoside residues using the QMC platform. When applied in cell-based assays, the fluorescent substrates allowed rapid and clear visualization of β-allosidase activity in the Golgi apparatus of human cultured cells. The QMC platform will likely find broad applications in visualizing the activities of glycan processing enzymes in living cells and in studying PTMs.
authors.affiliation: Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan. Electronic address: hakamata.wataru@nihon-u.ac.jp.
authors.forename: Wataru
authors.initials: W
authors.lastname: Hakamata
authors.affiliation: Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Miura
authors.affiliation: Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Hirano
authors.affiliation: Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Nishio
mesh_terms: D002460:Cell Line; D005456:Fluorescent Dyes / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D006056:Golgi Apparatus / Q000201:enzymology* / Q000378:metabolism; D006801:Humans; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D011499:Protein Processing, Post-Translational
chemical_list: D005456:Fluorescent Dyes; D006027:Glycosides; D011134:Polysaccharides
keywords: Fluorescent substrate; Glycan processing; Golgi apparatus; Post-translational modification; Protein glycosylation; Quinone methide cleavage; β-Allosidase