title: Membrane-associated activation of cholesterol α-glucosyltransferase, an enzyme responsible for biosynthesis of cholesteryl-α-D-glucopyranoside in Helicobacter pylori critical for its survival.
abstract: Helicobacter pylori (H. pylori) is the causative pathogen underlying gastric diseases such as chronic gastritis and gastric cancer. Previously, the authors revealed that α1,4-linked N-acetylglucosamine-capped O-glycan (αGlcNAc) found in gland mucin suppresses H. pylori growth and motility by inhibiting catalytic activity of cholesterol α-glucosyltransferase (CHLαGcT), the enzyme responsible for biosynthesis of the major cell wall component cholesteryl-α-D-glucopyranoside (CGL). Here, the authors developed a polyclonal antibody specific for CHLαGcT and then undertook quantitative ultrastructural analysis of the enzyme's localization in H. pylori. They show that 66.3% of CHLαGcT is detected in the cytoplasm beneath the H. pylori inner membrane, whereas 24.7% is present on the inner membrane. In addition, 2.6%, 5.0%, and 1.4% of the protein were detected in the periplasm, on the outer membrane, and outside microbes, respectively. By using an in vitro CHLαGcT assay with fractionated H. pylori proteins, which were used as an enzyme source for CHLαGcT, the authors demonstrated that the membrane fraction formed CGL, whereas other fractions did not. These data combined together indicate that CHLαGcT is originally synthesized in the cytoplasm of H. pylori as an inactive form and then activated when it is associated with the cell membrane. This article contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.
authors.affiliation: Department of Pathology, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Hoshino
authors.forename: Akiko
authors.initials: A
authors.lastname: Tsuchida
authors.forename: Kiyokazu
authors.initials: K
authors.lastname: Kametani
authors.forename: Masako
authors.initials: M
authors.lastname: Mori
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nishizawa
authors.forename: Takefumi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Hitomi
authors.initials: H
authors.lastname: Nakamura
authors.forename: Heeseob
authors.initials: H
authors.lastname: Lee
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ito
authors.forename: Motohiro
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Junya
authors.initials: J
authors.lastname: Masumoto
authors.forename: Masaya
authors.initials: M
authors.lastname: Fujita
authors.forename: Minoru
authors.initials: M
authors.lastname: Fukuda
authors.forename: Jun
authors.initials: J
authors.lastname: Nakayama
mesh_terms: D000906:Antibodies / Q000276:immunology; D000918:Antibody Specificity; D002462:Cell Membrane / Q000378:metabolism*; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000096:biosynthesis; D004789:Enzyme Activation; D005964:Glucosyltransferases / Q000032:analysis / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D016480:Helicobacter pylori / Q000166:cytology* / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology; D042541:Intracellular Space / Q000201:enzymology / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D021381:Protein Transport
chemical_list: D000906:Antibodies; C027578:cholesteryl glucoside; D002784:Cholesterol; D005964:Glucosyltransferases; C514935:Hp0421 protein, Helicobacter pylori