title: Biogenesis of vacuolar membrane glycoproteins of yeast Saccharomyces cerevisiae.
abstract: To investigate the biogenesis of the yeast vacuole, we have sought novel marker proteins localized to the vacuolar membrane. Glycoproteins were prepared from vacuolar membrane vesicles by concanavalin A-Sepharose column chromatography and used to raise monoclonal antibodies. The antibodies obtained recognize several vacuolar proteins that have N-linked oligosaccharide chains. A set of the antibodies reacts with a vacuolar glycoprotein with a major molecular species of 72 kDa (vgp72), which appears to associate peripherally with the vacuolar membrane. The biosynthesis of vgp72 has been examined in detail by pulse-chase experiments and by analyses using various secretory mutants (sec18, sec7, and sec1) and a vacuolar protease mutant (pep4). vgp72 first appears in the endoplasmic reticulum as a 74-kDa species and is quickly modified in the Golgi apparatus to two distinct species: a 79-kDa form, and a heterogeneously glycosylated form (90-150 kDa). Subsequently, both species are proteolytically processed in the vacuole giving rise to a 72-kDa species as well as heavily glycosylated form. Thus, the biogenesis of vgp72 utilizes the early part of the secretory pathway as is the case of vacuolar soluble enzymes. A unique feature is that two species that are different in the extent of glycosylation appear to follow the same destination to the vacuolar membrane.
authors.affiliation: Department of Biology, Faculty of Science, University of Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nishikawa
authors.forename: N
authors.initials: N
authors.lastname: Umemoto
authors.forename: Y
authors.initials: Y
authors.lastname: Ohsumi
authors.forename: A
authors.initials: A
authors.lastname: Nakano
authors.forename: Y
authors.initials: Y
authors.lastname: Anraku
mesh_terms: D000118:Acetylglucosaminidase; D000911:Antibodies, Monoclonal; D002458:Cell Fractionation; D002499:Centrifugation, Density Gradient; D005455:Fluorescent Antibody Technique; D005838:Genotype; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000302:isolation & purification; D008970:Molecular Weight; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D014617:Vacuoles / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D000911:Antibodies, Monoclonal; D008562:Membrane Glycoproteins; D000118:Acetylglucosaminidase; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase