title: Distinct functional units of the Golgi complex in Drosophila cells.
abstract: A striking variety of glycosylation occur in the Golgi complex in a protein-specific manner, but how this diversity and specificity are achieved remains unclear. Here we show that stacked fragments (units) of the Golgi complex dispersed in Drosophila imaginal disk cells are functionally diverse. The UDP-sugar transporter FRINGE-CONNECTION (FRC) is localized to a subset of the Golgi units distinct from those harboring SULFATELESS (SFL), which modifies glucosaminoglycans (GAGs), and from those harboring the protease RHOMBOID (RHO), which processes the glycoprotein SPITZ (SPI). Whereas the glycosylation and function of NOTCH are affected in imaginal disks of frc mutants, those of SPI and of GAG core proteins are not, even though FRC transports a broad range of glycosylation substrates, suggesting that Golgi units containing FRC and those containing SFL or RHO are functionally separable. Distinct Golgi units containing FRC and RHO in embryos could also be separated biochemically by immunoisolation techniques. We also show that Tn-antigen glycan is localized only in a subset of the Golgi units distributed basally in a polarized cell. We propose that the different localizations among distinct Golgi units of molecules involved in glycosylation underlie the diversity of glycan modification.
authors.affiliation: Mitsubishi-Kagaku Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo 194-8511, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yano
authors.forename: Miki
authors.initials: M
authors.lastname: Yamamoto-Hino
authors.forename: Masato
authors.initials: M
authors.lastname: Abe
authors.forename: Reiko
authors.initials: R
authors.lastname: Kuwahara
authors.forename: Shuka
authors.initials: S
authors.lastname: Haraguchi
authors.forename: Isamu
authors.initials: I
authors.lastname: Kusaka
authors.forename: Wakae
authors.initials: W
authors.lastname: Awano
authors.forename: Akiko
authors.initials: A
authors.lastname: Kinoshita-Toyoda
authors.forename: Hidenao
authors.initials: H
authors.lastname: Toyoda
authors.forename: Satoshi
authors.initials: S
authors.lastname: Goto
mesh_terms: D000818:Animals; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D021381:Protein Transport / Q000502:physiology
chemical_list: D029721:Drosophila Proteins; D011134:Polysaccharides