title: AtUTr2 is an Arabidopsis thaliana nucleotide sugar transporter located in the Golgi apparatus capable of transporting UDP-galactose.
abstract: The synthesis of noncellulosic polysaccharides and glycoproteins in the plant cell Golgi apparatus requires UDP-galactose as a substrate. We have cloned and characterized a nucleotide sugar transporter from Arabidopsis thaliana (L.) Heynh. named AtUTr2. Expression in tobacco and Saccharomyces cerevisiae and subsequent biochemical characterization indicate that AtUTr2 transports UDP-galactose, but not UDP-glucose, UDP-N-acetyl glucosamine, UDP-xylose, UDP-glucuronic acid, GDP-fucose or GDP-mannose. Experiments expressing an AtUTr2-GFP fusion protein in onion epidermal cells suggest that AtUTr2 is located in the Golgi apparatus. Finally, northern analysis indicates that the AtUTr2 transcript was more abundant in roots and calli although it was also present in other Arabidopsis organs but at lower levels. Therefore, AtUTr2 is a nucleotide sugar transporter capable of transporting UDP-galactose that may play an important role in the synthesis of galactose-containing glycoconjugates in Arabidopsis.
authors.affiliation: Plant Cell Biology Millennium Nucleus, Department of Biology, Faculty of Science, University of Chile and Centre of Plant Biotechnology, University Andrés Bello, Republica 217, Santiago, Chile. aorellana@unab.cl
authors.forename: Lorena
authors.initials: L
authors.lastname: Norambuena
authors.forename: Ricardo
authors.initials: R
authors.lastname: Nilo
authors.forename: Michael
authors.initials: M
authors.lastname: Handford
authors.forename: Francisca
authors.initials: F
authors.lastname: Reyes
authors.forename: Lorena
authors.initials: L
authors.lastname: Marchant
authors.forename: Lee
authors.initials: L
authors.lastname: Meisel
authors.forename: Ariel
authors.initials: A
authors.lastname: Orellana
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001483:Base Sequence; D018506:Gene Expression Regulation, Plant; D006056:Golgi Apparatus / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013379:Substrate Specificity; D014026:Nicotiana / Q000235:genetics; D014531:Uridine Diphosphate Galactose / Q000378:metabolism*; D014532:Uridine Diphosphate Glucose / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; C506892:UTr2 protein, Arabidopsis; D014531:Uridine Diphosphate Galactose; D014532:Uridine Diphosphate Glucose