Evidence for a UDP-glucose transporter in Golgi apparatus-derived vesicles from pea and its possible role in polysaccharide biosynthesis

Patricia Muñoz, Lorena Norambuena, Ariel Orellana

Research output: Contribution to journalArticlepeer-review

65 Citations (Scopus)

Abstract

The Golgi apparatus in plant cells is involved in hemicellulose and pectin biosynthesis. While it is known thai glucan synthase I is responsible for the formation of β-1-4-linked glucose (Glc) polymers and uses UDP-Glc as a substrate, very little is known about the topography of reactions leading to the biosynthesis of polysaccharides in this organelle. We isolated from pea (Pisum sativum) stems a fraction highly enriched in Golgi apparatus- derived vesicles thai are sealed and have the same topographical orientation that the membranes have in vivo. Using these vesicles and UDP-Glc, we reconstituted polysaccharide biosynthesis in vitro and found evidence for a luminal location of the active site of glucan synthase I. In addition, we identified a UDP-Glc transport activity, which is likely to be involved in supplying substrate for glucan synthase I. We found that UDP-Glc transport is protein mediated. Moreover, our results suggest that UDP-Glc transport is coupled to the exit of a luminal uridine-containing nucleotide via an antiporter mechanism. We suggest that UDP-Glc is transported into the lumen of Golgi and that Glc is transferred to a polysaccharide chain, whereas the nucleotide moiety leaves the vesicle by an antiporter mechanism.

Original languageEnglish
Pages (from-to)1585-1594
Number of pages10
JournalPlant Physiology
Volume112
Issue number4
DOIs
Publication statusPublished - Dec 1996

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

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