Uridine diphosphate-glucose transport into the endoplasmic reticulum of Saccharomyces cerevisiae: in vivo and in vitro evidence.

ABSTRACT: It has been proposed that synthesis of beta-1,6-glucan, one of Saccharomyces cerevisiae cell wall components, is initiated by a uridine diphosphate (UDP)-glucose-dependent reaction in the lumen of the endoplasmic reticulum (ER). Because this sugar nucleotide is not synthesized in the lumen of the ER, we have examined whether or not UDP-glucose can be transported across the ER membrane. We have detected transport of this sugar nucleotide into the ER in vivo and into ER-containing microsomes in vitro. Experiments with ER-containing microsomes showed that transport of UDP-glucose was temperature dependent and saturable with an apparent Km of 46 microM and a Vmax of 200 pmol/mg protein/3 min. Transport was substrate specific because UDP-N-acetylglucosamine did not enter these vesicles. Demonst

SUBMITTER: Castro O 

PROVIDER: S-EPMC25230 | biostudies-literature | 1999 Apr

REPOSITORIES: biostudies-literature