Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 1995 Feb;128(4):525-36.
doi: 10.1083/jcb.128.4.525.

The alpha subunit of the Saccharomyces cerevisiae oligosaccharyltransferase complex is essential for vegetative growth of yeast and is homologous to mammalian ribophorin I

S Silberstein  1 , P G Collins, D J Kelleher, P J Rapiejko, R Gilmore
Affiliations
Comparative Study

The alpha subunit of the Saccharomyces cerevisiae oligosaccharyltransferase complex is essential for vegetative growth of yeast and is homologous to mammalian ribophorin I

S Silberstein et al. J Cell Biol. 1995 Feb.

Abstract

Oligosaccharyltransferase mediates the transfer of a preassembled high mannose oligosaccharide from a lipid-linked oligosaccharide donor to consensus glycosylation acceptor sites in newly synthesized proteins in the lumen of the rough endoplasmic reticulum. The Saccharomyces cerevisiae oligosaccharyltransferase is an oligomeric complex composed of six nonidentical subunits (alpha-zeta), two of which are glycoproteins (alpha and beta). The beta and delta subunits of the oligosaccharyltransferase are encoded by the WBP1 and SWP1 genes. Here we describe the functional characterization of the OST1 gene that encodes the alpha subunit of the oligosaccharyltransferase. Protein sequence analysis revealed a significant sequence identity between the Saccharomyces cerevisiae Ost1 protein and ribophorin I, a previously identified subunit of the mammalian oligosaccharyltransferase. A disruption of the OST1 locus was not tolerated in haploid yeast showing that expression of the Ost1 protein is essential for vegetative growth of yeast. An analysis of a series of conditional ost1 mutants demonstrated that defects in the Ost1 protein cause pleiotropic underglycosylation of soluble and membrane-bound glycoproteins at both the permissive and restrictive growth temperatures. Microsomal membranes isolated from ost1 mutant yeast showed marked reductions in the in vitro transfer of high mannose oligosaccharide from exogenous lipid-linked oligosaccharide to a glycosylation site acceptor tripeptide. Microsomal membranes isolated from the ost1 mutants contained elevated amounts of the Kar2 stress-response protein.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463-7 - PubMed
    1. J Mol Biol. 1990 Oct 5;215(3):403-10 - PubMed
    1. J Biol Chem. 1979 May 10;254(9):3600-7 - PubMed
    1. J Biol Chem. 1980 Jun 25;255(12):5986-91 - PubMed
    1. J Biol Chem. 1982 Mar 25;257(6):3203-10 - PubMed

Publication types

MeSH terms

Associated data