JCB logo
PeproTech: Cell Culture Supplements
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 582K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Jakob, C. A.
Right arrow Articles by Aebi, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Jakob, C. A.
Right arrow Articles by Aebi, M.
Right arrowPubmed/NCBI databases
*Substance via MeSH
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

© The Rockefeller University Press, 0021-9525/1998//1223 $5.00
The Journal of Cell Biology, Volume 142, Number 5, , 1998 1223-1233

Articles

Degradation of Misfolded Endoplasmic Reticulum Glycoproteins in Saccharomyces cerevisiae Is Determined by a Specific Oligosaccharide Structure



Claude A. Jakob*, Patricie Burda{ddagger}, Jürgen Roth*, and Markus Aebi{ddagger}

* Division of Cell and Molecular Pathology, Department of Pathology, University of Zürich, CH-8091 Zürich, Switzerland; and {ddagger} Mikrobiologisches Institut, ETH Zürich, CH-8092 Zürich, Switzerland

In Saccharomyces cerevisiae, transfer of N-linked oligosaccharides is immediately followed by trimming of ER-localized glycosidases. We analyzed the influence of specific oligosaccharide structures for degradation of misfolded carboxypeptidase Y (CPY). By studying the trimming reactions in vivo, we found that removal of the terminal {alpha}1,2 glucose and the first {alpha}1,3 glucose by glucosidase I and glucosidase II respectively, occurred rapidly, whereas mannose cleavage by mannosidase I was slow. Transport and maturation of correctly folded CPY was not dependent on oligosaccharide structure. However, degradation of misfolded CPY was dependent on specific trimming steps. Degradation of misfolded CPY with N-linked oligosaccharides containing glucose residues was less efficient compared with misfolded CPY bearing the correctly trimmed Man8GlcNAc2 oligosaccharide. Reduced rate of degradation was mainly observed for mis- folded CPY bearing Man6GlcNAc2, Man7GlcNAc2 and Man9GlcNAc2 oligosaccharides, whereas Man8GlcNAc2 and, to a lesser extent, Man5GlcNAc2 oligosaccharides supported degradation. These results suggest a role for the Man8GlcNAc2 oligosaccharide in the degradation process. They may indicate the presence of a Man8GlcNAc2-binding lectin involved in targeting of misfolded glycoproteins to degradation in S. cerevisiae.

Key Words: protein degradation • endoplasmic reticulum • glycosylation • mannosidase • yeast

Abbreviations used in this paper: CPY, carboxypeptidase Y; CPY*, mutated, misfolded CPY; endo H, endoglycosidase H; LLO, lipid-linked oligosaccharides; NLO, N-linked oligosaccharides.

Address all correspondence to Markus Aebi, Mikrobiologisches Institut, ETH Zürich, Schmelzbergstrasse 7, CH-8092 Zürich, Switzerland. Tel.: 41 1 632 64 13. Fax: 41 1 632 11 48. E-mail: aebi{at}micro.biol.ethz.ch

2. Since the protein-bound oligosaccharides were released by Endo H cleavage, they are lacking one GlcNAc residue. For clarity, however, the NLO structure as found on protein is denoted.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents