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, 602K)
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 Shamu, C. E.
Right arrow Articles by Ploegh, H. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Shamu, C. E.
Right arrow Articles by Ploegh, H. L.
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
© The Rockefeller University Press, 0021-9525/1999/10/45/ $5.00
The Journal of Cell Biology, Volume 147, Number 1, October 4, 1999 45-58


Original Article

The Pathway of US11-dependent Degradation of MHC Class I Heavy Chains Involves a Ubiquitin-conjugated Intermediate

Caroline E. Shamua, Craig M. Storyb, Tom A. Rapoporta,c, and Hidde L. Ploeghb
a Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
b Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115
c Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115

Correspondence to: Caroline E. Shamu, Department of Cell Biology, Harvard Medical School, 240 Longwood Ave., Boston, MA 02115. Tel:(617) 432-1611 Fax:(617) 432-1190 E-mail:shamu{at}bcmp.med.harvard.edu.

The human cytomegalovirus protein, US11, initiates the destruction of MHC class I heavy chains by targeting them for dislocation from the ER to the cytosol and subsequent degradation by the proteasome. We report the development of a permeabilized cell system that recapitulates US11-dependent degradation of class I heavy chains. We have used this system, in combination with experiments in intact cells, to identify and order intermediates in the US11-dependent degradation pathway. We find that heavy chains are ubiquitinated before they are degraded. Ubiquitination of the cytosolic tail of heavy chain is not required for its dislocation and degradation, suggesting that ubiquitination occurs after at least part of the heavy chain has been dislocated from the ER. Thus, ubiquitination of the heavy chain does not appear to be the signal to start dislocation. Ubiquitinated heavy chains are associated with membrane fractions, suggesting that ubiquitination occurs while the heavy chain is still bound to the ER membrane. Our results support a model in which US11 co-opts the quality control process by which the cell destroys misfolded ER proteins in order to specifically degrade MHC class I heavy chains.

Key Words: ubiquitin, US11, dislocation, endoplasmic reticulum, quality control


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 Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:



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