Skip Navigation



Glycobiology Advance Access published online on November 26, 2002
Glycobiology, doi:10.1093/glycob/cwg013
This Article
Right arrow Advance Access manuscript (PDF) Freely available
Right arrow All Versions of this Article:
13/3/159    most recent
cwg013v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Hardt, B.
Right arrow Articles by Bause, E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Hardt, B.
Right arrow Articles by Bause, E.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Submitted on May 17, 2002
Revised on September 17, 2002
Accepted on September 17, 2002

© 2002 Oxford University Press

ORIGINAL ARTICLES

(Arg)3 within the N-terminal domain of glucosidase I contains ER targeting information but is not required absolutely for ER localization

Birgit Hardt 1, Burga Kalz-Füller 1, Raquel Aparicio 1, Christof Völker 1, Ernst Bause 2*

1 Institut für Physiologische Chemie, Universität Bonn
2 1Institut für Physiologische Chemie, Universität Bonn

* To whom correspondence should be addressed. E-mail: bause{at}institut.physiochem.uni-bonn.de.

Abstract

Glucosidase I is an endoplasmic reticulum (ER) type II membrane enzyme which cleaves the distal {alpha}1,2-glucose of the asparagine-linked GlcNAc2-Man9-Glc3 precursor. In order to identify sequence motifs responsible for ER-localization, we prepared a protein chimaera by transferring the cytosolic and transmembrane domain of glucosidase I to the luminal domain of Golgi-Man9-mannosidase. The GIM9 hybrid was overexpressed in COS 1 cells as an ER-resident protein that displayed {alpha}1,2-mannosidase activity, excluding the possibility that the glucosidase I-specific domains interfere with folding of the Man9-mannosidase catalytic domain. After substitution of the arginines in position 7, 8 or 9 relative to the N-terminus by leucine, the GIM9 mutants were transported to the cell surface indicating that the (Arg)3 sequence functions as ER-targeting motif. Cell surface expression was also observed after substitution of Arg-7 or Arg-8 but not of Arg-9 in GIM9 by either lysine or histidine. Thus the side chain structure, including its positive charge, appears to be essential for signal function. Analysis of the N-linked glycans suggests that the (Arg)3 sequence mediates ER-localization through Golgi to ER retrograde transport.

Glucosidase I remained localized in the ER after truncation or mutation of the N-terminal (Arg)3 signal, in contrast to comparable GIM9 mutants. ER-localization was also observed with a M9GI chimaera consisting of the cytosolic and transmembrane domain of Man9-mannosidase and the glucosidase I catalytic domain. ER-specific targeting information must, therefore, be provided by sequence motifs contained within the glucosidase I luminal domain. This structural information appears to direct ER-localization by retention rather than by retrieval, as concluded from N-linked Man9-GlcNAc2 being the major glycan released from the wild-type enzyme.


Key words: Glucosidase I / type II membrane protein / arginine motif /Arg-Arg-Arg / endoplasmic reticulum / ER
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 Plant CellHome page
C. Saint-Jore-Dupas, A. Nebenfuhr, A. Boulaflous, M.-L. Follet-Gueye, C. Plasson, C. Hawes, A. Driouich, L. Faye, and V. Gomord
Plant N-Glycan Processing Enzymes Employ Different Targeting Mechanisms for Their Spatial Arrangement along the Secretory Pathway
PLANT CELL, November 1, 2006; 18(11): 3182 - 3200.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
C. Heine, B. Koch, S. Storch, A. Kohlschutter, D. N. Palmer, and T. Braulke
Defective Endoplasmic Reticulum-resident Membrane Protein CLN6 Affects Lysosomal Degradation of Endocytosed Arylsulfatase A
J. Biol. Chem., May 21, 2004; 279(21): 22347 - 22352.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.