Published online October 22, 2007
doi:10.1083/jcb.200704142
The Journal of Cell Biology, Vol. 179, No. 2, 209-217
The Rockefeller University Press, 0021-9525 $30.00
© 2007 Michelsen et al.
Novel cargo-binding site in the ß and
subunits of coatomer
Kai Michelsen1,
Volker Schmid1,
Jutta Metz1,
Katja Heusser1,
Urban Liebel2,
Torsten Schwede3,
Anne Spang4, and
Blanche Schwappach1
1 Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
2 European Molecular Biology Laboratory (EMBL), Cell Biology Cell Biophysics Unit, D-69117 Heidelberg, Germany
3 Swiss Institute of Bioinformatics, Biozentrum, University of Basel, CH-4056 Basel, Switzerland
4 Growth & Development, Biozentrum, University of Basel, CH-4056 Basel, Switzerland
Correspondence to Blanche Schwappach: b.schwappach{at}zmbh.uni-heidelberg.de
Arginine (R)-based ER localization signals are sorting motifs that confer transient ER localization to unassembled subunits of multimeric membrane proteins. The COPI vesicle coat binds R-based signals but the molecular details remain unknown. Here, we use reporter membrane proteins based on the proteolipid Pmp2 fused to GFP and allele swapping of COPI subunits to map the recognition site for R-based signals. We show that two highly conserved stretches—in the ß- and
-COPI subunits—are required to maintain Pmp2GFP reporters exposing R-based signals in the ER. Combining a deletion of 21 residues in
-COP together with the mutation of three residues in ß-COP gave rise to a COPI coat that had lost its ability to recognize R-based signals, whilst the recognition of C-terminal di-lysine signals remained unimpaired. A homology model of the COPI trunk domain illustrates the recognition of R-based signals by COPI.
U. Liebel's present address is Institute of Toxicology and Genetics, Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany.
Abbreviations used in this paper: AD, activation domain; BD, binding domain.

CiteULike
Complore
Connotea
Del.icio.us
Digg
Reddit
Technorati What's this?
This article has been cited by other articles:
-
Uemura, S., Yoshida, S., Shishido, F., Inokuchi, J.-i.
(2009). The Cytoplasmic Tail of GM3 Synthase Defines Its Subcellular Localization, Stability, and In Vivo Activity. Mol. Biol. Cell
20: 3088-3100
[Abstract]
[Full Text]
-
Zuzarte, M., Heusser, K., Renigunta, V., Schlichthorl, G., Rinne, S., Wischmeyer, E., Daut, J., Schwappach, B., Preisig-Muller, R.
(2009). Intracellular traffic of the K+ channels TASK-1 and TASK-3: role of N- and C-terminal sorting signals and interaction with 14-3-3 proteins. J. Physiol.
587: 929-952
[Abstract]
[Full Text]
-
Burman, J. L., Bourbonniere, L., Philie, J., Stroh, T., Dejgaard, S. Y., Presley, J. F., McPherson, P. S.
(2008). Scyl1, Mutated in a Recessive Form of Spinocerebellar Neurodegeneration, Regulates COPI-mediated Retrograde Traffic. J. Biol. Chem.
283: 22774-22786
[Abstract]
[Full Text]