Abstract
The heterotrimeric Sec61p complex is a major component of the protein- conducting channel of the endoplasmic reticulum (ER) membrane, associating with either ribosomes or the Sec62/63 complex to perform co- and posttranslational transport, respectively. We show by electron microscopy that purified mammalian and yeast Sec61p complexes in detergent form cylindrical oligomers with a diameter of ~85Å and a central pore of ~20 Å. Each oligomer contains 3-4 heterotrimers. Similar ring structures are seen in reconstituted proteoliposomes and native membranes. Oligomer formation by the reconstituted Sec61p complex is stimulated by its association with ribosomes or the Sec62/63p complex. We propose that these cylindrical oligomers represent protein-conducting channels of the ER, formed by ligands specific for co- and post-translational transport.
| Original language | English |
|---|---|
| Journal | Cell |
| Volume | 87 |
| Issue number | 4 |
| Pages (from-to) | 721-732 |
| Number of pages | 12 |
| ISSN | 0092-8674 |
| DOIs | |
| Publication status | Published - 15.01.1996 |
Funding
This work was supported by NIH grants to C. W. A. and T. A. R., the Fulbright Junior Research Program (D. H.), and a Rothschild Fellowship (D. H.). We thank Dr. J. Wall and M. Simon for collecting scanning-transmission electron microscopy images analyzed in this work, and Dr. E. Bullitt for help with the Brandeis mass-analysis programs. We thank M. Rolls, P. Stein, and E. Hartmann for critical reading of the manuscript.
Research Areas and Centers
- Academic Focus: Center for Infection and Inflammation Research (ZIEL)
