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Updated: Jul 15, 2026

Budding Yeast Protein Extraction and Purification for the Study of Function, Interactions, and Post-translational Modifications
Published on: October 30, 2013
Posttranslational protein transport in yeast reconstituted with a purified complex of Sec proteins and Kar2p
S Panzner1, L Dreier, E Hartmann
1Max-Delbrück-Center for Molecular Medicine, Berlin-Buch, Federal Republic of Germany.
Abstract:
We have reproduced the posttranslational mode of protein translocation across the endoplasmic reticulum membrane with reconstituted proteoliposomes containing a purified complex of seven yeast proteins. This Sec complex includes a heterotrimeric Sec61p complex, homologous to that in mammals, as well as all other membrane proteins found in genetic screens for translocation components. Efficient posttranslational translocation also requires the addition of lumenal Kar2p (BiP) and ATP. The trimeric Sec61p complex also exists as a separate entity that, in contrast with the large Sec complex, is associated with membrane-bound ribosomes. We therefore hypothesize that distinct membrane protein complexes function in co- and posttranslational translocation pathways.
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