Posttranslational protein transport in yeast reconstituted with a purified complex of Sec proteins and Kar2p

@article{Panzner1995PosttranslationalPT,
  title={Posttranslational protein transport in yeast reconstituted with a purified complex of Sec proteins and Kar2p},
  author={S. Panzner and L. Dreier and E. Hartmann and S. Kostka and T. Rapoport},
  journal={Cell},
  year={1995},
  volume={81},
  pages={561-570}
}
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… Expand
Protein transport by purified yeast Sec complex and Kar2p without membranes.
TLDR
A translocation substrate was initially bound to the cytosolic face of the purified Sec complex in a signal-sequence-dependent but Kar2p- and nucleotide-independent manner and moved through a channel formed by the Sec complex and was released at the lumenal end. Expand
Oligomeric Rings of the Sec61p Complex Induced by Ligands Required for Protein Translocation
TLDR
It is proposed that these cylindrical oligomers represent protein-conducting channels of the ER, formed by ligands specific for co- and posttranslational transport. Expand
Mammalian Sec61 Is Associated with Sec62 and Sec63*
TLDR
The existence of ribosome-free mammalian Sec61 complexes that associate with two ubiquitous proteins of the ER membrane that are named Sec62 and Sec63, respectively are reported here. Expand
The bacterial SecY/E translocation complex forms channel-like structures similar to those of the eukaryotic Sec61p complex.
TLDR
This work purifies a translocationally active complex of the two subunits, SecY and SecE, from Bacillus subtilis that forms ring structures in detergent solution and in intact lipid bilayers, often with a quasi-pentagonal appearance in projection. Expand
The Sec62–Sec63 translocon facilitates translocation of the C-terminus of membrane proteins
TLDR
There is an unappreciated function of the Sec62–Sec63 translocon in regulating topogenesis of membrane proteins in the eukaryotic cell, according to systematic analysis of single and multi-spanning membrane proteins. Expand
The structure of the Sec complex and the problem of protein translocation
TLDR
Structural findings, combined with previous genetic and biochemical studies, have helped to describe how the passage of proteins through the membrane might occur, but several points of uncertainty remain. Expand
Protein kinase CK2 phosphorylates Sec63p to stimulate the assembly of the endoplasmic reticulum protein translocation apparatus
TLDR
Findings show that phosphorylation of Sec63p is required for tightly recruiting the putative signal-sequence-binding subunit Sec62p to the Sec complex. Expand
Structure of the posttranslational Sec protein-translocation channel complex from yeast
TLDR
The structure shows that Sec63 tightly associates with Sec61 through interactions in cytosolic, transmembrane, and ER-luminal domains, prying open Sec61’s lateral gate and translocation pore and thus activating the channel for substrate engagement, and provides mechanistic insights into eukaryotic posttranslational protein translocation. Expand
Proper insertion and topogenesis of membrane proteins in the ER depend on Sec63.
TLDR
It is found that proper sorting of single- and double-pass membrane proteins was severely impaired in addition to post-translational translocation precursor in the sec63_ΔN39 mutant strain, and Sec63 is essential on insertion of membrane proteins. Expand
The Brl Domain in Sec63p Is Required for Assembly of Functional Endoplasmic Reticulum Translocons*
TLDR
Using a series of mutant alleles, it is demonstrated that a conserved Brl (Brr2-like) domain in the COOH-terminal cytosolic region of Sec63p is essential for function both in vivo and in vitro. Expand
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