A mammalian homolog of SEC61p and SECYp is associated with ribosomes and nascent polypeptides during translocation

@article{Grlich1992AMH,
  title={A mammalian homolog of SEC61p and SECYp is associated with ribosomes and nascent polypeptides during translocation},
  author={Dirk G{\"o}rlich and Siegfried Prehn and Enno Hartmann and Kai-Uwe Kalies and Tom A. Rapoport},
  journal={Cell},
  year={1992},
  volume={71},
  pages={489-503}
}
SEC61p is essential for protein translocation across the endoplasmic reticulum membrane of S. cerevisiae. We have found a mammalian homolog that shows more than 50% sequence identity with the yeast protein. Moreover, several regions of SEC61p have significant similarities with corresponding ones of SecYp of bacteria, indicating a strong evolutionary conservation of the mechanism of protein translocation. Mammalian Sec61p, like the yeast protein, is located in the immediate vicinity of nascent… 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
Evolutionary conservation of components of the protein translocation complex
TLDR
The sequences of the β- and γ-subunits of the mammalian Sec61p complex are determined and seem to be key components of the protein translocation apparatus in all classes of organisms. Expand
The Sec61 complex is essential for the insertion of proteins into the membrane of the endoplasmic reticulum
TLDR
The view that Sec61α is a major component of the ER translocation site and promotes both the insertion of membrane proteins and the translocation of secretory proteins is supported. 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
Posttranslational protein transport in yeast reconstituted with a purified complex of Sec proteins and Kar2p
TLDR
It is hypothesize that distinct membrane protein complexes function in co- and posttranslational translocation pathways. Expand
Determination of the Transmembrane Topology of Yeast Sec61p, an Essential Component of the Endoplasmic Reticulum Translocation Complex*
TLDR
The transmembrane topology of Sec61p is determined using a combination of C-terminal reporter-domain fusions and the in situ digestion of specifically inserted factor Xa protease cleavage sites to provide evidence for complex intramolecular interactions in which these weakly hydrophobic domains require C- terminal sequences for their correct topogenesis. Expand
Alignment of conduits for the nascent polypeptide chain in the ribosome-Sec61 complex.
TLDR
Cryo-electron microscopy of the ribosome-Sec61 complex and a three-dimensional reconstruction showed that the Sec61 oligomer is attached to the large ribosomal subunit by a single connection, strongly suggesting that both structures function together in the translocation of proteins across the endoplasmic reticulum membrane. 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
A SecY Homolog in Arabidopsis thaliana
TLDR
The nucleotide sequence of a full-length cDNA encoding a homolog of SecY from Arabidopsis thaliana is reported, and the predicted protein of 551 residues includes an amino-terminal extension of approximately 120 residues when compared with other SecY proteins. Expand
Sec62p, a component of the endoplasmic reticulum protein translocation machinery, contains multiple binding sites for the Sec-complex.
TLDR
SEC62 encodes an essential component of the Sec-complex that is responsible for posttranslational protein translocation across the membrane of the endoplasmic reticulum in Saccharomyces cerevisiae and it is shown that Sec62p binds via its cytosolic N- and C-terminal domains to theSec-complex. Expand
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References

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TLDR
These results confirm previous predictions, based upon genetic interactions between the SEC genes, that Sec61, Sec62 and Sec63 act together to facilitate protein translocation into the ER. Expand
Yeast Sec proteins interact with polypeptides traversing the endoplasmic reticulum membrane
We show by photocross-linking that nascent secretory proteins, during their passage through the endoplasmic reticulum membrane of S. cerevisiae, are in physical contact with Sec61p and Sec62p, twoExpand
Topology analysis of the SecY protein, an integral membrane protein involved in protein export in Escherichia coli.
TLDR
The results suggest that SecY contains 10 transmembrane segments, five periplasmically exposed parts, and six cytoplasmic regions including the amino‐ and carboxyterminal regions. Expand
Sec61p and BiP directly facilitate polypeptide translocation into the ER
TLDR
It is suggested that Sec61p is directly involved in translocation and that BiP acts at two stages of the translocation cycle. Expand
SEC62 encodes a putative membrane protein required for protein translocation into the yeast endoplasmic reticulum
TLDR
A potential membrane location for the SEC62 gene product is supported by evaluation of the molecular clone and DNA sequence analysis reveals a 32- kD protein with no obvious NH2-terminal signal sequence but with two domains of sufficient length and hydrophobicity to span a lipid bilayer. Expand
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TLDR
Cloned the secY gene of Lactococcus lactis is found to be similar in length to the previously determined SecY proteins of Escherichia coli, Bacillus subtilis and Mycoplasma capricolum, and 90 conserved amino acid residues are revealed. Expand
The purified E. coli integral membrane protein SecY E is sufficient for reconstitution of SecA-dependent precursor protein translocation
TLDR
The isolation of the SecY/E protein, the integral membrane protein component of the E. coli preprotein translocase, is reported, which consists of SecY, SecE, and an additional polypeptide. Expand
The signal sequence of nascent preprolactin interacts with the 54K polypeptide of the signal recognition particle
TLDR
This work shows for the first time a direct interaction between the signal sequence of a secretory protein and a component of SRP, the 54K polypeptide (relative molecular mass (Mr) 54,000), achieved by means of a new method of affinity labelling which involves the translational incorporation of an amino acid, carrying a photoreactive group, into nascentpolypeptides. Expand
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TLDR
The DNA sequence of the two genes along with alkaline phosphatase fusion analysis indicates that they code for integral proteins of the cytoplasmic membrane, suggesting that these two proteins may form a complex in the membrane which acts at late steps in the export process. Expand
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TLDR
The chimeric membrane protein allows the selection of more restrictive sec mutations rather than defining genes that are required only for membrane protein assembly. Expand
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