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Lumenal proteins of the mammalian endoplasmic reticulum are required to complete protein translocation.

Publication ,  Journal Article
Nicchitta, CV; Blobel, G
Published in: Cell
June 4, 1993

The role of the lumenal contents (reticuloplasm) of the endoplasmic reticulum (ER) in protein translocation was determined by in vitro analysis. Depletion of the reticuloplasm from mammalian rough microsomes revealed two distinct stages of the translocation reaction. The first stage, translocation up to and including signal peptide cleavage, was insensitive to the loss of the reticuloplasm, whereas the second stage, net transfer of the nascent chain into the ER lumen, was reticuloplasm dependent. In reticuloplasm-depleted membranes, signal-cleaved and glycosylated translocation intermediates were observed to transit free from the translocation channel to the cis, or cytoplasmic, side of the membrane. This translocation defect was complemented by reconstitution of lumenal proteins into depleted membranes. We propose that lumenal proteins are necessary for unidirectional protein translocation in mammalian ER.

Duke Scholars

Published In

Cell

DOI

ISSN

0092-8674

Publication Date

June 4, 1993

Volume

73

Issue

5

Start / End Page

989 / 998

Location

United States

Related Subject Headings

  • Protein Sorting Signals
  • Protein Precursors
  • Prolactin
  • Pancreas
  • Oligosaccharides
  • Microsomes
  • In Vitro Techniques
  • Hydrogen-Ion Concentration
  • Endoplasmic Reticulum
  • Dogs
 

Citation

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Nicchitta, C. V., & Blobel, G. (1993). Lumenal proteins of the mammalian endoplasmic reticulum are required to complete protein translocation. Cell, 73(5), 989–998. https://doi.org/10.1016/0092-8674(93)90276-v
Nicchitta, C. V., and G. Blobel. “Lumenal proteins of the mammalian endoplasmic reticulum are required to complete protein translocation.Cell 73, no. 5 (June 4, 1993): 989–98. https://doi.org/10.1016/0092-8674(93)90276-v.
Nicchitta, C. V., and G. Blobel. “Lumenal proteins of the mammalian endoplasmic reticulum are required to complete protein translocation.Cell, vol. 73, no. 5, June 1993, pp. 989–98. Pubmed, doi:10.1016/0092-8674(93)90276-v.
Journal cover image

Published In

Cell

DOI

ISSN

0092-8674

Publication Date

June 4, 1993

Volume

73

Issue

5

Start / End Page

989 / 998

Location

United States

Related Subject Headings

  • Protein Sorting Signals
  • Protein Precursors
  • Prolactin
  • Pancreas
  • Oligosaccharides
  • Microsomes
  • In Vitro Techniques
  • Hydrogen-Ion Concentration
  • Endoplasmic Reticulum
  • Dogs