Posttranslational Protein Translocation Across the Membrane of the Endoplasmic Reticulum
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Tom A. Rapoport
Abstract
Posttranslational protein translocation across the membrane of the endoplasmic reticulum is mediated by the Sec complex. This complex includes a transmembrane channel formed by multiple copies of the Sec61 protein. Translocation of a polypeptide begins when the signal sequence binds at a specific site within the channel. Binding results in the insertion of the substrate into the channel, possibly as a loop with a small segment exposed to the lumen. While bound, the signal sequence is in contact with both protein components of the channel and the lipid of the membrane. Subsequent movement of the polypeptide through the channel occurs when BiP molecules interact transiently with a luminal domain of the Sec complex, hydrolyze ATP, and bind to the substrate. Bound BiP promotes translocation by preventing the substrate from diffusing backwards through the channel, and thus acts as a molecular ratchet.
Copyright © 1999 by Walter de Gruyter GmbH & Co. KG
Articles in the same Issue
- Editors Note
- Walter Neupert: Spellbound by Mitochondria
- Posttranslational Protein Translocation Across the Membrane of the Endoplasmic Reticulum
- Import of Carrier Proteins into Mitochondria
- The Essential Role of Mitochondria in the Biogenesis of Cellular Iron-Sulfur Proteins
- Mitochondrial Iron Metabolism in the Yeast Saccharomyces cerevisiae
- A Scj1p Homolog and Folding Catalysts Present in Dog Pancreas Microsomes
- The Import Pathway of Human and Thermoplasma 20S Proteasomes into HeLa Cell Nuclei Is Different from That of Classical NLS-Bearing Proteins
- Role of p52 (NF-kappaB2) in LPS Tolerance in a Human B Cell Line
- SHP1 Protein Tyrosine Phosphatase Negatively Modulates Erythroid Differentiation and Suppression of Apoptosis in J2E Erythroleukemic Cells
- Comparative Cleavage Sites within the Reactive-Site Loop of Native and Oxidized α1-Proteinase Inhibitor by Selected Bacterial Proteinases
- A High Affinity Binding Site for the Polypyrimidine Tract Binding Protein (PTB) Is Located in the 5'-Untranslated Region of the Rat Proteinase α1-Inhibitor 3 Variant I Gene
- Defining the Location and Function of Domains of McrB by Deletion Mutagenesis
- Disruption of the Gene for Hsp30, an α-Crystallin-Related Heat Shock Protein of Neurospora crassa, Causes Defects in Import of Proteins into Mitochondria
- Cloning, Purification and Characterisation of Cystathionine γ-Synthase from Nicotiana tabacum
- Isolation and Characterization of Viridin, a New 65 kDa Antifungal Protein from the Mould Trichoderma viride
- The T-Knot Motif Revisited
Articles in the same Issue
- Editors Note
- Walter Neupert: Spellbound by Mitochondria
- Posttranslational Protein Translocation Across the Membrane of the Endoplasmic Reticulum
- Import of Carrier Proteins into Mitochondria
- The Essential Role of Mitochondria in the Biogenesis of Cellular Iron-Sulfur Proteins
- Mitochondrial Iron Metabolism in the Yeast Saccharomyces cerevisiae
- A Scj1p Homolog and Folding Catalysts Present in Dog Pancreas Microsomes
- The Import Pathway of Human and Thermoplasma 20S Proteasomes into HeLa Cell Nuclei Is Different from That of Classical NLS-Bearing Proteins
- Role of p52 (NF-kappaB2) in LPS Tolerance in a Human B Cell Line
- SHP1 Protein Tyrosine Phosphatase Negatively Modulates Erythroid Differentiation and Suppression of Apoptosis in J2E Erythroleukemic Cells
- Comparative Cleavage Sites within the Reactive-Site Loop of Native and Oxidized α1-Proteinase Inhibitor by Selected Bacterial Proteinases
- A High Affinity Binding Site for the Polypyrimidine Tract Binding Protein (PTB) Is Located in the 5'-Untranslated Region of the Rat Proteinase α1-Inhibitor 3 Variant I Gene
- Defining the Location and Function of Domains of McrB by Deletion Mutagenesis
- Disruption of the Gene for Hsp30, an α-Crystallin-Related Heat Shock Protein of Neurospora crassa, Causes Defects in Import of Proteins into Mitochondria
- Cloning, Purification and Characterisation of Cystathionine γ-Synthase from Nicotiana tabacum
- Isolation and Characterization of Viridin, a New 65 kDa Antifungal Protein from the Mould Trichoderma viride
- The T-Knot Motif Revisited
