Interactions between Sec Complex and Prepro-α-Factor during Posttranslational Protein Transport into the Endoplasmic Reticulum
| Autor: | Colin J. Stirling, Barrie Wilkinson, Tom A. Rapoport, Kathrin Plath |
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| Rok vydání: | 2004 |
| Předmět: |
Signal peptide
Sec61 Saccharomyces cerevisiae Proteins Saccharomyces cerevisiae Protein Sorting Signals Biology Endoplasmic Reticulum Cloning Molecular Protein Precursors Molecular Biology Endoplasmic reticulum membrane Endoplasmic reticulum Membrane Proteins Membrane Transport Proteins Biological Transport STIM1 Intracellular Membranes Articles Cell Biology Transmembrane protein Cell Compartmentation Protein Structure Tertiary Transport protein Cell biology A-site Protein Biosynthesis Mutation Mating Factor Peptides Protein Processing Post-Translational SEC Translocation Channels Protein Binding |
| Zdroj: | Molecular Biology of the Cell. 15:1-10 |
| ISSN: | 1939-4586 1059-1524 |
| Popis: | Posttranslational translocation of prepro-α-factor (ppαF) across the yeast endoplasmic reticulum membrane begins with the binding of the signal sequence to the Sec complex, a membrane component consisting of the trimeric Sec61p complex and the tetrameric Sec62p/63p complex. We show by photo-cross-linking that the signal sequence is bound directly to a site where it contacts simultaneously Sec61p and Sec62p, suggesting that there is a single signal sequence recognition step. We found no evidence for the simultaneous contact of the signal sequence with two Sec61p molecules. To identify transmembrane segments of Sec61p that line the actual translocation pore, a late translocation intermediate of ppαF was generated with photoreactive probes incorporated into the mature portion of the polypeptide. Cross-linking to multiple regions of Sec61p was observed. In contrast to the signal sequence, neighboring positions of the mature portion of ppαF had similar interactions with Sec61p. These data suggest that the channel pore is lined by several transmembrane segments, which have no significant affinity for the translocating polypeptide chain. |
| Databáze: | OpenAIRE |
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