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Updated: Jul 12, 2026
09:42
Using SecM Arrest Sequence as a Tool to Isolate Ribosome Bound Polypeptides
Published on: June 19, 2012
A posttargeting signal sequence recognition event in the endoplasmic reticulum membrane
1Max Delbrück Center for Molecular Medicine, Berlin-Buch, Federal Republic of Germany.
Cell
|July 28, 1995
Summary
Secretory proteins use two signal recognition events for transport across the endoplasmic reticulum (ER) membrane. The signal recognition particle (SRP) and Sec61p complex are essential for this cotranslational process.
Area of Science:
- Molecular Biology
- Cell Biology
- Protein Transport
Background:
- The endoplasmic reticulum (ER) membrane is a critical barrier controlling protein localization within eukaryotic cells.
- Secretory proteins must efficiently and accurately cross the ER membrane to reach their destinations.
Purpose of the Study:
- To investigate the early stages of cotranslational transport of secretory proteins across the mammalian ER membrane.
- To elucidate the roles of the signal recognition particle (SRP) and Sec61p complex in protein translocation.
Main Methods:
- Analysis of the cotranslational transport of preprolactin.
- Investigating signal sequence recognition events in the cytosol and ER membrane.
Main Results:
- The signal sequence of preprolactin is recognized by SRP in the cytosol.
- A second signal sequence recognition event occurs within the ER membrane, requiring the Sec61p complex.
- This leads to a stable interaction between the ribosome-nascent chain complex and Sec61p, enabling translocation.
Conclusions:
- Protein translocation across the ER membrane involves at least two distinct signal recognition events.
- The Sec61p complex is essential and sufficient for the second signal recognition step and productive insertion into the translocation site.
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