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Protein transport across the ER membrane
1Zentralinstitut für Molekularbiologie, Akademie der Wissenschaften, Berlin-Buch, DDR.
Trends in Biochemical Sciences
|September 1, 1990
Summary
This review details protein transport initiation at the endoplasmic reticulum (ER) membrane. It highlights signal sequence recognition by the signal recognition particle (SRP) and suggests a translocation complex involving signal sequence receptor protein (SSR) for polypeptide transfer.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Protein transport across the endoplasmic reticulum (ER) membrane is crucial for cellular function.
- The process involves distinct phases: initiation/targeting and polypeptide transfer.
- The mechanism of polypeptide transfer through the ER membrane remains largely unknown.
Purpose of the Study:
- To review the initiation phase of protein transport across the ER membrane.
- To emphasize the mechanism of signal sequence recognition by the signal recognition particle (SRP).
- To discuss recent findings on polypeptide chain transfer, suggesting a role for a translocation complex.
Main Methods:
- Review of existing literature and recent research findings.
- Analysis of the signal sequence recognition mechanism.
- Examination of the proposed translocation complex and its components.
Main Results:
- The initiation cycle, including signal sequence recognition by the 54 kDa polypeptide of the signal recognition particle (SRP), is well-characterized.
- Recent studies suggest that polypeptide chain transfer occurs via a translocation complex.
- The signal sequence receptor protein (SSR) appears to be a component of this translocation complex.
Conclusions:
- The initiation of protein transport into the ER is understood, particularly signal sequence recognition by SRP.
- The mechanism of polypeptide translocation across the ER membrane is an active area of research.
- Emerging evidence points to a translocation complex, potentially including SSR, as the machinery for protein transfer.
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