Related Experiment Videos
Protein translocation by the Sec61/SecY channel
Andrew R Osborne1, Tom A Rapoport, Bert van den Berg
1Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA. Andrew_Osborne@hms.harvard.edu
Annual Review of Cell and Developmental Biology
|October 11, 2005
Summary
The Sec61/SecY channel moves proteins across membranes using three distinct mechanisms. Structural and biochemical studies reveal how ribosomes, BiP, and SecA interact with the channel for protein translocation.
Area of Science:
- Molecular Biology
- Structural Biology
- Cell Biology
Background:
- The Sec61 channel (eukaryotes) and SecY channel (eubacteria, archaea) are essential for protein transport across cellular membranes.
- These channels also integrate proteins with hydrophobic transmembrane segments into lipid bilayers.
- Understanding the mechanisms of protein translocation is crucial for cell biology.
Purpose of the Study:
- To review the translocation mechanisms employed by the Sec61/SecY protein-conducting channel.
- To relate structural and biochemical data to the channel's function.
- To elucidate the roles of binding partners in protein translocation.
Main Methods:
- Review of structural studies of the Sec61/SecY channel.
- Analysis of biochemical and genetic data on protein translocation.
- Integration of structural and functional observations.
Main Results:
- The Sec61/SecY channel utilizes three distinct mechanisms for polypeptide translocation.
- Mechanism 1: Direct feeding of polypeptide by the ribosome.
- Mechanism 2: Ratcheting mechanism mediated by the eukaryotic chaperone BiP.
- Mechanism 3: Pushing mechanism utilized by the bacterial ATPase SecA.
Conclusions:
- The Sec61/SecY channel employs diverse mechanisms involving specific binding partners for protein translocation.
- Structural insights are key to understanding the functional diversity of this essential channel.
- Further research integrating structural, biochemical, and genetic data will refine our understanding of membrane protein biogenesis.