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Updated: Jul 31, 2025

Global Identification of Co-Translational Interaction Networks by Selective Ribosome Profiling
Published on: October 7, 2021
Sec16 and Sed4 interdependently function as interaction and localization partners at ER exit sites.
Tomohiro Yorimitsu1, Ken Sato1
1Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan.
Sed4, a Sec12 homolog, concentrates at ER exit sites (ERES) and recruits Sec16, a key COPII organizer. Their interaction ensures proper localization, revealing interdependent functions in yeast protein transport.
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Trafficking
Background:
- COPII proteins are essential for transport carrier formation at ER exit sites (ERES).
- Sec12 initiates COPII assembly, while Sec16's localization mechanism at ERES is unclear.
- Sec16 is crucial for COPII organization but its recruitment to ERES is independent of Sec12.
Purpose of the Study:
- To elucidate the mechanism of Sec16 localization to ERES.
- To investigate the role of Sec12 homologs in Sec16 recruitment.
- To understand the interdependent functions of Sec16 and Sed4 at ERES.
Main Methods:
- Yeast genetics and protein localization studies in Saccharomyces cerevisiae.
- Analysis of protein-protein interactions between Sec16 and Sed4.
- Investigating the role of Sed4's luminal domain and O-mannosylation.
Main Results:
- Sed4, a Sec12 homolog, concentrates at ERES and mediates Sec16 localization.
- The Sec16-Sed4 interaction is critical for their correct ERES localization.
- Sed4's luminal domain directs its ERES localization and is involved in its self-interaction, influenced by O-mannosylation.
Conclusions:
- Sed4 plays a key role in recruiting Sec16 to ERES, independent of Sec12.
- The interaction between Sec16 and Sed4 is essential for their proper localization and function.
- Sed4's luminal domain and O-mannosylation are critical for its ERES concentration and self-association, highlighting interdependent localization mechanisms.
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