Structure of the Sec23p/24p and Sec13p/31p complexes of COPII
G Z Lederkremer1, Y Cheng, B M Petre
1Department of Cell Biology, Center for Blood Research, Harvard Medical School, Boston, MA 02115-5701, USA.
Summary
Researchers investigated the structure of protein complexes involved in COPII vesicle transport. They revealed the molecular organization of Sec23p/24p and Sec13p/31p complexes, crucial for endoplasmic reticulum to Golgi transport.
Area of Science:
- Cell Biology
- Molecular Biology
- Structural Biology
Background:
- COPII-coated vesicles mediate essential protein transport from the endoplasmic reticulum (ER) to the Golgi complex.
- This process is reconstituted by three cytosolic components: Sar1p GTPase, Sec23p/24p complex, and Sec13p/31p complex.
Purpose of the Study:
- To elucidate the molecular organization and three-dimensional structure of the Sec23p/24p and Sec13p/31p complexes.
- To contribute to understanding the overall architecture of the COPII coat.
Main Methods:
- Biochemistry
- Electron microscopy
- Three-dimensional reconstruction
Main Results:
- The Sec23p/24p complex exhibits a bone-shaped structure (17 nm) with two globular domains (Sec23p and Sec24p).
- The Sec13p/31p complex is an elongated heterotetramer (28-30 nm) with five linked globular domains.
- Detailed subunit interactions and coat appearance were analyzed.
Conclusions:
- A model for COPII coat organization is proposed based on the determined structures and subunit interactions.
- This research provides structural insights into a fundamental cellular transport mechanism.
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