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The Emp24 complex recruits a specific cargo molecule into endoplasmic reticulum-derived vesicles
The Journal of Cell Biology
|March 8, 2000
Summary
The Emp24 complex in yeast is crucial for transporting proteins from the endoplasmic reticulum (ER) to the Golgi. This study reveals Emp24p acts as a cargo receptor, directly facilitating the packaging of Gas1p protein into ER-derived vesicles.
Area of Science:
- Cell biology
- Protein transport
- Molecular mechanisms
Background:
- The p24 family of proteins, including Emp24p and Erv25p, form complexes involved in protein transport.
- Their precise roles and locations in the endoplasmic reticulum (ER) to Golgi pathway remain unclear.
Purpose of the Study:
- To investigate the specific function of the Emp24 complex in protein trafficking.
- To determine if Emp24p directly mediates cargo selection during vesicle formation from the ER.
Main Methods:
- Utilized yeast as a model organism.
- Employed cross-linking experiments to assess protein interactions.
- Analyzed the effect of emp24 mutations on protein packaging into ER-derived vesicles.
Main Results:
- Emp24p is essential for the efficient packaging of the lumenal cargo protein Gas1p into ER-derived vesicles.
- Direct cross-linking confirmed interactions between Emp24p, Erv25p, and Gas1p within these vesicles.
- The unrelated protein Gap1p was unaffected, indicating cargo specificity.
Conclusions:
- The Emp24 complex functions as a cargo receptor during vesicle biogenesis at the ER.
- This mechanism is critical for the selective export of proteins like Gas1p to the Golgi apparatus.