Using a novel in vitro assay which allows us to distinguish vesicle budding from subsequent targeting and fusion steps, we provide the first biological evidence that beta-COP, a component of non-clathrin- coated vesicles believed to mediate intraGolgi transport, is essential for transport of protein from the ER to the cis-Golgi compartment. Incubation in the presence of beta-COP specific antibodies and F(ab) fragments prevents the exit of vesicular stomatitis virus glycoprotein (VSV-G) from the ER. These results demonstrate that beta-COP is required for the assembly of coat complexes mediating vesicle budding. Fractionation of rat liver cytosol revealed that a major biologically active form of beta-COP was found in a high molecular pool (> 1,000 kD) distinct from coatomer and which promoted efficient vesicle budding from the ER. Surprisingly, rab1B could be quantitatively coprecipitated with this beta-COP containing complex and was also essential for function. We suggest that beta-COP functions in an early step during vesicle formation and that rab1B may be recruited as a component of a precoat complex which participates in the export of protein from the ER via vesicular carriers.
Beta-COP is essential for transport of protein from the endoplasmic reticulum to the Golgi in vitro
Frank Peter,H. Plutner,Hengyi Zhu,T. Kreis,W. E. Balch
Published 1993 in Journal of Cell Biology
ABSTRACT
PUBLICATION RECORD
- Publication year
1993
- Venue
Journal of Cell Biology
- Publication date
1993-09-02
- Fields of study
Biology, Medicine
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
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