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Published on: January 24, 2017
Several ADP-ribosylation factor (Arf) isoforms support COPI vesicle formation
Vincent Popoff1, Julian D Langer2, Ingeborg Reckmann1
1Heidelberg University Biochemistry Center (BZH), University of Heidelberg, INF 364, 69120 Heidelberg, Germany.
The Journal of Biological Chemistry
|August 17, 2011
Summary
ADP-ribosylation factors (Arfs) are crucial for vesicle formation. This study reveals Arf1, Arf4, Arf5, and Arf3
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Trafficking
Background:
- Newly synthesized proteins and lipids travel via vesicular carriers through the secretory pathway.
- ADP-ribosylation factors (Arfs) are conserved GTPases regulating molecular coat recruitment for vesicle biogenesis.
- Arf1 and coatomer are known to mediate COPI vesicle formation from Golgi membranes.
Purpose of the Study:
- To investigate the roles of different ADP-ribosylation factor (Arf) isoforms in COPI vesicle formation.
- To analyze the association of Arf isoforms with COPI vesicles.
- To understand potential functional competition among Arf members in vesicle biogenesis.
Main Methods:
- In vitro generation of COPI vesicles from Golgi membranes and purified cytosol.
- Association analysis of Arf isoforms with purified COPI vesicles.
- Functional assays using recombinant myristoylated Arf proteins to assess vesicle formation.
Main Results:
- Arf1, Arf4, and Arf5 were found to associate with in vitro-generated COPI vesicles.
- Arf1, Arf4, and Arf5 individually supported COPI vesicle formation.
- Arf3 also mediated vesicle biogenesis but was excluded from vesicles when other Arf isoforms were present, indicating functional competition.
Conclusions:
- Multiple Arf isoforms, including Arf1, Arf4, Arf5, and unexpectedly Arf3, can mediate COPI vesicle formation.
- Functional competition exists between different Arf isoforms during COPI vesicle biogenesis.
- This study elucidates the complex regulatory mechanisms of Arf family members in vesicular transport.
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