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Updated: Jul 15, 2026

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
Published on: March 9, 2012
Multiple and stepwise interactions between coatomer and ADP-ribosylation factor-1 (Arf1)-GTP
Zhe Sun1, Frank Anderl, Kathrin Fröhlich
1Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany.
Abstract:
The small GTPase ADP-ribosylation factor-1 (Arf1) plays a key role in the formation of coat protein I (COP I)-coated vesicles. Upon recruitment to the donor Golgi membrane by interaction with dimeric p24 proteins, Arf1's GDP is exchanged for GTP. Arf1-GTP then dissociates from p24, and together with other Golgi membrane proteins, it recruits coatomer, the heptameric coat protein complex of COP I vesicles, from the cytosol. In this process, Arf1 was shown to specifically interact with the coatomer beta and gamma-COP subunits through its switch I region, and with epsilon-COP. Here, we mapped the interaction of the Arf1-GTP switch I region to the trunk domains of beta and gamma-COP. Site-directed photolabeling at position 167 in the C-terminal helix of Arf1 revealed a novel interaction with coatomer via a putative longin domain of delta-COP. Thus, coatomer is linked to the Golgi through multiple interfaces with membrane-bound Arf1-GTP. These interactions are located within the core, adaptor-like domain of coatomer, indicating an organizational similarity between the COP I coat and clathrin adaptor complexes.
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