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Updated: Sep 3, 2025
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In Vitro Ubiquitination and Deubiquitination Assays of Nucleosomal Histones
Published on: July 25, 2019
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Ubiquitination drives COPI priming and Golgi SNARE localization
Swapneeta S Date1, Peng Xu1, Nathaniel L Hepowit2
1Department of Biological Sciences, Vanderbilt University, Nashville, United States.
Elife
|July 29, 2022
Summary
Coat protein I (COPI) recognizes ubiquitin, which is essential for Golgi SNARE localization and stabilizes interactions with Arf and SNAREs in yeast. This finding reveals a new model for how ubiquitination drives COPI priming events in protein trafficking.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Understanding SNARE localization in the Golgi complex is key to deciphering protein trafficking in the secretory pathway.
- SNAREs are implicated in priming coat protein I (COPI) assembly for vesicle incorporation, but regulatory mechanisms remain unclear.
Purpose of the Study:
- To investigate the role of ubiquitin recognition by COPI in SNARE trafficking and the stabilization of Arf-COPI-SNARE interactions in Saccharomyces cerevisiae.
- To elucidate the mechanisms by which posttranslational modifications influence COPI priming events essential for Golgi SNARE localization.
Main Methods:
- Utilized Saccharomyces cerevisiae as a model organism.
- Investigated the binding capabilities of COPI, specifically its N-terminal WD repeat domain of β'-COP and an unrelated ubiquitin-binding domain, for ubiquitin and dilysine motifs.
- Analyzed the ubiquitination status of COPI, ArfGAP Glo3, and Golgi SNAREs (Bet1, Gos1).
- Assessed the impact of ubiquitination on the binding affinities between Arf, COPI, and Gos1.
Main Results:
- COPI's ability to bind ubiquitin, independent of the dilysine motif, is critical for the correct localization of Golgi SNAREs Bet1 and Gos1.
- COPI, ArfGAP Glo3, and several Golgi SNAREs were found to be ubiquitinated.
- Ubiquitination significantly enhances the binding of Arf and COPI to the SNARE Gos1.
- Contrary to proposals, Glo3 was not enriched in the ubiquitin-stabilized SNARE-Arf-COPI complex but rather in COPI complexes lacking SNAREs.
Conclusions:
- Ubiquitin recognition by COPI is essential for proper Golgi SNARE localization and for stabilizing interactions within the Arf-COPI-SNARE machinery.
- Posttranslational modification, specifically ubiquitination, plays a crucial role in priming COPI-mediated events necessary for Golgi SNARE trafficking.
- A novel model is proposed where ubiquitination drives COPI priming events, impacting Golgi SNARE localization and protein trafficking.
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