COPI mediates recycling of an exocytic SNARE by recognition of a ubiquitin sorting signal
- Vanderbilt University, United States
- University of Iowa, United States
Abstract
The COPI coat forms transport vesicles from the Golgi complex and plays a poorly defined role in endocytic trafficking. Here we show that COPI binds K63-linked polyubiquitin and this interaction is crucial for trafficking of a ubiquitinated yeast SNARE (Snc1). Snc1 is a v-SNARE that drives fusion of exocytic vesicles with the plasma membrane, and then recycles through the endocytic pathway to the Golgi for reuse in exocytosis. Removal of ubiquitin from Snc1, or deletion of a β'-COP subunit propeller domain that binds K63-linked polyubiquitin, disrupts Snc1 recycling causing aberrant accumulation in internal compartments. Moreover, replacement of the β'-COP propeller domain with unrelated ubiquitin-binding domains restores Snc1 recycling. These results indicate that ubiquitination, a modification well known to target membrane proteins to the lysosome or vacuole for degradation, can also function as recycling signal to sort a SNARE into COPI vesicles in a non-degradative pathway.
Article and author information
Author details
Funding
National Institutes of Health (5R01GM118452)
- Todd R Graham
Pew Charitable Trusts
- Lauren P Jackson
National Institutes of Health (5R01GM058202)
- Robert C Piper
National Institutes of Health (1R35GM119525)
- Lauren P Jackson
National Institutes of Health (1R01GM118491)
- Jason A MacGurn
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2017, Xu et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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COPI mediates recycling of an exocytic SNARE by recognition of a ubiquitin sorting signal
eLife 6:e28342.
https://doi.org/10.7554/eLife.28342
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