Sorting of a multi-subunit ubiquitin ligase complex in the endolysosome system
Abstract
The yeast Dsc E3 ligase complex has long been recognized as a Golgi-specific protein ubquitination system. It shares a striking sequence similarity to the Hrd1 complex that plays critical roles in the ER-associated degradation pathway. Using biochemical purification and mass spectrometry, we identified two novel Dsc subunits, which we named as Gld1 and Vld1. Surprisingly, Gld1 and Vld1 do not coexist in the same complex. Instead, they compete with each other to form two functionally independent Dsc subcomplexes. The Vld1 subcomplex takes the AP3 pathway to reach the vacuole membrane, whereas the Gld1 subcomplex travels through the VPS pathway and is cycled between Golgi and endosomes by the retromer. Thus, instead of being Golgi-specific, the Dsc complex can regulate protein levels at three distinct organelles, namely Golgi, endosome, and vacuole. Our study provides a novel model of achieving multi-tasking for transmembrane ubiquitin ligases with interchangeable trafficking adaptors.
Article and author information
Author details
Funding
University of Michigan (Startup fund)
- Ming Li
University of Michigan (MCubed fund)
- Ming Li
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Christopher G Burd, Yale School of Medicine, United States
Version history
- Received: October 27, 2017
- Accepted: January 19, 2018
- Accepted Manuscript published: January 22, 2018 (version 1)
- Version of Record published: February 13, 2018 (version 2)
Copyright
© 2018, Yang 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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