Document Type
Article
Department/Program
Biology
Pub Date
1-2014
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.
Abstract
The Slx5/Slx8 heterodimer constitutes a SUMO-targeted ubiquitin ligase (STUbL) with an important role in SUMO-targeted degradation and SUMO-dependent signaling. This STUbL relies on SUMO-interacting motifs in Slx5 to aid in substrate targeting and carboxy-terminal RING domains in both Slx5 and Slx8 for substrate ubiquitylation. In budding yeast cells, Slx5 resides in the nucleus, forms distinct foci, and can associate with double-stranded DNA breaks. However, it remains unclear how STUbLs interact with other proteins and their substrates. To examine the targeting and functions of the Slx5/Slx8 STUbL, we constructed and analyzed truncations of the Slx5 protein. Our structure–function analysis reveals a domain of Slx5 involved in nuclear localization and in the interaction with Slx5, SUMO, Slx8, and a novel interactor, the SUMO E3 ligase Siz1. We further analyzed the functional interaction of Slx5 and Siz1 in vitro and in vivo. We found that a recombinant Siz1 fragment is an in vitro ubiquitylation target of the Slx5/Slx8 STUbL. Furthermore, slx5∆ cells accumulate phosphorylated and sumoylated adducts of Siz1 in vivo. Specifically, we show that Siz1 can be ubiquitylated in vivo and is degraded in an Slx5-dependent manner when its nuclear egress is prevented in mitosis. In conclusion, our data provide a first look into the STUbL-mediated regulation of a SUMO E3 ligase.
Recommended Citation
Westerbeck, Jason W.; Pasupala, Nagesh; Guillotte, Mark; Szymanski, Eva; Matson, Brooke C.; Esteban, Cecilia; and Kerscher, Oliver, A SUMO-targeted ubiquitin ligase is involved in the degradation of the nuclear pool of the SUMO E3 ligase Siz1 (2014).
https://doi.org/10.1091/mbc.E13-05-0291
DOI
https://doi.org/10.1091/mbc.E13-05-0291
Publisher Statement
Copyright: The American Society for Cell Biology
