A SUMO-targeted ubiquitin ligase is involved in the degradation of the nuclear pool of the SUMO E3 ligase Siz1.
Mol Biol Cell
; 25(1): 1-16, 2014 Jan.
Article
em En
| MEDLINE
| ID: mdl-24196836
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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
/
Núcleo Celular
/
Proteínas de Saccharomyces cerevisiae
/
Ubiquitina-Proteína Ligases
/
Ubiquitinação
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article