Mullen JR and Brill SJ (2008) Activation of the Slx5-Slx8 Ubiquitin Ligase by Poly-small Ubiquitin-like Modifier Conjugates. J Biol Chem 283(29):19912-21
Abstract: Protein sumoylation is a regulated process that is important for the health of human and yeast cells. In budding yeast, a subset of sumoylated proteins is targeted for ubiquitination by a conserved heterodimeric Ub ligase, Slx5-Slx8, that is needed to suppress the accumulation of high molecular-weight SUMO conjugates. Structure-function analysis indicates that the Slx5-Slx8 complex contains multiple SUMO-binding domains that are collectively required for in vivo function. To determine the specificity of Slx5-Slx8, we assayed its Ub ligase activity using sumoylated Siz2 as an in vitro substrate. In contrast to un-sumoylated or multi-sumoylated Siz2, substrates containing poly-SUMO conjugates were efficiently ubiquitinated by Slx5-Slx8. Although Siz2 itself was ubiquitinated, the bulk of the Ub was conjugated to SUMO residues. Slx5-Slx8 primarily mono-ubiquitinated the chain's N-terminal SUMO moiety. These data indicate that the Slx5-Slx8 Ub ligase is stimulated by poly-SUMO conjugates and that it can ubiquitinate a poly-SUMO chain.
|Status: Published||Type: Journal Article||PubMed ID: 18499666|
Topics addressed in this paper
Number of different genes curated to this paper: 9
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