Protein modification by the small ubiquitin-like modifier (SUMO) plays important roles in genome maintenance. In Saccharomyces cerevisiae, proper regulation of sumoylation is known to be essential for viability in certain DNA repair mutants. Here we find the opposite result; proper regulation of sumoylation is lethal in certain DNA repair mutants. Yeast cells lacking the repair factors TDP1 and WSS1 are synthetically lethal due to their redundant roles in removing Top1-DNA covalent complexes (Top1ccs). A screen for suppressors of tdp1∆ wss1∆ synthetic lethality isolated mutations in genes known to control global sumoylation levels including ULP1, ULP2, SIZ2 and SLX5 The results suggest that alternative pathways of repair become available when sumoylation levels are altered. Curiously, both suppressor mutations that were isolated in the Slx5 subunit of the SUMO-targeted Ub ligase created new lysine residues. These "slx5-K" mutations localize to a 398 amino acid (aa) domain that is completely free of lysine, and they result in the auto-ubiquitination and partial proteolysis of Slx5. The decrease in Slx5-K protein leads to the accumulation of high molecular weight SUMO conjugates, and the residual Ub ligase activity is needed to suppress inviability presumably by targeting polysumoylated Top1ccs. This "lysine desert" is found in the subset of large fungal Slx5 proteins, but not its smaller orthologs such as RNF4. The lysine desert solves a problem that Ub ligases encounter when evolving novel functional domains.
Pharmacology, Toxicology and Pharmaceutical Science
1
4%
Other
2
7%
Unknown
4
14%
Attention Score in Context
Attention Score in Context
This research output has an Altmetric Attention Score of 4. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 03 July 2026.
All research outputs
#10,068,467
of 33,082,196 outputs
Outputs from Genetics
#3,725
of 8,830 outputs
Outputs of similar age
#117,723
of 349,465 outputs
Outputs of similar age from Genetics
#74
of 137 outputs
Altmetric has tracked 33,082,196 research outputs across all sources so far. This one has received more attention than most of these and is in the 68th percentile.
So far Altmetric has tracked 8,830 research outputs from this source. They typically receive more attention than average, with a mean Attention Score of 8.3. This one has gotten more attention than average, scoring higher than 56% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 349,465 tracked outputs that were published within six weeks on either side of this one in any source. This one has gotten more attention than average, scoring higher than 65% of its contemporaries.
We're also able to compare this research output to 137 others from the same source and published within six weeks on either side of this one. This one is in the 44th percentile – i.e., 44% of its contemporaries scored the same or lower than it.
