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Updated: Jun 10, 2026
06:23
Localization of SUMO-modified Proteins Using Fluorescent Sumo-trapping Proteins
Published on: April 27, 2019
A novel mechanism for SUMO system control: regulated Ulp1 nucleolar sequestration
Yaroslav Sydorskyy1, Tharan Srikumar, Stanley M Jeram
1Ontario Cancer Institute, University of Toronto, MaRS TMDT 9-805, 101 College Street, Toronto, Ontario M5G 1L7, Canada.
Molecular and Cellular Biology
|July 22, 2010
Summary
Environmental stress, like alcohol, alters small ubiquitin-related modifier (SUMO) regulation. The SUMO protease Ulp1 relocates to the nucleolus, increasing SUMO conjugation levels and impacting cellular processes.
Area of Science:
- Cellular biology
- Molecular mechanisms of stress response
- Protein modification
Background:
- Small ubiquitin-related modifiers (SUMOs) regulate protein function and localization.
- SUMO conjugation increases under environmental stress, but regulatory mechanisms are unclear.
- The SUMO protease Ulp1 typically resides at the nuclear pore complex (NPC).
Purpose of the Study:
- To investigate the regulation of the SUMO system under stress conditions.
- To characterize a novel mechanism of SUMO system control involving Ulp1.
- To understand how alcohol exposure affects SUMOylation in Saccharomyces cerevisiae.
Main Methods:
- Investigated the localization of the SUMO protease Ulp1 in yeast cells.
- Used genetic approaches to identify regions of Ulp1 responsible for nucleolar targeting.
- Quantified SUMO conjugate levels under various conditions, including alcohol exposure and Ulp1 sequestration.
Main Results:
- Elevated alcohol levels cause Ulp1 to disengage from the NPC and sequester in the nucleolus.
- Amino acids 150-340 of Ulp1 are necessary and sufficient for its nucleolar targeting.
- Forced Ulp1 sequestration in the nucleolus increases steady-state SUMO conjugate levels, independent of alcohol.
Conclusions:
- A novel mechanism for SUMO system regulation involves stress-induced relocalization of the SUMO protease Ulp1.
- Altering the balance of SUMO conjugation/deconjugation at the NPC impacts cellular SUMOylation.
- This provides new insights into how cells adapt to environmental insults via SUMOylation pathways.
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