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Updated: Jun 4, 2025

Profiling Ubiquitin and Ubiquitin-like Dependent Post-translational Modifications and Identification of Significant Alterations
Published on: November 7, 2019
Elucidation of Ubiquitin-Related Functions via an Ubiquitin Overexpression Approach
Ryo Masuda1, Munetaka Yoshikawa1, Ryota Moriuchi2
1Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan.
Abstract:
To identify new ubiquitin-related functions using yeast, we searched for mutants conferring a temperature-sensitivity phenotype that could be rescued through ubiquitin overexpression. Screening of mutants using this overexpression strategy identified SPC2, which encodes a subunit of the endoplasmic reticulum (ER) signal peptidase complex (SPC). Ubiquitin overexpression rescued a high-temperature sensitivity of spc2 deletion mutant, suggesting that ubiquitin could compensate for Spc2 loss-of-function at high temperatures. The double mutant of Spc2 and Hrd1, an ER E3 ubiquitin ligase, showed a synergistic growth defect at higher temperatures. A weak genetic interaction was also observed between spc2Δ and cdc48-3 mutation. The results suggest a close functional relationship between SPC and the ubiquitin-proteasome system in yeast and further provide proof-of-principle for this ubiquitin overexpression approach to identify novel ubiquitin-related genes and associated cellular processes.
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