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Updated: Jan 17, 2026

In Vitro Analysis of E3 Ubiquitin Ligase Function
Published on: May 14, 2021
Polyubiquitin architecture editing on collided ribosomes maintains persistent RQC activity
Shota Tomomatsu1,2, Yoshitaka Matsuo3, Fumiaki Ohtake4
1Division of RNA and Gene Regulation, Institute of Medical Science, The University of Tokyo, Minato-Ku, 108-8639, Japan.
Two deubiquitinating enzymes (DUBs), Ubp2 and Ubp3, edit ubiquitin chains on yeast uS10, promoting ribosome-associated quality control (RQC) and ensuring persistent RQC activity.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Ribosome-associated quality control (RQC) manages stalled ribosomes.
- K63-linked polyubiquitination of ribosomal protein uS10 is vital for RQC-trigger (RQT) complex recruitment.
- Mechanisms of polyubiquitin maintenance and recycling on colliding ribosomes are not fully understood.
Purpose of the Study:
- To elucidate the roles of deubiquitinating enzymes (DUBs) in ubiquitin chain editing and recycling during RQC.
- To investigate how Ubp2 and Ubp3 influence polyubiquitin architecture on uS10.
- To understand the impact of specific ubiquitin linkages on RQT-mediated ribosome dissociation.
Main Methods:
- Yeast genetics and biochemistry.
- Analysis of polyubiquitin chain composition on uS10.
- Investigation of DUB activity in vitro and in vivo.
Main Results:
- Ubp2 removes K63-linked polyubiquitin chains from uS10 on free 40S subunits for recycling.
- Ubp3 cleaves K48-linked and mixed-linkage polyubiquitin chains from uS10 on translating ribosomes.
- K48-linked ubiquitin chains on uS10 inhibit RQT-mediated ribosome dissociation.
Conclusions:
- Ubp2 and Ubp3 are key DUBs that edit and recycle polyubiquitin chains on uS10.
- These DUB activities are essential for maintaining sustained RQC function.
- The ubiquitin code on uS10 regulates RQC progression and ribosome quality control.
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