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Updated: May 16, 2026

Assaying Proteasomal Degradation in a Cell-free System in Plants
Published on: March 26, 2014
A U-Box E3 ubiquitin ligase, PUB20, interacts with the Arabidopsis G-protein β subunit, AGB1
Shio Kobayashi1, Daisuke Tsugama, Shenkui Liu
1Asian Natural Environmental Science Center (ANESC), The University of Tokyo, Tokyo, Japan.
Abstract:
An Arabidopsis U-box E3 ubiquitin ligase Plant U-box 20 (PUB20; alternatively called AtCMPG1) was identified as a possible interactor of the Arabidopsis G-protein β subunit, AGB1, by yeast two-hybrid screening. A bimolecular fluorescence complementation (BiFC) assay showed that PUB20 interacted with AGB1 in the nuclei and the cytosol. The expression levels of PUB20 and its closest homolog, PUB21 were stable under many conditions. GUS driven by the PUB20 promoter was active in anthers, pollen, premature seeds and receptacles and GUS driven by the PUB21 promoter was active in anthers and funiculi. PUB20 was found to have autoubiquitination activity in vitro.
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