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Updated: Jul 3, 2026

Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta
Published on: December 5, 2019
Identification of TRIM22 as a RING finger E3 ubiquitin ligase
1Institute for Immunobiology, Department of Immunology, Shanghai Medical College of Fudan University, 138 Yi Xue Yuan Road, Shanghai 200032, PR China.
Abstract:
TRIM22, a member of the TRIM family proteins which contain RING finger, B-box, and coiled-coil domains, has been reported as a transcriptional regulator and involved in various cellular processes. In this study, the E3 ubiquitin ligase activity, a novel property of TRIM22, was demonstrated. It was found that TRIM22 underwent self-ubiquitylation in vitro in combination with the E2 enzyme UbcH5B and the ubiquitylation was dependent on its RING finger domain. Further evidences showed that TRIM22 could also be self-ubiquitylated in vivo. Importantly, TRIM22 was conjugated with poly-ubiquitin chains and stabilized by the proteasome inhibitor in 293T cells, suggesting that TRIM22 targeted itself for proteasomal degradation through the poly-ubiquitylation. We also found that TRIM22 was located in the nucleus, indicating that TRIM22 might function as a nuclear E3 ubiquitin ligase.
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