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Updated: Jun 24, 2026

In Vitro Analysis of E3 Ubiquitin Ligase Function
Published on: May 14, 2021
TRIM44 interacts with and stabilizes terf, a TRIM ubiquitin E3 ligase
Tomohiko Urano1, Takahiko Usui, Shizu Takeda
1Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Abstract:
Terf/TRIM17 is a member of the TRIM family of proteins, which is characterized by the RING finger, B-box, and coiled-coil domains. In the present study, we found that terf interacts with TRIM44. Terf underwent ubiquitination in vitro in the presence of the E2 enzyme UbcH6; this suggests that terf exhibits E3 ubiquitin ligase activity. It was also found that terf was conjugated with polyubiquitin chains and stabilized by the proteasome inhibitor in mammalian cells; this suggested that terf rendered itself susceptible to proteasomal degradation through polyubiquitination. We also found that TRIM44 inhibited ubiquitination of terf, and thus stabilized the protein. The N-terminal region of TRIM44 contains a zinc-finger domain found in ubiquitin hydrolases (ZF UBP) and ubiquitin specific proteases (USPs). Thus, we proposed that TRIM44 may function as a new class of the "USP-like-TRIM" which regulates the activity of associated TRIM proteins.
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