Characterization of TRIM62 as a RING finger E3 ubiquitin ligase and its subcellular localization.

TRIM62, also named DEAR1, is a member of the TRIM/RBCC family, which includes proteins with conserved RING finger, B-box and coiled-coil domains. Several reports have identified a role for this family in cancer, retroviral infection and innate immunity. In this study, the E3 ubiquitin ligase activity and subcellular localization of TRIM62 were characterized. TRIM62, in association with the E2 enzyme UbcH5b, was found to catalyze self-ubiquitination in vitro, a process that required an intact RING finger domain. A ubiquitination assay performed in HEK293T cells further confirmed the E3 ubiquitin ligase activity and self-ubiquitination activity of TRIM62 and the requirement of the RING finger domain. Importantly, the treatment of HEK293T cells with a proteasome inhibitor stabilized poly-ubiquitinated TRIM62, indicating that self-ubiquitination promoted the proteasomal degradation of TRIM62. Additionally, TRIM62 and its two mutants were distinctly localized in the cytoplasm in both HEK293T and HeLa cells. Collectively, our data indicate that TRIM62, a cytoplasmic protein, is a RING finger domain-dependent E3 ubiquitin ligase that catalyzes self-ubiquitination both in vitro and in vivo.

Huang F ，Xiao H ，Sun BL ，Yang RG ... -  《-》

Identification of TRIM22 as a RING finger E3 ubiquitin ligase.

Duan Z ，Gao B ，Xu W ，Xiong S ... -  《-》

Characterisation of human RING finger protein TRIM69, a novel testis E3 ubiquitin ligase and its subcellular localisation.

The E3 ubiquitin ligase activity and subcellular localisation of human TRIM69 (hTRIM69) gene were studied. It was found that hTRIM69 mediated ubiquitination in an E2 conjugating enzyme selective fashion in vitro and an intact RING finger domain was indispensible for the process. Further evidences showed that hTRIM69 could mediate ubiquitination in vivo, which could be enhanced by a proteasome inhibitor. hTRIM69 was found to localise in both the cytoplasm and the nucleus in a speckled aggregating pattern, which also required an intact RING finger domain. Collectively, hTRIM69 is a novel E3 ubiquitin ligase identified from human testis and may function to ubiquitinate its particular substrates during spermatogenesis.

Han Y ，Li R ，Gao J ，Miao S ，Wang L ... -  《-》

TRIM proteins as RING finger E3 ubiquitin ligases.

Ikeda K ，Inoue S 《Advances in Experimental Medicine and Biology》

Ubiquitination of E3 ubiquitin ligase TRIM5 alpha and its potential role.

Yamauchi K ，Wada K ，Tanji K ，Tanaka M ，Kamitani T ... -  《FEBS Journal》