title: The self-association and activity regulation of LRSAM1 E3 ligase.
abstract: LRSAM1, a RING-type E3 ubiquitin ligase, is essential for regulating cargo sorting, signaling pathways, cell adhesion and anti-bacterial autophagy. It is important to elucidate the mechanism that underlies the regulation of LRSAM1 E3 ligase activity. Here, we reported that LRSAM1 exhibited self-association in vitro and in vivo. We found the self-association of LRSAM1 promotes intermolecular ubiquitination and proved a potential N-terminal ubiquitination. The E3 activity of LRSAM1 is amplified when the RING domain is present in tandem with its N-terminal domain(s). Furthermore, we found that the CC2-SAM domain had a strong inhibitory effect on the E3 activity of LRSAM1 in vitro and blocked ubiquitination of TSG101 in vivo; the tandem CC1 domain, but not the individual CC1 domain, could counteract this inhibition. Collectively, our data characterized the self-association of LRSAM1 and showed how its domains may contribute to its overall activity.
authors.affiliation: The State Key Laboratory Breeding Base of Bioresources and Eco-environments, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Laboratory of Molecular Developmental Biology, School of Life Sciences, Southwest University, Beibei, 400715 Chongqing, China.
authors.forename: Weixiang
authors.initials: W
authors.lastname: Bian
authors.affiliation: The State Key Laboratory Breeding Base of Bioresources and Eco-environments, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Laboratory of Molecular Developmental Biology, School of Life Sciences, Southwest University, Beibei, 400715 Chongqing, China.
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Guo
authors.affiliation: The State Key Laboratory Breeding Base of Bioresources and Eco-environments, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Laboratory of Molecular Developmental Biology, School of Life Sciences, Southwest University, Beibei, 400715 Chongqing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: The State Key Laboratory Breeding Base of Bioresources and Eco-environments, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Laboratory of Molecular Developmental Biology, School of Life Sciences, Southwest University, Beibei, 400715 Chongqing, China. Electronic address: htli@swu.edu.cn.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Li
mesh_terms: D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D000072417:Protein Domains; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: C489657:LRSAM1 protein, human; D044767:Ubiquitin-Protein Ligases
keywords: E3 ligase; Intermolecular ubiquitination; LRSAM1; N-terminal ubiquitination; Self-association