title: RNF20 promotes the polyubiquitination and proteasome-dependent degradation of AP-2α protein.
abstract: Transcription factor activator protein 2α (AP-2α) is a negative regulator of adipogenesis by repressing the transcription of CCAAT/enhancer binding protein (C/EBPα) gene. During adipogenesis, AP-2α is degraded, leading to transcriptional up-regulation of C/EBPα. However, the mechanism for AP-2α degradation is not clear. Here, using immunoprecipitation assay and mass spectrometry, we identified ring finger protein 20 (RNF20) as an AP-2α-interacting protein in 3T3-L1 preadipocytes. RNF20 has been proved to be an E3 ubiquitin ligase for both histone H2B and tumor suppressor ErbB3-binding protein 1 (Ebp1). In this study, we demonstrated that RNF20 co-localized and interacted with AP-2α, and promoted its polyubiquitination and proteasome-dependent degradation. Over-expression of RNF20 inhibited the activity of AP-2α and rescued the C/EBPα expression which was inhibited by AP-2α. These results suggested that RNF20 may play roles in adipocyte differentiation by stimulating ubiquitin-proteasome-dependent degradation of AP-2α.
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Science, Hunan Normal University, Changsha 410081, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Ren
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Sheng
authors.forename: Yijun
authors.initials: Y
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Yi
authors.forename: Qiuzhi
authors.initials: Q
authors.lastname: Zhou
authors.forename: Jianlin
authors.initials: J
authors.lastname: Zhou
authors.forename: Shuanglin
authors.initials: S
authors.lastname: Xiang
authors.forename: Xiang
authors.initials: X
authors.lastname: Hu
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism; D050156:Adipogenesis / Q000235:genetics; D000818:Animals; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000096:biosynthesis; D002454:Cell Differentiation; D051379:Mice; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D050656:Transcription Factor AP-2 / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D050656:Transcription Factor AP-2; C571257:RNF20 protein, mouse; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex
keywords: AP-2α; C/EBPα; E3 ubiquitin ligase; RNF20; ubiquitin–proteasome-dependent degradation