title: Site-specific acetylation of the proteasome activator REGγ directs its heptameric structure and functions.
abstract: The proteasome activator REGγ has been reported to promote degradation of steroid receptor coactivator-3 and cyclin-dependent kinase inhibitors p21, p16, and p19 in a ubiquitin- and ATP-independent manner. A recent comparative analysis of REGγ expression in mouse and human tissues reveals a unique pattern of REGγ in specific cell types, suggesting undisclosed functions and biological importance of this molecule. Despite the emerging progress made in REGγ-related studies, how REGγ function is regulated remains to be explored. In this study, we report for the first time that REGγ can be acetylated mostly on its lysine 195 (Lys-195) residue by CREB binding protein (CBP), which can be reversed by sirtuin 1 (SIRT1) in mammalian cells. Site-directed mutagenesis abrogated acetylation at Lys-195 and significantly attenuated the capability of REGγ to degrade its target substrates, p21 and hepatitis C virus core protein. Mechanistically, acetylation at Lys-195 is important for the interactions between REGγ monomers and ultimately influences REGγ heptamerization. Biological analysis of cells containing REGγ-WT or REGγ-K195R mutant indicates an impact of acetylation on REGγ-mediated regulation of cell proliferation and cell cycle progression. These findings reveal a previously unknown mechanism in the regulation of REGγ assembly and activity, suggesting a potential venue for the intervention of the ubiquitin-independent REGγ proteasome activity.
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China; Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: Jiang
authors.initials: J
authors.lastname: Liu
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China; Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang 310036, China; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
authors.forename: Haibin
authors.initials: H
authors.lastname: Wei
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
authors.forename: Qingxia
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
authors.forename: Weicang
authors.initials: W
authors.lastname: Wang
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Ji
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
authors.forename: Peipei
authors.initials: P
authors.lastname: Shan
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: Sung Yun
authors.initials: SY
authors.lastname: Jung
authors.affiliation: Department of Pathology, the Second Chengdu Municipal Hospital, Chengdu, Sichuan 610017, China.
authors.forename: Pei
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China.
authors.forename: Chuangui
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: Weiwen
authors.initials: W
authors.lastname: Long
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China. Electronic address: bhzhang@bio.ecnu.edu.cn.
authors.forename: Bianhong
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030. Electronic address: xiaotaol@bcm.edu.
authors.forename: Xiaotao
authors.initials: X
authors.lastname: Li
mesh_terms: D000107:Acetylation; D019943:Amino Acid Substitution; D000818:Animals; D001324:Autoantigens / Q000235:genetics / Q000378:metabolism*; D050882:CREB-Binding Protein / Q000235:genetics / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D020125:Mutation, Missense; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization / Q000502:physiology*; D059748:Proteolysis; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism
chemical_list: D001324:Autoantigens; C099558:Ki antigen; D025801:Ubiquitin; D050882:CREB-Binding Protein; C494363:CREBBP protein, human; C494364:Crebbp protein, mouse; D046988:Proteasome Endopeptidase Complex
keywords: Acetylation; Cell Biology; Gene Regulation; Heptamerization; K195; Proteasome; Protein Degradation; Protein Self-assembly; Protein-Protein Interactions; REGγ