title: Facilitated Tau Degradation by USP14 Aptamers via Enhanced Proteasome Activity.
abstract: The ubiquitin-proteasome system (UPS) is the primary mechanism by which intracellular proteins, transcription factors, and many proteotoxic proteins with aggregation-prone structures are degraded. The UPS is reportedly downregulated in various neurodegenerative disorders, with increased proteasome activity shown to be beneficial in many related disease models. Proteasomes function under tonic inhibitory conditions, possibly via the ubiquitin chain-trimming function of USP14, a proteasome-associated deubiquitinating enzyme (DUB). We identified three specific RNA aptamers of USP14 (USP14-1, USP14-2, and USP14-3) that inhibited its deubiquitinating activity. The nucleotide sequences of these non-cytotoxic USP14 aptamers contained conserved GGAGG motifs, with G-rich regions upstream, and similar secondary structures. They efficiently elevated proteasomal activity, as determined by the increased degradation of small fluorogenic peptide substrates and physiological polyubiquitinated Sic1 proteins. Additionally, proteasomal degradation of tau proteins was facilitated in the presence of the UPS14 aptamers in vitro. Our results indicate that these novel inhibitory UPS14 aptamers can be used to enhance proteasome activity, and to facilitate the degradation of proteotoxic proteins, thereby protecting cells from various neurodegenerative stressors.
authors.affiliation: Department of Biochemistry and Molecular Biology, Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea.
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Applied Chemistry, College of Applied Sciences, Kyung Hee University, Yongin 446-701, Republic of Korea.
authors.forename: Seung Kyun
authors.initials: SK
authors.lastname: Shin
authors.affiliation: Department of Applied Chemistry, College of Applied Sciences, Kyung Hee University, Yongin 446-701, Republic of Korea.
authors.forename: Yanxialei
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Department of Biochemistry and Molecular Biology, Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea.
authors.forename: Won Hoon
authors.initials: WH
authors.lastname: Choi
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Republic of Korea.
authors.forename: Chaesun
authors.initials: C
authors.lastname: Hong
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Republic of Korea.
authors.forename: Dong-Eun
authors.initials: DE
authors.lastname: Kim
authors.affiliation: Department of Biochemistry and Molecular Biology, Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea.
authors.forename: Min Jae
authors.initials: MJ
authors.lastname: Lee
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D002460:Cell Line; D002478:Cells, Cultured; D006801:Humans; D009690:Nucleic Acid Conformation; D018384:Oxidative Stress; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D011485:Protein Binding; D059748:Proteolysis; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D052156:SELEX Aptamer Technique; D013379:Substrate Specificity; D043222:Ubiquitin Thiolesterase / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity
chemical_list: D052157:Aptamers, Nucleotide; D011994:Recombinant Proteins; C509299:USP14 protein, human; D016875:tau Proteins; D043222:Ubiquitin Thiolesterase; D046988:Proteasome Endopeptidase Complex