title: Arkadia enhances BMP signalling through ubiquitylation and degradation of Smad6.
abstract: Arkadia, a positive regulator of Smad-dependent signalling via the transforming growth factor-β (TGF-β) family, is an E3 ubiquitin ligase that induces ubiquitylation and proteasome-dependent degradation of TGF-β suppressors such as Smad7, c-Ski and SnoN. In this study, we examined the effects of Arkadia on bone morphogenetic protein (BMP)-induced osteoblast differentiation. Knockdown of Arkadia reduced mineralization and expression of osteoblast differentiation markers. Furthermore, we showed that Smad6, a BMP-specific inhibitory Smad, is a target of Arkadia: wild-type (WT) Arkadia, but not the C937A (CA) mutant lacking E3 ubiquitin-ligase activity, induced ubiquitylation and proteasome-dependent degradation of Smad6. Accordingly, protein levels of Smad6, Smad7 and c-Ski were elevated in MEFs from Arkadia KO mice. Finally, expression of Arkadia attenuated blockade of BMP signalling by Smad6 in a transcriptional reporter assay. These results demonstrate that Smad6 is a novel target of Arkadia, and that Arkadia positively regulates BMP signalling via degradation of Smad6, Smad7 and c-Ski/SnoN.
authors.affiliation: Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Tsubakihara
authors.affiliation: Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Hikita
authors.affiliation: Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
authors.forename: Sachi
authors.initials: S
authors.lastname: Matsushita
authors.affiliation: Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
authors.forename: Natsuki
authors.initials: N
authors.lastname: Matsushita
authors.affiliation: Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-im
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Oshima
authors.affiliation: Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Miyazawa
authors.affiliation: Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-im
authors.forename: Takeshi
authors.initials: T
authors.lastname: Imamura
mesh_terms: D000818:Animals; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D051379:Mice; D018345:Mice, Knockout; D015398:Signal Transduction; D051905:Smad6 Protein / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000172:deficiency / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D051905:Smad6 Protein; C497803:Smad6 protein, mouse; C427283:Rnf111 protein, mouse; D044767:Ubiquitin-Protein Ligases
keywords: Arkadia; BMP; Smad6; proteasome-dependent degradation; ubiquitylation