title: Deacetylation of the mitotic checkpoint protein BubR1 at lysine 250 by SIRT2 and subsequent effects on BubR1 degradation during the prometaphase/anaphase transition.
abstract: Mitotic catastrophe, a form of cell death that occurs during mitosis and after mitotic slippage to a tetraploid state, plays an important role in the efficacy of cancer cell killing by microtubule inhibitors. Prolonged mitotic arrest at the spindle assembly checkpoint (SAC) is a well-known requirement for mitotic catastrophe and, thus, for conferring sensitivity to microtubule inhibitors. We previously reported that downregulation of SIRT2, a member of the sirtuin family of NAD+-dependent deacetylases, confers resistance to microtubule inhibitors by abnormally prolonging mitotic arrest and thus compromising the cell death pathway after mitotic slippage. Thus, turning off SAC activation after a defined period is an additional requirement for efficient post-slippage death. Here, we investigated whether SIRT2 deacetylates BubR1, which is a core component of the SAC; acetylation of BubR1 at lysine 250 (K250) during prometaphase inhibits its APC/C-dependent proteolysis and thus regulates timing in anaphase entry. We showed that SIRT2 deacetylates BubR1 K250 both in vitro and in vivo. We also found that SIRT2 knockdown leads to increased levels of BubR1 acetylation at prometaphase; however, this increase is not substantial to elevate the levels of total BubR1 or delay the transition from prometaphase to anaphase. The present study shows that SIRT2 is a deacetylase for BubR1 K250, although the abnormally prolonged SAC activation observed in SIRT2 knockdown cells is not accompanied by a change in BubR1 levels or by delayed progression from prometaphase to anaphase.
authors.affiliation: Division of Human Genome Science, Department of Molecular and Cellular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Suematsu
authors.affiliation: Division of Human Genome Science, Department of Molecular and Cellular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan.
authors.forename: Yanze
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Immunology, Osaka City University Graduate School of Medicine, Asahi-machi 1-4-3, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Hirotada
authors.initials: H
authors.lastname: Kojima
authors.affiliation: Department of Immunology, Osaka City University Graduate School of Medicine, Asahi-machi 1-4-3, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Nakajima
authors.affiliation: Chromosome Engineering Research Center, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Oshimura
authors.affiliation: Division of Human Genome Science, Department of Molecular and Cellular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan; Chromosome Engineering Research Center, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan. Electronic address: toshiaki.inoue.nishida@gmail.com.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Inoue
mesh_terms: D000107:Acetylation; D000705:Anaphase; D002460:Cell Line; D055785:Gene Knockdown Techniques; D006801:Humans; D049468:Prometaphase; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism*; D059748:Proteolysis; D056565:Sirtuin 2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: C584277:BUB1 protein, human; D017346:Protein Serine-Threonine Kinases; C474199:SIRT2 protein, human; D056565:Sirtuin 2
keywords: Acetylation/deacetylation; BubR1; Microtubule inhibitors; SIRT2; Spindle assembly checkpoint