title: BUB3 that dissociates from BUB1 activates caspase-independent mitotic death (CIMD).
abstract: The cell death mechanism that prevents aneuploidy caused by a failure of the spindle checkpoint has recently emerged as an important regulatory paradigm. We previously identified a new type of mitotic cell death, termed caspase-independent mitotic death (CIMD), which is induced during early mitosis by partial BUB1 (a spindle checkpoint protein) depletion and defects in kinetochore-microtubule attachment. In this study, we have shown that survived cells that escape CIMD have abnormal nuclei, and we have determined the molecular mechanism by which BUB1 depletion activates CIMD. The BUB3 protein (a BUB1 interactor and a spindle checkpoint protein) interacts with p73 (a homolog of p53), specifically in cells wherein CIMD occurs. The BUB3 protein that is freed from BUB1 associates with p73 on which Y99 is phosphorylated by c-Abl tyrosine kinase, resulting in the activation of CIMD. These results strongly support the hypothesis that CIMD is the cell death mechanism protecting cells from aneuploidy by inducing the death of cells prone to substantial chromosome missegregation.
authors.affiliation: Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Niikura
authors.forename: H
authors.initials: H
authors.lastname: Ogi
authors.forename: K
authors.initials: K
authors.lastname: Kikuchi
authors.forename: K
authors.initials: K
authors.lastname: Kitagawa
mesh_terms: D000818:Animals; D020169:Caspases / Q000235:genetics / Q000502:physiology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D016923:Cell Death / Q000502:physiology*; D002467:Cell Nucleus / Q000648:ultrastructure; D002470:Cell Survival; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008938:Mitosis; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D000075223:Poly-ADP-Ribose Binding Proteins; D020033:Protein Isoforms / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D016315:Proto-Oncogene Proteins c-abl / Q000378:metabolism; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C489444:BUB3 protein, human; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D020033:Protein Isoforms; C000606460:TP73 protein, human; C000606368:Trp73 protein, mouse; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; D016315:Proto-Oncogene Proteins c-abl; C584277:BUB1 protein, human; C584281:Bub1 protein, mouse; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases; D020169:Caspases