title: MST1 limits the kinase activity of aurora B to promote stable kinetochore-microtubule attachment.
abstract: The establishment and maintenance of proper attachment of kinetochores to microtubules are required to prevent chromosome missegregation and consequent chromosomal instability and tumorigenesis. Although MST1 (mammalian sterile 20-like kinase 1) has been implicated in many aspects of cell cycle regulation and tumor suppression [1], its precise mechanism of action has remained largely unknown. We now show that MST1 promotes accurate kinetochore-microtubule attachment by modulating the kinase activity of Aurora B. HeLa cells depleted of MST1 failed to develop stable end-on kinetochore-microtubule attachment, giving rise to unaligned mitotic chromosomes. The misaligned chromosomes activated the Mad2- and BubR1-dependent spindle checkpoint response, resulting in a delay in anaphase onset. The kinase activity of Aurora B, which promotes destabilization of kinetochore-microtubule attachment [2-4], was increased in cells depleted of MST1 or NDR1, a downstream kinase of MST1. MST1 and NDR1 associated with Aurora B. Moreover, MST1 directly phosphorylated Aurora B and inhibited its kinase activity in vitro. Depletion of Aurora B restored the stability of kinetochore-microtubule attachment in cells depleted of MST1 or NDR1. MST1 is thus a key regulator of Aurora B activity that ensures mitotic chromosome congression and accurate chromosome segregation.
authors.affiliation: Department of Biological Sciences, Biomedical Research Center, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Oh
authors.forename: Mi Ju
authors.initials: MJ
authors.lastname: Kim
authors.forename: Su Jung
authors.initials: SJ
authors.lastname: Song
authors.forename: Tackhoon
authors.initials: T
authors.lastname: Kim
authors.forename: Dongjun
authors.initials: D
authors.lastname: Lee
authors.forename: Seung-Hae
authors.initials: SH
authors.lastname: Kwon
authors.forename: Eui-Ju
authors.initials: EJ
authors.lastname: Choi
authors.forename: Dae-Sik
authors.initials: DS
authors.lastname: Lim
mesh_terms: D064107:Aurora Kinase B; D064127:Aurora Kinases; D002453:Cell Cycle / Q000502:physiology; D005786:Gene Expression Regulation; D006367:HeLa Cells; D017228:Hepatocyte Growth Factor / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D018386:Kinetochores / Q000502:physiology*; D008870:Microtubules / Q000502:physiology*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D011518:Proto-Oncogene Proteins; C082332:macrophage stimulating protein; D017228:Hepatocyte Growth Factor; C576921:AURKB protein, human; D064107:Aurora Kinase B; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; C491614:STK38 protein, human