title: Centriole splitting caused by loss of the centrosomal linker protein C-NAP1 reduces centriolar satellite density and impedes centrosome amplification.
abstract: Duplication of the centrosomes is a tightly regulated process. Abnormal centrosome numbers can impair cell division and cause changes in how cells migrate. Duplicated centrosomes are held together by a proteinaceous linker made up of rootletin filaments anchored to the centrioles by C-NAP1. This linker is removed in a NEK2A kinase-dependent manner as mitosis begins. To explore C-NAP1 activities in regulating centrosome activities, we used genome editing to ablate it. C-NAP1-null cells were viable and had an increased frequency of premature centriole separation, accompanied by reduced density of the centriolar satellites, with reexpression of C-NAP1 rescuing both phenotypes. We found that the primary cilium, a signaling structure that arises from the mother centriole docked to the cell membrane, was intact in the absence of C-NAP1, although components of the ciliary rootlet were aberrantly localized away from the base of the cilium. C-NAP1-deficient cells were capable of signaling through the cilium, as determined by gene expression analysis after fluid flow-induced shear stress and the relocalization of components of the Hedgehog pathway. Centrosome amplification induced by DNA damage or by PLK4 or CDK2 overexpression was markedly reduced in the absence of C-NAP1. We conclude that centriole splitting reduces the local density of key centriolar precursors to impede overduplication.
authors.affiliation: Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Flanagan
authors.affiliation: Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, and.|Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Elena
authors.initials: E
authors.lastname: Stavenschi
authors.affiliation: Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
authors.forename: Shivakumar
authors.initials: S
authors.lastname: Basavaraju
authors.affiliation: Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
authors.forename: David
authors.initials: D
authors.lastname: Gaboriau
authors.affiliation: Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, and.|Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland.|Advanced Materials and Bioengineering Research Centre, Trinity College Dublin, and Royal College of Surgeons in Ireland, Dublin 2, Ireland.
authors.forename: David A
authors.initials: DA
authors.lastname: Hoey
authors.affiliation: Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland Ciaran.Morrison@nuigalway.ie.
authors.forename: Ciaran G
authors.initials: CG
authors.lastname: Morrison
mesh_terms: D001324:Autoantigens / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D002460:Cell Line; D002502:Centrioles / Q000378:metabolism* / Q000502:physiology; D018385:Centrosome / Q000378:metabolism; D002923:Cilia / Q000378:metabolism; D006801:Humans; D008938:Mitosis; D015398:Signal Transduction; D008941:Spindle Apparatus / Q000378:metabolism
chemical_list: D001324:Autoantigens; D018797:Cell Cycle Proteins; C111329:CEP250 protein, human