title: A kinesin-mediated mechanism that couples centrosomes to nuclei.
abstract: The M-type kinesin isoform, Kif9, has recently been implicated in maintaining a physical connection between the centrosome and nucleus in Dictyostelium discoideum. However, the mechanism by which Kif9 functions to link these two organelles remains obscure. Here we demonstrate that the Kif9 protein is localized to the nuclear envelope and is concentrated in the region underlying the centrosome point of attachment. Nuclear anchorage appears mediated through a specialized transmembrane domain located in the carboxyl terminus. Kif9 interacts with microtubules in in vitro binding assays and effects an endwise depolymerization of the polymer. These results suggest a model whereby Kif9 is anchored to the nucleus and generates a pulling force that reels the centrosome up against the nucleus. This is a novel activity for a kinesin motor, one important for progression of cells into mitosis and to ensure centrosome-nuclear parity in a multinuclear environment.
authors.affiliation: Division of Translational Medicine, Wadsworth Center, NYS Department of Health, Empire State Plaza, PO Box 509, Albany, NY 12201-0509, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Tikhonenko
authors.forename: Valentin
authors.initials: V
authors.lastname: Magidson
authors.forename: Ralph
authors.initials: R
authors.lastname: Gräf
authors.forename: Alexey
authors.initials: A
authors.lastname: Khodjakov
authors.forename: Michael P
authors.initials: MP
authors.lastname: Koonce
mesh_terms: D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D002478:Cells, Cultured; D018385:Centrosome / Q000378:metabolism* / Q000502:physiology; D004023:Dictyostelium / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D016547:Kinesins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis / Q000235:genetics / Q000502:physiology; D008954:Models, Biological; D030781:Organisms, Genetically Modified; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D020033:Protein Isoforms; D015800:Protozoan Proteins; D049452:Green Fluorescent Proteins; D016547:Kinesins