title: Regulation of microtubule-based microtubule nucleation by mammalian polo-like kinase 1.
abstract: Bipolar spindle formation is pivotal for accurate segregation of mitotic chromosomes during cell division. A growing body of evidence suggests that, in addition to centrosome- and chromatin-based microtubule (MT) nucleation, MT-based MT nucleation plays an important role for proper bipolar spindle formation in various eukaryotic organisms. Although a recently discovered Augmin complex appears to play a central role in this event, how Augmin is regulated remains unknown. Here we provide evidence that a mammalian polo-like kinase 1 (Plk1) localizes to mitotic spindles and promotes MT-based MT nucleation by directly regulating Augmin. Mechanistically, we demonstrated that Cdc2-dependent phosphorylation on a γ-tubulin ring complex (γ-TuRC) recruitment protein, Nedd1/GCP-WD, at the previously uncharacterized S460 residue induces the Nedd1-Plk1 interaction. This step appeared to be critical to allow Plk1 to phosphorylate the Hice1 subunit of the Augmin complex to promote the Augmin-MT interaction and MT-based MT nucleation from within the spindle. Loss of either the Nedd1 S460 function or the Plk1-dependent Hice1 phosphorylation impaired both the Augmin-MT interaction and γ-tubulin recruitment to the spindles, thus resulting in improper bipolar spindle formation that ultimately leads to mitotic arrest and apoptotic cell death. Thus, via the formation of the Nedd1-Plk1 complex and subsequent Augmin phosphorylation, Plk1 regulates spindle MT-based MT nucleation to accomplish normal bipolar spindle formation and mitotic progression.
authors.affiliation: Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Johmura
authors.forename: Nak-Kyun
authors.initials: NK
authors.lastname: Soung
authors.forename: Jung-Eun
authors.initials: JE
authors.lastname: Park
authors.forename: Li-Rong
authors.initials: LR
authors.lastname: Yu
authors.forename: Ming
authors.initials: M
authors.lastname: Zhou
authors.forename: Jeong K
authors.initials: JK
authors.lastname: Bang
authors.forename: Bo-Yeon
authors.initials: BY
authors.lastname: Kim
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Veenstra
authors.forename: Raymond L
authors.initials: RL
authors.lastname: Erikson
authors.forename: Kyung S
authors.initials: KS
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D016203:CDC2 Protein Kinase; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D019926:Cyclin B / Q000378:metabolism; D018844:Cyclin-Dependent Kinases; D017931:DNA Primers / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D022101:Microtubule-Organizing Center / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism; D000097869:Polo-Like Kinase 1
chemical_list: D016203:CDC2 Protein Kinase; D018797:Cell Cycle Proteins; D019926:Cyclin B; D018844:Cyclin-Dependent Kinases; D017931:DNA Primers; D008869:Microtubule-Associated Proteins; D046912:Multiprotein Complexes; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D014404:Tubulin; D000097869:Polo-Like Kinase 1; C000628759:HAUS8 protein, human; C509189:NEDD1 protein, human; C528899:CDK1 protein, human