Polo-like kinase 1 independently controls microtubule-nucleating capacity and size of the centrosome |
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| Authors: | Midori Ohta,Zhiling Zhao,Di Wu,Shaohe Wang,Jennifer L. Harrison,J. Sebastiá n Gó mez-Cavazos,Arshad Desai,Karen F. Oegema |
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| Affiliation: | 1.Ludwig Institute for Cancer Research, La Jolla, CA;2.Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA;3.Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA |
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| Abstract: | Centrosomes are composed of a centriolar core surrounded by a pericentriolar material (PCM) matrix that docks microtubule-nucleating γ-tubulin complexes. During mitotic entry, the PCM matrix increases in size and nucleating capacity in a process called centrosome maturation. Polo-like kinase 1 (PLK1) is recruited to centrosomes and phosphorylates PCM matrix proteins to drive their self-assembly, which leads to PCM expansion. Here, we show that in addition to controlling PCM expansion, PLK1 independently controls the generation of binding sites for γ-tubulin complexes on the PCM matrix. Selectively preventing the generation of PLK1-dependent γ-tubulin docking sites led to spindle defects and impaired chromosome segregation without affecting PCM expansion, highlighting the importance of phospho-regulated centrosomal γ-tubulin docking sites in spindle assembly. Inhibiting both γ-tubulin docking and PCM expansion by mutating substrate target sites recapitulated the effects of loss of centrosomal PLK1 on the ability of centrosomes to catalyze spindle assembly. |
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