Abstract
The NIMA-family kinases Nek9/Nercc1, Nek6 and Nek7 form a signalling module required for mitotic spindle assembly. Nek9, the upstream kinase, is activated during prophase at centrosomes although the details of this have remained elusive. We now identify Plk1 as Nek9 direct activator and propose a two-step activation mechanism that involves Nek9 sequential phosphorylation by CDK1 and Plk1. Furthermore, we show that Plk1 controls prophase centrosome separation through the activation of Nek9 and ultimately the phosphorylation of the mitotic kinesin Eg5 at Ser1033, a Nek6/7 site that together with the CDK1 site Thr926 we establish contributes to the accumulation of Eg5 at centrosomes and is necessary for subsequent centrosome separation and timely mitosis. Our results provide a basis to understand signalling downstream of Plk1 and shed light on the role of Eg5, Plk1 and the NIMA-family kinases in the control of centrosome separation and normal mitotic progression.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Cell Cycle / drug effects
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Cell Cycle / genetics
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Cell Cycle Proteins / antagonists & inhibitors
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Cell Cycle Proteins / physiology*
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Cells, Cultured
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Centrosome / drug effects
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Centrosome / metabolism*
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Centrosome / physiology
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Enzyme Activation / drug effects
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Enzyme Activation / genetics
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Enzyme Activation / physiology
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Gene Knockdown Techniques
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HeLa Cells
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Humans
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Kinesins / antagonists & inhibitors
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Kinesins / genetics
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Kinesins / metabolism
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Kinesins / physiology*
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Mitosis / drug effects
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Mitosis / genetics
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Mitosis / physiology
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NIMA-Related Kinases
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Phosphorylation / drug effects
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Phosphorylation / genetics
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Phosphorylation / physiology
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Polo-Like Kinase 1
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Protein Serine-Threonine Kinases / antagonists & inhibitors
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Protein Serine-Threonine Kinases / physiology*
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Proto-Oncogene Proteins / antagonists & inhibitors
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins / physiology*
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RNA, Small Interfering / pharmacology
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Signal Transduction / drug effects
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Signal Transduction / genetics
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Signal Transduction / physiology
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Transfection
Substances
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Cell Cycle Proteins
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KIF11 protein, human
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Proto-Oncogene Proteins
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RNA, Small Interfering
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NEK6 protein, human
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NEK7 protein, human
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NEK9 protein, human
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NIMA-Related Kinases
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Protein Serine-Threonine Kinases
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Kinesins