title: Spatial Separation of Plk1 Phosphorylation and Activity.
abstract: Polo-like kinase 1 (Plk1) is one of the major kinases controlling mitosis and cell division. Plk1 is first recruited to the centrosome in S phase, then appears on the kinetochores in late G2, and at the end of mitosis, it translocates to the central spindle. Activation of Plk1 requires phosphorylation of T210 by Aurora A, an event that critically depends on the co-factor Bora. However, conflicting reports exist as to where Plk1 is first activated. Phosphorylation of T210 is first observed at the centrosomes, but kinase activity seems to be restricted to the nucleus in the earlier phases of G2. Here, we demonstrate that Plk1 activity manifests itself first in the nucleus using a nuclear FRET-based biosensor for Plk1 activity. However, we find that Bora is restricted to the cytoplasm and that Plk1 is phosphorylated on T210 at the centrosomes. Our data demonstrate that while Plk1 activation occurs on centrosomes, downstream target phosphorylation by Plk1 first occurs in the nucleus. We discuss several explanations for this surprising separation of activation and function.
authors.affiliation: Department of Cell Biology, The Netherlands Cancer Institute , Amsterdam , Netherlands ; Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands.
authors.forename: Wytse
authors.initials: W
authors.lastname: Bruinsma
authors.affiliation: Department of Cell Biology, The Netherlands Cancer Institute , Amsterdam , Netherlands ; Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands.
authors.forename: Melinda
authors.initials: M
authors.lastname: Aprelia
authors.affiliation: Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands.
authors.forename: Jolanda
authors.initials: J
authors.lastname: Kool
authors.affiliation: Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands ; Laboratory of Cancer Cell Biology, Institute of Molecular Genetics of the ASCR, v. v. i. , Prague , Czech Republic.
authors.forename: Libor
authors.initials: L
authors.lastname: Macurek
authors.affiliation: Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands ; Department of Cell and Molecular Biology, Karolinska Institute , Stockholm , Sweden.
authors.forename: Arne
authors.initials: A
authors.lastname: Lindqvist
authors.affiliation: Department of Cell Biology, The Netherlands Cancer Institute , Amsterdam , Netherlands ; Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht , Utrecht , Netherlands.
authors.forename: René H
authors.initials: RH
authors.lastname: Medema
keywords: aurora kinase; bora; cell cycle; checkpoint recovery; plk1