Coordinate regulation of the mother centriole component nlp by nek2 and plk1 protein kinases.
Mitotic entry requires a major reorganization of the microtubule cytoskeleton. Nlp, a centrosomal protein that binds gamma-tubulin, is a G(2)/M target of the Plk1 protein kinase. Here, we show that human Nlp and its Xenopus homologue, X-Nlp, are also phosphorylated by the cell cycle-regulated Nek2 kinase. X-Nlp is a 213-kDa mother centriole-specific protein, implicating it in microtubule anchoring. Although constant in abundance throughout the cell cycle, it is displaced from centrosomes upon mitotic entry. Overexpression of active Nek2 or Plk1 causes premature displacement of Nlp from interphase centrosomes. Active Nek2 is also capable of phosphorylating and displacing a mutant form of Nlp that lacks Plk1 phosphorylation sites. Importantly, kinase-inactive Nek2 interferes with Plk1-induced displacement of Nlp from interphase centrosomes and displacement of endogenous Nlp from mitotic spindle poles, while active Nek2 stimulates Plk1 phosphorylation of Nlp in vitro. Unlike Plk1, Nek2 does not prevent association of Nlp with gamma-tubulin. Together, these results provide the first example of a protein involved in microtubule organization that is coordinately regulated at the G(2)/M transition by two centrosomal kinases. We also propose that phosphorylation by Nek2 may prime Nlp for phosphorylation by Plk1.
Rapley
Joseph
J
Department of Biochemistry, University of Leicester, University Rd., Leicester LE1 7RH, United Kingdom.
Baxter
Joanne E
JE
Blot
Joelle
J
Wattam
Samantha L
SL
Casenghi
Martina
M
Meraldi
Patrick
P
Nigg
Erich A
EA
Fry
Andrew M
AM
D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002502:Centrioles / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D008969:Molecular Sequence Data; D000072379:NIMA-Related Kinases; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D014404:Tubulin / Q000378:metabolism; D014407:Tumor Cells, Cultured; D029867:Xenopus Proteins / Q000378:metabolism*; D014982:Xenopus laevis; D000097869:Polo-Like Kinase 1
D018797:Cell Cycle Proteins; D000072379:NIMA-Related Kinases; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D014404:Tubulin; D029867:Xenopus Proteins; D000097869:Polo-Like Kinase 1; C089441:NEK2 protein, human