Inhibition of centrosome separation after DNA damage: a role for Nek2.
DNA damage results in cell cycle arrest in G2. Centrosomes also separate in G2, raising the question of whether separation occurs during the DNA damage-induced G2 arrest. Nek2, the mammalian homologue of NIMA, is a cell cycle-regulated serine/threonine protein kinase that regulates centrosome separation during G2. Here we show that damaged cells fail to activate Nek2. Both Nek2 levels and activity are reduced after DNA damage. Radiation inhibits the premature centrosome splitting induced by overexpression of Nek2, indicating that Nek2 is involved in activation of the G2 checkpoint and is not secondary to cell cycle arrest. We confirm using siRNA that centrosome separation and cell growth are impaired in the absence of Nek2. These studies define a previously unreported DNA damage response of inhibition of centrosome separation mechanistically linked to Nek2.
Fletcher
Lynda
L
Department of Pathology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
Cerniglia
George J
GJ
Nigg
Erich A
EA
Yend
Tim J
TJ
Muschel
Ruth J
RJ
D001483:Base Sequence; D015153:Blotting, Western; D018385:Centrosome / Q000528:radiation effects; D004249:DNA Damage; D017931:DNA Primers; D005455:Fluorescent Antibody Technique; D016195:G2 Phase / Q000528:radiation effects; D006801:Humans; D000072379:NIMA-Related Kinases; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D014407:Tumor Cells, Cultured
D017931:DNA Primers; C089441:NEK2 protein, human; D000072379:NIMA-Related Kinases; D017346:Protein Serine-Threonine Kinases