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Centrosome‐targeting region of CG‐NAP causes centrosome amplification by recruiting cyclin E‐cdk2 complex
Author(s) -
Nishimura Tamako,
Takahashi Mikiko,
Kim HonSong,
Mukai Hideyuki,
Ono Yoshitaka
Publication year - 2005
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/j.1365-2443.2005.00816.x
Subject(s) - centrosome , centrosome cycle , biology , microbiology and biotechnology , nap , cyclin dependent kinase , cyclin a , cyclin e , cyclin dependent kinase 2 , cell cycle , genetics , kinase , protein kinase a , cell , neuroscience
Centrosome duplication occurs once per cell cycle and is thought to be triggered by cyclin E‐cdk2. However, it is largely unknown how the duplication is regulated. Here, we found that the expression of the centrosome‐targeting region of CG‐NAP ( c entrosome and G olgi‐localized PK N ‐associated p rotein), which we designate as CG‐NAP/D, increased the number of centrosomes in Chinese hamster ovary (CHO)‐K1 cells. The amplified centrosomes co‐localized with centrosome markers γ‐tubulin, centrin‐2 and kendrin as well as endogenous CG‐NAP. When CG‐NAP/D was dislocated from centrosomes by deleting the centrosome‐targeting domain or by fusing with a membrane‐targeting sequence, centrosome amplification was suppressed. CG‐NAP/D interacted with exogenously expressed cyclin E, which co‐localized at centrosomes. The immunoprecipitates of CG‐NAP/D exhibited histone H1 kinase activity, suggesting the co‐immunoprecipitation of active cyclin‐cdk complexes. Furthermore, centrosome fractions prepared from cells expressing CG‐NAP/D contained increased amount of cdk2 compared with those from control cells. Centrosome amplification by CG‐NAP/D was suppressed by co‐expression of a mutant cyclin E unable to interact with cdk2. These results suggest that CG‐NAP/D causes centrosome amplification by anchoring excess amount of cyclin E‐cdk2 to centrosomes and, possibly, CG‐NAP participates in centrosome duplication by recruiting cyclin E‐cdk2 to centrosomes in normal cell cycle.