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Updated: Jul 13, 2026

Analysis of Cell Cycle Position in Mammalian Cells
Published on: January 21, 2012
Nucleophosmin/B23 is a target of CDK2/cyclin E in centrosome duplication
M Okuda1, H F Horn, P Tarapore
1Department of Cell Biology, Neurobiology, and Anatomy, University of Cincinnati College of Medicine, Ohio 45267, USA.
Abstract:
In animal cells, duplication of centrosomes and DNA is coordinated. Since CDK2/cyclin E triggers initiation of both events, activation of CDK2/cyclin E is thought to link these two events. We identified nucleophosmin (NPM/B23) as a substrate of CDK2/cyclin E in centrosome duplication. NPM/B23 associates specifically with unduplicated centrosomes, and NPM/B23 dissociates from centrosomes by CDK2/cyclin E-mediated phosphorylation. An anti-NPM/B23 antibody, which blocks this phosphorylation, suppresses the initiation of centrosome duplication in vivo. Moreover, expression of a nonphosphorylatable mutant NPM/ B23 in cells effectively blocks centrosome duplication. Thus, NPM/B23 is a target of CDK2/cyclin E in the initiation of centrosome duplication.
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