Nucleophosmin/B23 is a target of CDK2/cyclin E in centrosome duplication.

Okuda, M; Horn, H F; Tarapore, P; Tokuyama, Y; Smulian, A G; Chan, P K; Knudsen, E S; Hofmann, I A et al. · Cell · 2000

basic_science · Level V

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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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