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Calcium, Calmodulin, and CaMKII Requirement for Initiation of Centrosome Duplication in Xenopus Egg Extracts
Yutaka Matsumoto,James L. Maller*
Aberrant centrosome duplication is observed in
many tumor cells and may contribute to genomic instability through the
formationof multipolar mitotic spindles. Cyclin-dependent kinase 2 (Cdk2)is required for multiple rounds of centrosome duplication in
Xenopusegg extracts but not for the initial round of
replication. Eggextracts undergo periodic oscillations in the level of
free calcium.We show here that chelation of calcium in egg extracts or
specificinactivation of calcium/calmodulin-dependent protein kinase
II(CaMKII) blocks even initial centrosome duplication, whereas
inactivationof Cdk2 does not. Duplication can be restored to inhibited
extractsby addition of CaMKII and calmodulin. These results indicate
thatcalcium, calmodulin, and CaMKII are required for an essentialstep
in initiation of centrosome duplication. Our data suggestthat calcium
oscillations in the cell cycle may be linked to centrosomeduplication.
Howard Hughes Medical Institute and Department of Pharmacology,
University of Colorado School of Medicine, Denver, CO 80262, USA.
To whom correspondence should be addressed. E-mail:
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In Science Magazine
Yannick Arlot-Bonnemains and Claude Prigent (18 January 2002) Science295 (5554), 455.
[DOI: 10.1126/science.1068917] |Summary »|Full Text »|PDF »