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Visit our Expo - Redox and Inflammation signaling 2012

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Session XIII : Cell <strong>signaling</strong> pathways leading to regulated chromatin modifications<br />

Poster XIII, 2<br />

Interdependency or Exclusion? Investigation of the phosphorylation state of histone H3<br />

at serine 10 <strong>and</strong> threonine 11 during mitosis<br />

Anne Conradi <strong>and</strong> Karl Heinz Scheidtmann<br />

Institute of Genetics, University of Bonn, Roemerstr. 164, D-53117 Bonn, Germany<br />

E-mail: kh.scheidtmann@uni-bonn.de<br />

Histones are subject to numerous post-translational modifications. During mitosis histone H3<br />

becomes heavily phosphorylated at serine 10 by Aurora-B kinase, as well as at threonine 11<br />

probably by Dlk/ZIP kinase. Phosphorylation at serine 10 occurs along the entire<br />

chormosomal arms, but not at centromeres. It coincides with chromatin condensation <strong>and</strong> may<br />

be involved in initiation of this process. In contrast, phosphorylation at threonine 11 appears<br />

to be centromere-specific <strong>and</strong> may be involved in kinetochore assembly <strong>and</strong>/or function.<br />

These phosphorylation events seem to occur in an exclusive manner which is also supported<br />

by in vitro phosphorylation data. We investigated a possible interrelationship between<br />

Aurora-B <strong>and</strong> Dlk/ZIP kinase. In vitro kinase reactions with purified Aurora-B <strong>and</strong> Dlk/ZIP<br />

kinase revealed no crossphosphorylation between the two kinases. In vivo Aurora-B-specific<br />

kinase inhibitors revealed loss of H3 phosphorylation at serine 10 but not at threonine 11. Our<br />

data suggest that both phosphorylations occur independently.<br />

Acknowledgements:<br />

This work was supported by Deutsche Forschungsgemeinschaft grant Sche 246/16-1.<br />

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