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Temporal changes in Hec1 phosphorylation control kinetochore–microtubule attachment stability during mitosis
Keith F. DeLuca, Susanne M. A. Lens, Jennifer G. DeLuca


Precise control of the attachment strength between kinetochores and spindle microtubules is essential to preserve genomic stability. Aurora B kinase has been implicated in regulating the stability of kinetochore–microtubule attachments but its relevant kinetochore targets in cells remain unclear. Here, we identify multiple serine residues within the N-terminus of the kinetochore protein Hec1 that are phosphorylated in an Aurora-B-kinase-dependent manner during mitosis. On all identified target sites, Hec1 phosphorylation at kinetochores is high in early mitosis and decreases significantly as chromosomes bi-orient. Furthermore, once dephosphorylated, Hec1 is not highly rephosphorylated in response to loss of kinetochore–microtubule attachment or tension. We find that a subpopulation of Aurora B kinase remains localized at the outer kinetochore even upon Hec1 dephosphorylation, suggesting that Hec1 phosphorylation by Aurora B might not be regulated wholly by spatial positioning of the kinase. Our results define a role for Hec1 phosphorylation in kinetochore–microtubule destabilization and error correction in early mitosis and for Hec1 dephosphorylation in maintaining stable attachments in late mitosis.

  • Accepted October 21, 2010.
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