Aurora B Regulates Chromosome Dispersal During Cell Division

Researchers studying the biochemical events that occur during cell division have found that the Aurora B protein regulates correct dispersal of chromosomes into the daughter cells by loading inactive mitotic centromere-associated kinesin (MCAK) onto the chromosomes. Should a chromosome become incorrectly bound to a microtubule from the wrong side of the cell, MCAK is activated and removes the improperly attached microtubule. MCAK is a Kin I kinesin that can depolymerize microtubules.

Investigators at the University of Virginia Medical School (Charlottesville, USA) mapped six Aurora B phosphorylation sites on MCAK in both the centromere-targeting domain and the neck region. They reported in the February 17, 2004, issue of Current Biology that Aurora B activity was required to localize MCAK to centromeres, but not to spindle poles. Aurora B phosphorylation of serine 196 in the neck region of MCAK inhibited its microtubule depolymerization activity.

"Aurora B is a regulatory protein that has been previously implicated in this process,” explained senior author Dr. Todd Stukenberg, assistant professor of biochemistry and molecular genetics at the University of Virginia Medical School. "It is important to study whether mutations in Aurora, MCAK, or the inability to resolve improper microtubule attachments is involved in tumor genesis. It is already clearly established that the Aurora family of kinases is overexpressed in many cancerous solid tumors.”




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