Aurora Activation

Science's STKE  22 Apr 2003:
Vol. 2003, Issue 179, pp. tw158-TW158
DOI: 10.1126/stke.2003.179.tw158

During vertebrate cell mitosis, a bipolar spindle is assembled to facilitate chromosome segregation. Aurora A kinase localizes to the spindle through interaction with a motor binding protein TPX2 (targeting protein for Xenopus kinesin-like protein). However, little is known about what activates Aurora A. Protein kinase A is known to phosphorylate and activate Aurora A in vitro. Eyers et al. now report that in addition to being an Aurora A substrate, in vitro TPX2 stimulates the autophosphorylation and activation of the kinase. Mutational analysis identified the amino terminus of TPX2 as sufficient to bind and activate Aurora A. This mechanism of activation is unusual, as many protein kinases are activated by direct phosphorylation by upstream kinase. The dual function of TPX2 in localization and activation of Aurora A may serve as a stringent control for proper spindle formation and ordered mitosis.

P. A. Eyers, E. Erikson, L. G. Chen, J. L. Maller, A novel mechanism for activation of the protein kinase Aurora A. Curr. Biol. 13, 691-697 (2003). [Online Journal]