Spatial Compartmentalization Specializes the Function of Aurora A and Aurora B

Aurora kinase A and B share great similarity in sequences, structures, and phosphorylation motif, yet they show different localizations and play distinct crucial roles. The factors that determine such differences are largely unknown. Here we targeted Aurora A to the localization of Aurora B and found that Aurora A phosphorylates the substrate of Aurora B and substitutes its function in spindle checkpoint. In return, the centrosome targeting of Aurora B substitutes the function of Aurora A in the mitotic entry. Expressing the chimera proteins of the Auroras with exchanged N termini in cells indicates that the divergent N termini are also important for their spatiotemporal localizations and functions. Collectively, we demonstrate that functional divergence of Aurora kinases is determined by spatial compartmentalization, and their divergent N termini also contribute to their spatial and functional differentiation. Background: Aurora kinases show different localizations and play distinct roles, yet the mechanisms remain largely unknown. Results: Different localization leads to functional divergence of the Auroras and their N termini also contribute to the localization. Conclusion: Both N/C termini of Aurora A/B contribute to their spatial compartmentalization and function. Significance: Functional divergence of Aurora kinases is largely determined by their localizations through binding with partners/substrates.