Required for high-fidelity chromosome segregation during the later part of each cell cycle. Has a role in attaching the kinetochores to the microtubules and ensuring that sister kinetochores connect to opposite poles. The promotion of bi-orientation is achieved by selectively detaching kinetochore-microtubule attachments that are not under tension (By similarity). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. Aurora subfamily.