Serine/threonine-protein kinase component of the chromosomal passenger complex (CPC), a complex that acts as a key regulator of mitosis. The CPC complex has essential functions at the centromere in ensuring correct chromosome alignment and segregation and is required for chromatin-induced microtubule stabilization and spindle assembly. Involved in the bipolar attachment of spindle microtubules to kinetochores and is a key regulator for the onset of cytokinesis during mitosis. Required for central/midzone spindle assembly and cleavage furrow formation. Key component of the cytokinesis checkpoint, a process required to delay abscission to prevent both premature resolution of intercellular chromosome bridges and accumulation of DNA damage. Phosphorylates 'Ser-10' of histone H3 during mitosis. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Kinase activity is stimulated by both birc5/survivin-binding and cell-cycle specific phosphorylation. Component of the CPC at least composed of survivin/birc5, incenp, cdca8/borealin and/or cdca9/dasra-A, and aurkb/aurora-B. Interacts directly (via N-terminus and kinase domain) with incenp (via C terminus), and may weakly interact (via N-terminus) with birc5.1 to stabilize the complex. Interacts with mtus1. Chromosomal until metaphase but transfers to the midzone microtubule array and the equatorial cortex during anaphase. Phosphorylated, stimulates kinase activity. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. Aurora subfamily. Extended N-terminus.