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. Probably acts through association with AURKB or AURKC. Seems to bind directly to microtubules. Controls the kinetochore localization of BUB1.