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 (By similarity). Does not appear to exhibit anti-apoptotic activity. Plays a role in increasing blood vessel size during development. {ECO:0000250|UniProtKB:Q804H7; ECO:0000269|PubMed:15853809; ECO:0000269|PubMed:16759290}.