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. Stimulates the mitotic kinase activity of aurkb/aurora-B in the CPC. Does not appear to exhibit anti-apoptotic activity (By similarity). {ECO:0000250|UniProtKB:Q8JGN5}.