Aurora B is the catalytic subunit of the chromosomal passenger complex (CPC), 
which coordinates mitotic processes through phosphorylation of key regulatory 
proteins. In prometaphase, the CPC is enriched at the centromeres to regulate 
the spindle checkpoint and kinetochore-microtubule interactions. Centromeric CPC 
binds to histone H3 that is phosphorylated at T3 (H3T3ph) by Aurora B-stimulated 
Haspin. PP1/Repo-Man acts antagonistically to Haspin and dephosphorylates H3T3ph 
at the chromosome arms but is somehow prevented from causing a net 
dephosphorylation of centromeric H3T3ph during prometaphase. Here, we show that 
Aurora B phosphorylates Repo-Man at S893, preventing its recruitment by 
histones. We also identify PP2A as a mitotic interactor of Repo-Man that 
dephosphorylates S893 and thereby promotes the targeting of Repo-Man to 
chromosomes and the dephosphorylation of H3T3ph by PP1. Thus, 
Repo-Man-associated PP1 and PP2A collaborate to oppose the chromosomal targeting 
of Aurora B. We propose that the reciprocal feedback regulation of Haspin and 
Repo-Man by Aurora B generates a robust bistable response that culminates in the 
centromeric targeting of the CPC during prometaphase.