Haspin inhibitors delay Aurora B activation. (A) Treatment scheme for Aurora B reactivation assays. (B) Immunofluorescence microscopy of CENP-AS7ph and H3S10ph in HeLa cells treated as in A. Bar, 5 µm. (C) Approximately 100 mitotic cells in each condition from one experiment were classified according to the intensity of CENP-AS7ph or H3S10ph staining. Similar results were obtained in a second experiment using the Aurora B inhibitor ZM447439.