Phosphorylates in vitro histone H3 at 'Ser-10' and 'Ser- 28'; but not at 'Thr-3' or 'Thr-11'. Colocalizes with phosphorylated histone H3 during mitosis. Associates with cytoskeletal structures that are necessary for cytokinesis and with the microtubule spindle. {ECO:0000269|PubMed:16028112; ECO:0000269|PubMed:17087760}.