Post-translational modifications of conserved N-terminal tail residues in histones regulate many aspects of chromosome activity. Mitotic phosphorylation of H3 Thr 3 occurs in prophase and dephosphorylation during anaphase. Haspin, a dual serine/threonine kinase, plays an important role in regulation of chromosome and spindle function during mitosis and meiosis via its function in phosphorylation of the threonine residue in the third position of histone 3 (Thr3).
