Dissecting the M Phase–specific Phosphorylation of Serine–Proline or Threonine–Proline Motifs

Mitotic induction tightly associates with increased reactivity to mitotic phosphoprotein antibody MPM-2. Here we report that phosphorylation of TP motifs surrounded by hydrophobic residues at the −1 and +1 positions plays a dominant role in M phase–associated MPM-2 reactivity. The majority of these motifs are not phosphorylated by mitotic Cdk or MAPK