Abstract
M phase induction in eukaryotic cell cycles is associated with a burst of protein phosphorylation, primarily at serine or threonine followed by proline (S/TP motif). The mitotic phosphoprotein antibody MPM-2 recognizes a significant subset of mitotically phosphorylated S/TP motifs; however, the required surrounding sequences of and the key kinases that phosphorylate these S/TP motifs remain to be determined. By mapping the mitotic MPM-2 epitopes in Xenopus Cdc25C and characterizing the mitotic MPM-2 epitope kinases in Xenopus oocytes and egg extracts, we have determined that phosphorylation of TP motifs that are surrounded by hydrophobic residues at both -1 and +1 positions plays a dominant role in M phase-associated burst of MPM-2 reactivity. Although mitotic Cdk and MAPK may phosphorylate subsets of these motifs that have a basic residue at the -2 position and a proline residue at the -2 position, respectively, the majority of these motifs that are preferentially phosphorylated in mitosis do not have these features. TheMphase-associated burst of MPM-2 reactivity can be induced in Xenopus oocytes and egg extracts in the absence of MAPK or Cdc2 activity. These findings indicate that the M phase-associated burst of MPM-2 reactivity represents a novel type of protein phosphorylation in mitotic regulation.
Original language | English (US) |
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Pages (from-to) | 1470-1481 |
Number of pages | 12 |
Journal | Molecular Biology of the Cell |
Volume | 21 |
Issue number | 9 |
DOIs | |
State | Published - May 1 2010 |
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology
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