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Proline-rich domain in dynamin-2 has a low microtubule-binding activity: how is this activity controlled during

Makiko Morita1, Kozue Hamao, Shunsuke Izumi

  • 1Department of Biological Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.

Journal of Biochemistry
|October 5, 2010
PubMed

Insights

Mitotic HeLa cells utilize cyclin B-Cdc2 kinase to phosphorylate dynamin-2

Area of Science:

  • Cell biology
  • Molecular biology
  • Biochemistry

Background:

  • Dynamin, a large GTPase, accumulates in dividing cells, with its proline-rich domain (PRD) implicated in microtubule binding.
  • The precise role of PRD in controlling dynamin-microtubule interactions during mitosis remains unclear.

Purpose of the Study:

  • To investigate the regulation of dynamin-2's microtubule-binding activity by its PRD during mitosis.
  • To identify specific kinases that modify the PRD in mitotic HeLa cells.

Main Methods:

  • Biochemical assays to assess microtubule-binding activity of dynamin-2's PRD.
  • Identification of mitotic kinase activities targeting the PRD in HeLa cell extracts.
  • Site-directed mutagenesis to pinpoint phosphorylation sites on the PRD.

Main Results:

  • The microtubule-binding activity of dynamin-2's PRD was found to be low.
  • Cyclin B-Cdc2 kinase was identified as a key mitotic kinase that phosphorylates the PRD.
  • Phosphorylation of the PRD at Ser(764) and/or Thr(766) by cyclin B-Cdc2 kinase significantly reduced its microtubule-binding activity.

Conclusions:

  • Phosphorylation of the dynamin-2 PRD by cyclin B-Cdc2 kinase is a critical regulatory mechanism.
  • This phosphorylation event modulates dynamin-2's interaction with microtubules during mitosis in HeLa cells.

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