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Studying Proteolysis of Cyclin B at the Single Cell Level in Whole Cell Populations
10:54

Studying Proteolysis of Cyclin B at the Single Cell Level in Whole Cell Populations

Published on: September 17, 2012

Cybip, a starfish cyclin B-binding protein, is involved in meiotic M-phase exit

Nicolas Offner1, Jean Derancourt, Jean Claude Lozano

  • 1UMR 7628, Laboratoire Arago, BP 44, F-66651 Banyuls sur Mer Cedex, France.

Biochemical and Biophysical Research Communications
|December 14, 2002
PubMed

Insights

Researchers identified Cybip, a starfish oocyte protein that binds cyclin B independently of cdc2. This protein

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Protein Interactions

Background:

  • Cyclin B is crucial for cell cycle regulation.
  • Identifying cyclin B-binding proteins is key to understanding cell cycle control.
  • Starfish oocytes are a model system for studying oocyte maturation.

Purpose of the Study:

  • To identify starfish oocyte proteins that bind monomeric cyclin B.
  • To characterize the interaction between cyclin B and the identified protein.
  • To investigate the role of this protein in oocyte maturation.

Main Methods:

  • Affinity chromatography using a low-affinity cyclin B variant.
  • Recombinant protein expression and binding assays.
  • Microinjection of protein and antibodies into starfish oocytes.
  • Assay of H1 kinase and MPF activity.
  • Monitoring of first polar body emission.

Main Results:

  • A 15kDa protein, Cybip, was identified as a cyclin B-binding protein.
  • Cybip binds cyclin B independently of cdc2.
  • Microinjection of Cybip or anti-Cybip antibodies inhibited H1 kinase and MPF inactivation.
  • First polar body emission was also inhibited.

Conclusions:

  • Cybip is a true cyclin B-binding protein.
  • Cybip plays a significant role in regulating starfish oocyte maturation.
  • Cybip's function is linked to MPF inactivation and polar body emission.

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