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Updated: Aug 14, 2026

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

Cdc2 kinase directly phosphorylates the cis-Golgi matrix protein GM130 and is required for Golgi fragmentation in

M Lowe1, C Rabouille, N Nakamura

  • 1Cell Biology Laboratory, Imperial Cancer Research Fund, London, United Kingdom.

Cell
|September 30, 1998
PubMed

Insights

Mitotic Golgi fragmentation is driven by Cdc2 kinase phosphorylating GM130 at Ser-25, disrupting p115 binding. This process does not require the MEK1 MAP kinase pathway.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Mitotic Golgi fragmentation is a key event during cell division.
  • Disruption of the interaction between GM130 and p115 is thought to drive Golgi fragmentation.
  • The precise molecular mechanisms and signaling pathways involved remain incompletely understood.

Purpose of the Study:

  • To identify the specific kinase and phosphorylation site responsible for GM130 disruption during mitosis.
  • To investigate the role of the MEK1-MAP kinase pathway in mitotic Golgi fragmentation.

Main Methods:

  • In vitro kinase assays to identify the responsible kinase.
  • Site-directed mutagenesis to pinpoint the key phosphorylation site on GM130.
  • In vitro and in vivo experiments to assess the necessity of MEK1.

Main Results:

  • Serine-25 (Ser-25) of GM130 was identified as the critical phosphorylation site.
  • Cdc2 kinase was identified as the enzyme responsible for GM130 phosphorylation at Ser-25.
  • MEK1 was found not to be required for GM130 phosphorylation or Golgi fragmentation.

Conclusions:

  • Cdc2 directly phosphorylates GM130 at Ser-25, leading to Golgi fragmentation.
  • The MEK1-MAP kinase pathway is not essential for mitotic Golgi fragmentation.
  • This study clarifies the direct kinase involvement in a fundamental cell division process.

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