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Updated: May 10, 2026

Live Cell Imaging of Chromosome Segregation During Mitosis
06:39

Live Cell Imaging of Chromosome Segregation During Mitosis

Published on: March 14, 2018

Intermediate filament reorganization during mitosis is mediated by p34cdc2 phosphorylation of vimentin

Y H Chou1, J R Bischoff, D Beach

  • 1Department of Cell, Molecular and Structural Biology, Northwestern University, Chicago, Illinois 60611.

Cell
|September 21, 1990
PubMed

Insights

During mitosis, intermediate filament (IF) proteins like vimentin are hyperphosphorylated by a p34cdc2 kinase complex, leading to IF network disassembly. This phosphorylation is crucial for cellular reorganization during M phase.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Intermediate filaments (IFs) depolymerize during mitosis.
  • Vimentin and desmin are hyperphosphorylated at specific sites during mitosis.
  • The kinases responsible for vimentin hyperphosphorylation are not fully characterized.

Purpose of the Study:

  • To characterize a vimentin kinase involved in mitotic IF reorganization.
  • To identify the components of the vimentin kinase complex.
  • To determine if vimentin is a substrate of p34cdc2.

Main Methods:

  • Purification of vimentin kinase activity from mitotic BHK-21 cell lysates.
  • Copurification with histone H1 kinase activity and p13suc1-Sepharose binding.
  • In vitro phosphorylation assays using purified kinase complex and vimentin.

Main Results:

  • Vimentin kinase activity copurified with histone H1 kinase and bound to p13suc1-Sepharose.
  • The purified kinase complex contained p34cdc2, 65 kDa, and 110 kDa polypeptides.
  • The kinase complex phosphorylated vimentin in vitro at mitotic sites and induced disassembly of IFs.

Conclusions:

  • Vimentin is a direct substrate of the p34cdc2 kinase complex.
  • Phosphorylation of vimentin by p34cdc2 contributes to the reorganization of the intermediate filament network during M phase.
  • This study identifies a key mechanism for mitotic cellular restructuring.

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