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Quantitative Immunofluorescence Assay to Measure the Variation in Protein Levels at Centrosomes
09:39

Quantitative Immunofluorescence Assay to Measure the Variation in Protein Levels at Centrosomes

Published on: December 20, 2014

A novel centrosome-associated protein with affinity for microtubules

Pascal A Stein1, Christopher P Toret, Adrian N Salic

  • 1Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115-6091, USA.

Journal of Cell Science
|August 3, 2002
PubMed

Insights

Researchers discovered MIR1, a novel mammalian protein that binds to microtubules. MIR1

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Protein Interactions

Background:

  • Opitz G/BBB syndrome is linked to the MID1/midin protein.
  • The function of the novel mammalian protein MIR1 is unknown.
  • MIR1 shares homology with MID1/midin.

Purpose of the Study:

  • To investigate the function and properties of the novel mammalian protein MIR1.
  • To determine MIR1's role in microtubule dynamics and cell division.

Main Methods:

  • Tissue culture cells were used to study MIR1 localization and behavior.
  • Overexpression of MIR1 was performed to assess its effects.
  • Immunofluorescence microscopy was employed to visualize protein localization.

Main Results:

  • MIR1 binds to microtubules and localizes to the centrosome.
  • MIR1 dissociates from centrosomes during mitosis (G2/M transition) and returns during anaphase.
  • Overexpressed MIR1 stabilizes and bundles microtubules in interphase, detaching them from the centrosome.
  • MIR1 affects gamma-tubulin localization at spindle poles during mitosis.
  • Microtubule binding is dependent on MIR1 oligomerization and weakened by cdk phosphorylation.

Conclusions:

  • MIR1 is a novel microtubule-binding protein with a dynamic centrosome localization during the cell cycle.
  • MIR1 plays a role in regulating microtubule organization and stability.
  • Phosphorylation by cdk sites may regulate MIR1's interaction with microtubules during mitosis.

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