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Updated: Oct 17, 2026

Identification of MyoD Interactome Using Tandem Affinity Purification Coupled to Mass Spectrometry
14:47

Identification of MyoD Interactome Using Tandem Affinity Purification Coupled to Mass Spectrometry

Published on: May 17, 2016

Stabilization of MyoD by direct binding to p57(Kip2)

E G Reynaud1, M P Leibovitch, L A Tintignac

  • 1Laboratoire de Génétique Oncologique UMR 1599, Centre National de la Recherche Scientifique, Institut Gustave Roussy, 39, rue Camille Desmoulins, 94805 Villejuif, France.

The Journal of Biological Chemistry
|April 15, 2000
PubMed

Insights

p57Kip2 enhances muscle gene activation by stabilizing MyoD, independent of its kinase inhibitory role. This interaction involves specific domains, revealing a novel mechanism for myogenic differentiation.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • MyoD activity and turnover are regulated by phosphorylation.
  • p57Kip2 is known as a cyclin-dependent kinase inhibitor.

Purpose of the Study:

  • To investigate the role of p57Kip2 in MyoD regulation beyond its kinase inhibitory function.
  • To elucidate the mechanism by which p57Kip2 influences MyoD activity and stability.

Main Methods:

  • Transfection of MyoD mutants and p57Kip2.
  • Assays for transactivation of muscle-specific genes.
  • Western blotting to assess protein levels.
  • Co-immunoprecipitation to detect protein interactions.
  • Site-directed mutagenesis and competition assays.

Main Results:

  • p57Kip2 significantly increased the transactivation activity of a non-phosphorylatable MyoD mutant (MyoD Ala200).
  • p57Kip2 overexpression stabilized MyoD Ala200, increasing its half-life.
  • Direct physical interaction between MyoD and p57Kip2 was confirmed via co-immunoprecipitation.
  • The N-terminal domain of p57Kip2 and the basic region of MyoD's bHLH domain mediate this interaction.
  • An alpha-helix domain in p57Kip2, distinct from its Cdk-binding site, is crucial for MyoD interaction.

Conclusions:

  • p57Kip2 positively regulates MyoD activity and stability through a mechanism independent of its Cdk inhibitory function.
  • A direct interaction between p57Kip2 and MyoD, mediated by specific protein domains, is essential for this regulation.
  • This novel interaction highlights a distinct pathway by which p57Kip2 family members promote myogenic differentiation.

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