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MG53-induced IRS-1 ubiquitination negatively regulates skeletal myogenesis and insulin signalling

Jae-Sung Yi1, Jun Sub Park, Young-Mi Ham

  • 1Department of Life Sciences, Korea University, Seoul 136-701, Korea.

Nature Communications
|August 23, 2013
PubMed

Insights

Mitsugumin 53 (MG53) is an E3 ligase that targets insulin receptor substrate 1 (IRS-1) for ubiquitination, inhibiting muscle growth. Inhibiting MG53

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Metabolic Disease Research

Background:

  • Mitsugumin 53 (MG53) is known to negatively regulate skeletal myogenesis.
  • Insulin receptor substrate 1 (IRS-1) is a key signaling molecule in insulin pathways.
  • The precise mechanism by which MG53 affects skeletal myogenesis and insulin signaling remains incompletely understood.

Purpose of the Study:

  • To elucidate the molecular mechanism of MG53's regulation of skeletal myogenesis.
  • To investigate the role of MG53 in IRS-1 ubiquitination and insulin signaling.
  • To explore the therapeutic potential of targeting the MG53-IRS-1 interaction for metabolic disorders.

Main Methods:

  • Investigated MG53's enzymatic activity as an ubiquitin E3 ligase.
  • Utilized molecular manipulations to disrupt MG53's E3-ligase function.
  • Examined IRS-1 ubiquitination levels and skeletal myogenesis in vitro and in MG53 knockout mice.
  • Assessed insulin signaling and insulin resistance in response to a high-fat/high-sucrose diet.

Main Results:

  • MG53 functions as an ubiquitin E3 ligase, promoting IRS-1 ubiquitination via UBE2H.
  • Disrupting MG53's E3-ligase activity enhances skeletal myogenesis and elevates IRS-1 levels.
  • MG53 knockout mice exhibit improved insulin signaling and resistance to diet-induced metabolic disorders.
  • Human diabetic patients and insulin-resistant mice show normal MG53 expression levels.

Conclusions:

  • MG53 negatively regulates skeletal myogenesis by ubiquitinating and targeting IRS-1 for degradation.
  • Enhanced IRS-1 levels and signaling in MG53-deficient muscle protect against insulin resistance.
  • Altered MG53 expression is not a primary cause of metabolic disorders.
  • Targeting the MG53-IRS-1 interaction presents a potential therapeutic strategy for insulin resistance-associated metabolic diseases.

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