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Updated: Feb 2, 2026
In vivo and in vitro Studies of Adaptor-clathrin Interaction
Published on: January 26, 2011
Clathrin adaptor GGA1 modulates myogenesis of C2C12 myoblasts
Mari Isobe1, Sachiko Lee1, Satoshi Waguri2
1Department of Physical and Occupational Therapy, Graduate School of Medicine, Nagoya University, Nagoya, Aichi, Japan.
Abstract:
During myogenesis, myogenic stem cells undergo several sequential events, including cell division, migration, and cell-cell fusion, leading to the formation of multinuclear myotubes, which are the precursors of myofibers. To understand the molecular mechanisms underlying these complex processes, an RNA interference-based gene depletion approach was used. Golgi associated, gamma adaptin ear containing, ARF binding protein 1 (GGA1), a Golgi-resident monomeric clathrin adaptor, was found to be required for the process of myotube formation in C2C12 cells, a cultured murine myoblast cell line. Gga1 mRNA expression was upregulated during myogenesis, and Gga1 depletion prevented the formation of large multi-nucleated myotubes. Moreover, inhibition of lysosomal proteases in Gga1 knockdown myoblasts increased the amount of insulin receptor, suggesting that GGA1 is involved in the cell surface expression and sorting of the insulin receptor. These results suggested that GGA1 plays a significant role in the formation and maturation of myotubes by targeting the insulin receptor to the cell surface to establish functionally mature myofibers.
Insights
Golgi associated, gamma adaptin ear containing, ARF binding protein 1 (GGA1) is crucial for myotube formation. GGA1 regulates insulin receptor cell surface expression, essential for mature muscle fiber development.
Area of Science:
- Muscle biology
- Cellular and molecular biology
- Biochemistry
Background:
- Myogenesis involves stem cell division, migration, and fusion to form multinuclear myotubes, the precursors of myofibers.
- Understanding the molecular regulation of myogenesis is key to muscle development and repair.
Purpose of the Study:
- To investigate the role of Golgi associated, gamma adaptin ear containing, ARF binding protein 1 (GGA1) in myogenesis.
- To elucidate the molecular mechanisms by which GGA1 influences myotube formation and maturation.
Main Methods:
- Utilized an RNA interference-based gene depletion approach in C2C12 murine myoblast cells.
- Analyzed Gga1 mRNA expression during myogenesis.
- Assessed the impact of Gga1 depletion on myotube formation and insulin receptor levels.
Main Results:
- Gga1 mRNA expression was upregulated during myogenesis.
- Depletion of Gga1 inhibited the formation of large, multi-nucleated myotubes.
- Inhibition of lysosomal proteases in Gga1 knockdown cells increased insulin receptor levels, indicating GGA1's role in its sorting and cell surface expression.
Conclusions:
- GGA1 is essential for proper myotube formation and maturation.
- GGA1 facilitates the cell surface targeting of the insulin receptor, which is critical for establishing functional myofibers.
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