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Updated: Jun 17, 2026
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Identification of MyoD Interactome Using Tandem Affinity Purification Coupled to Mass Spectrometry
Published on: May 17, 2016
Nuclear function of Smad7 promotes myogenesis.
Tetsuaki Miyake1, Nezeka S Alli, John C McDermott
1Department of Biology, York University, St., Toronto, Ontario M3J 1P3, Canada.
Molecular and Cellular Biology
|December 10, 2009
Summary
Smad7 promotes muscle cell differentiation independently of TGF-beta signaling. This nuclear Smad7 function interacts with MyoD, enhancing muscle gene activation and overcoming inhibitory signals.
Area of Science:
- Molecular Biology
- Cell Signaling
- Muscle Development
Background:
- The canonical role of Smad7 in transforming growth factor beta (TGF-beta) signaling is inhibitory.
- Smad7's previously reported promyogenic role in myogenic cells suggested functions beyond TGF-beta receptor inhibition.
Purpose of the Study:
- To investigate the nuclear function of Smad7 in myogenesis, independent of its interaction with the TGF-beta receptor.
- To elucidate the mechanism by which Smad7 promotes myogenic differentiation.
Main Methods:
- Engineering of a Smad7-nuclear localization signal (NLS) chimera to ensure nuclear localization and bypass receptor binding.
- Assays to assess Smad3 activation, myogenic gene activation, and phenotypic myogenesis.
- Reporter and myogenic conversion assays to study Smad7's interaction with MyoD and MEK.
Main Results:
- Smad7-NLS enhanced myogenic gene activation and phenotypic myogenesis without repressing Smad3 activation.
- Smad7 physically interacts with MyoD and counteracts the inhibitory effects of active MEK on MyoD.
- The balance between Smad7 and active MEK critically regulates MyoD transcriptional activity.
Conclusions:
- Smad7 possesses a nuclear, TGF-beta-independent coactivator function essential for promoting myogenesis.
- Smad7's interaction with MyoD and modulation of MEK signaling are key mechanisms underlying its promyogenic activity.
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