PC4/Tis7/IFRD1 stimulates skeletal muscle regeneration and is involved in myoblast differentiation as a regulator of MyoD and NF-κB

Laura Micheli, Luca Leonardi, Filippo Conti, Giovanna Maresca, Sandra Colazingari, Elisabetta Mattei, Sergio A. Lira, Stefano Farioli-Vecchioli, Maurizia Caruso, Felice Tirone

Research output: Contribution to journalArticlepeer-review


In skeletal muscle cells, the PC4 (Tis7/Ifrd1) protein is known to function as a coactivator of MyoD by promoting the transcriptional activity of myocyte enhancer factor 2C (MEF2C). In this study, we show that up-regulation of PC4 in vivo in adult muscle significantly potentiates injury-induced regeneration by enhancing myogenesis. Conversely, we observe that PC4 silencing in myoblasts causes delayed exit from the cell cycle, accompanied by delayed differentiation, and we show that such an effect is MyoD-dependent. We provide evidence revealing a novel mechanism underlying the promyogenic actions of PC4, by which PC4 functions as a negative regulator of NF-κB, known to inhibit MyoD expression posttranscriptionally. In fact, up-regulation of PC4 in primary myoblasts induces the deacetylation, and hence the inactivation and nuclear export of NF-κB p65, in concomitance with induction of MyoD expression. On the contrary, PC4 silencing in myoblasts induces the acetylation and nuclear import of p65, in parallel with a decrease of MyoD levels. We also observe that PC4 potentiates the inhibition of NF-κB transcriptional activity mediated by histone deacetylases and that PC4 is able to form trimolecular complexes with p65 and HDAC3. This suggests that PC4 stimulates deacetylation of p65 by favoring the recruitment of HDAC3 to p65. As a whole, these results indicate that PC4 plays a role in muscle differentiation by controlling the MyoD pathway through multiple mechanisms, and as such, it positively regulates regenerative myogenesis.

Original languageEnglish
Pages (from-to)5691-5707
Number of pages17
JournalJournal of Biological Chemistry
Issue number7
Publication statusPublished - Feb 18 2011

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology


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