Modulation of SRF-dependent gene expression by association of SPT16 with MKL1

Exp Cell Res. 2008 Feb 1;314(3):629-37. doi: 10.1016/j.yexcr.2007.10.004. Epub 2007 Oct 13.


MKL1 (MRTF-A/MAL) is a member of the myocardin-related transcription factor family that plays a key role in the development and differentiation of smooth muscle cells (SMCs) via activation of serum response factor (SRF)-dependent SMC gene expression. MKL1 associates with SRF and stimulates its transcriptional activity. Here, by performing matrix-assisted laser desorption/ionization-time of flight mass spectrometric analysis combined with in vitro glutathione S-transferase pull-down assay, we identified 4 candidate proteins that associate with MKL1 through the N-terminus region of MKL1. SPT16, ATP citrate lyase, nucleolin and radixin were identified, and the physical and functional interactions between MKL1 and SPT16 were examined. SPT16 is a component of the FACT (facilitating chromatin transcription) complex that allows RNA polymerase II to traverse the nucleosomes. SPT16 associates with MKL1 in vitro and in vivo; moreover, SSRP1, another component of the FACT complex, associates with the N-terminus region of MKL1 in vitro. SPT16 synergistically activates the transcriptional activity of MKL1. These results show that the expression of nucleosomal SRF-dependent genes, including the SMC gene, is activated by MKL1 via activation of SRF and recruitment of the FACT complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Citrate (pro-S)-Lyase / genetics
  • Animals
  • Cell Line
  • Cell Nucleus / genetics
  • Cell Nucleus / metabolism
  • Chromosomes / genetics
  • Chromosomes / metabolism
  • Cytoskeletal Proteins / genetics
  • DNA-Binding Proteins / genetics
  • Gene Expression Regulation / genetics*
  • High Mobility Group Proteins / genetics
  • Macromolecular Substances / metabolism
  • Mass Spectrometry
  • Membrane Proteins / genetics
  • Mice
  • NIH 3T3 Cells
  • Nucleosomes / genetics*
  • Phosphoproteins / genetics
  • Protein Binding
  • Protein Structure, Tertiary / genetics
  • RNA-Binding Proteins / genetics
  • Serum Response Factor / metabolism*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcription, Genetic / genetics
  • Transcriptional Activation / genetics*


  • Cytoskeletal Proteins
  • DNA-Binding Proteins
  • High Mobility Group Proteins
  • Macromolecular Substances
  • Membrane Proteins
  • Mrtfa protein, mouse
  • Nucleosomes
  • Phosphoproteins
  • RNA-Binding Proteins
  • Serum Response Factor
  • Supt16 protein, mouse
  • Trans-Activators
  • Transcription Factors
  • nucleolin
  • Ssrp1 protein, mouse
  • radixin
  • ATP Citrate (pro-S)-Lyase