Modulation of SRF-dependent gene expression by association of SPT16 with MKL1.
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.
Kihara
Takanori
T
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan. tkihara@will.dpc.u-tokyo.ac.jp <tkihara@will.dpc.u-tokyo.ac.jp>
Kano
Fumi
F
Murata
Masayuki
M
D001275:ATP Citrate (pro-S)-Lyase / Q000235:genetics; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002875:Chromosomes / Q000235:genetics / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics*; D006609:High Mobility Group Proteins / Q000235:genetics; D046911:Macromolecular Substances / Q000378:metabolism; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D041681:NIH 3T3 Cells; D009707:Nucleosomes / Q000235:genetics*; D010750:Phosphoproteins / Q000235:genetics; D011485:Protein Binding; D017434:Protein Structure, Tertiary / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics; D026362:Serum Response Factor / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics*; D000097796:Nucleolin
D001275:ATP Citrate (pro-S)-Lyase; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D009707:Nucleosomes; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D026362:Serum Response Factor; D015534:Trans-Activators; D014157:Transcription Factors; D000097796:Nucleolin; C511173:Mrtfa protein, mouse; C465039:Supt16 protein, mouse; C070454:Ssrp1 protein, mouse; C071776:radixin