The DnaJ-related factor Mrj interacts with nuclear factor of activated T cells c3 and mediates transcriptional repression through class II histone deacetylase recruitment

Mol Cell Biol. 2005 Nov;25(22):9936-48. doi: 10.1128/MCB.25.22.9936-9948.2005.


The calcium-regulated protein phosphatase calcineurin (PP2B) functions as a regulator of gene expression in diverse tissues through the dephosphorylation and activation of a family of transcription factors known as nuclear factor of activated T cells (NFAT). Here we show that NFATc3, in addition to being calcium responsive, is regulated through an indirect recruitment of class II histone deacetylases (HDACs). Specifically, yeast two-hybrid screening with the rel homology domain of NFATc3 identified the chaperone mammalian relative of DnaJ (Mrj) as a specific interacting factor. Mrj and NFATc3 were shown to directly associate with one another in mammalian cells and in vitro. Mrj served as a potent inhibitor of NFAT transcriptional activity within the nucleus through a mechanism involving histone deacetylase recruitment in conjunction with heat shock stimulation. Indeed, Mrj was determined to interact with class II histone deacetylases, each of which translocated to the nucleus following heat shock stimulation. Mrj also decreased NFATc3 occupancy of the tumor necrosis factor-alpha promoter in cardiomyocytes in an HDAC-dependent manner, and Mrj blocked calcineurin-induced cardiomyocyte hypertrophic growth. Conversely, small-interfering-RNA-mediated reduction of Mrj augmented NFAT transcriptional activity and spontaneously induced cardiac myocyte growth. Collectively, our results define a novel response pathway whereby NFATc3 is negatively regulated by class II histone deacetylases through the DnaJ (heat shock protein-40) superfamily member Mrj.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenoviridae / genetics
  • Animals
  • Blotting, Western
  • Calcineurin / metabolism
  • Calcium / metabolism
  • Cell Nucleus / metabolism
  • Cells, Cultured
  • Chromatin Immunoprecipitation
  • Cytoplasm / metabolism
  • DNA, Complementary / metabolism
  • Fibroblasts / metabolism
  • Gene Expression Regulation
  • Gene Library
  • Glutathione Transferase / metabolism
  • HSP40 Heat-Shock Proteins / metabolism
  • HSP40 Heat-Shock Proteins / physiology*
  • Histone Deacetylases / metabolism*
  • Humans
  • Immunoprecipitation
  • Mice
  • Microscopy, Fluorescence
  • Molecular Chaperones / metabolism
  • Molecular Chaperones / physiology*
  • Myocardium / metabolism
  • Myocytes, Cardiac / cytology
  • Myocytes, Cardiac / metabolism
  • NFATC Transcription Factors / metabolism*
  • Nerve Tissue Proteins / metabolism
  • Nerve Tissue Proteins / physiology*
  • Plasmids / metabolism
  • Promoter Regions, Genetic
  • Protein Binding
  • Protein Structure, Tertiary
  • RNA, Small Interfering / metabolism
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Ribonucleases / metabolism
  • Transcription, Genetic*
  • Transcriptional Activation
  • Transfection
  • Tumor Necrosis Factor-alpha / genetics
  • Two-Hybrid System Techniques


  • DNA, Complementary
  • DNAJB6 protein, human
  • HSP40 Heat-Shock Proteins
  • Molecular Chaperones
  • NFATC Transcription Factors
  • Nerve Tissue Proteins
  • RNA, Small Interfering
  • Tumor Necrosis Factor-alpha
  • Glutathione Transferase
  • Ribonucleases
  • Calcineurin
  • Histone Deacetylases
  • Calcium