Dephosphorylation of the nuclear factor of activated T cells (NFAT) transcription factor is regulated by an RNA-protein scaffold complex

Proc Natl Acad Sci U S A. 2011 Jul 12;108(28):11381-6. doi: 10.1073/pnas.1019711108. Epub 2011 Jun 27.

Abstract

Nuclear factor of activated T cells (NFAT) proteins are Ca(2+)-regulated transcription factors that control gene expression in many cell types. NFAT proteins are heavily phosphorylated and reside in the cytoplasm of resting cells; when cells are stimulated by a rise in intracellular Ca(2+), NFAT proteins are dephosphorylated by the Ca(2+)/calmodulin-dependent phosphatase calcineurin and translocate to the nucleus to activate target gene expression. Here we show that phosphorylated NFAT1 is present in a large cytoplasmic RNA-protein scaffold complex that contains a long intergenic noncoding RNA (lincRNA), NRON [noncoding (RNA) repressor of NFAT]; a scaffold protein, IQ motif containing GTPase activating protein (IQGAP); and three NFAT kinases, casein kinase 1, glycogen synthase kinase 3, and dual specificity tyrosine phosphorylation regulated kinase. Combined knockdown of NRON and IQGAP1 increased NFAT dephosphorylation and nuclear import exclusively after stimulation, without affecting the rate of NFAT rephosphorylation and nuclear export; and both NRON-depleted T cells and T cells from IQGAP1-deficient mice showed increased production of NFAT-dependent cytokines. Our results provide evidence that a complex of lincRNA and protein forms a scaffold for a latent transcription factor and its regulatory kinases, and support an emerging consensus that lincRNAs that bind transcriptional regulators have a similar scaffold function.

Publication types

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

MeSH terms

  • Active Transport, Cell Nucleus
  • Animals
  • Base Sequence
  • CD8-Positive T-Lymphocytes / metabolism
  • DNA Primers / genetics
  • HeLa Cells
  • Humans
  • Jurkat Cells
  • Macromolecular Substances / chemistry
  • Macromolecular Substances / metabolism
  • Mice
  • Mice, Knockout
  • Models, Biological
  • NFATC Transcription Factors / chemistry*
  • NFATC Transcription Factors / metabolism*
  • Phosphorylation
  • RNA / chemistry*
  • RNA / metabolism*
  • RNA, Long Noncoding
  • RNA, Small Interfering / genetics
  • RNA, Untranslated / chemistry
  • RNA, Untranslated / genetics
  • RNA, Untranslated / metabolism
  • ras GTPase-Activating Proteins / chemistry
  • ras GTPase-Activating Proteins / deficiency
  • ras GTPase-Activating Proteins / genetics
  • ras GTPase-Activating Proteins / metabolism

Substances

  • DNA Primers
  • IQ motif containing GTPase activating protein 1
  • Macromolecular Substances
  • NFATC Transcription Factors
  • NRON long non-coding RNA, mouse
  • RNA, Long Noncoding
  • RNA, Small Interfering
  • RNA, Untranslated
  • ras GTPase-Activating Proteins
  • RNA