Nuclear factor-90 of activated T-cells: A double-stranded RNA-binding protein and substrate for the double-stranded RNA-dependent protein kinase, PKR

Biochemistry. 1999 May 11;38(19):6361-8. doi: 10.1021/bi982410u.


NFAT transcription factors play a central role in initiating T-cell activation through the induction of immediate-early T-cell specific genes including interleukin-2 (IL-2). NFAT transcription factors bind to a sequence in the IL-2 enhancer known as the antigen receptor response element 2 (ARRE-2). Multiple proteins exhibiting ARRE-2 binding activity have been isolated, including a heterodimer from stimulated T-cell nuclear extracts consisting of Mr = 90 000 (NF90) and Mr = 45 000 (NF45) subunits. The subunits of this heterodimer have been cloned, and NF90 was found to encode a protein containing two domains that are predicted to form motifs capable of binding to double-stranded RNA. Using in vitro translated polypeptides, we have demonstrated that NF90 specifically binds to double-stranded RNA. Furthermore, NF90 was phosphorylated in a double-stranded RNA-dependent manner likely by the interferon-induced, double-stranded RNA-dependent protein kinase, PKR. The NF90 protein was found to be expressed not only in T-cells, but also in nonimmune HeLa cells. In HeLa cells, the protein was almost exclusively localized to the ribosome salt wash fraction of cell lysates.

MeSH terms

  • Amino Acid Sequence
  • Consensus Sequence
  • DNA-Binding Proteins / metabolism*
  • DNA-Binding Proteins / physiology
  • HeLa Cells
  • Humans
  • Jurkat Cells
  • Lymphocyte Activation
  • Molecular Sequence Data
  • NFATC Transcription Factors
  • Nuclear Factor 45 Protein
  • Nuclear Factor 90 Proteins
  • Nuclear Proteins*
  • Phosphorylation
  • RNA-Binding Proteins / metabolism*
  • RNA-Binding Proteins / physiology
  • Sequence Homology, Amino Acid
  • T-Lymphocytes / metabolism
  • T-Lymphocytes / physiology
  • Transcription Factors / metabolism*
  • Transcription Factors / physiology
  • eIF-2 Kinase / metabolism*


  • DNA-Binding Proteins
  • ILF2 protein, human
  • NFATC Transcription Factors
  • Nuclear Factor 45 Protein
  • Nuclear Factor 90 Proteins
  • Nuclear Proteins
  • RNA-Binding Proteins
  • Transcription Factors
  • eIF-2 Kinase