Skip to main content

ILF3

Function

RNA-binding protein that plays an essential role in the biogenesis of circular RNAs (circRNAs) which are produced by back-splicing circularization of pre-mRNAs. Within the nucleus, promotes circRNAs processing by stabilizing the regulatory elements residing in the flanking introns of the circularized exons. Plays thereby a role in the back-splicing of a subset of circRNAs (PubMed:28625552). As a consequence, participates in a wide range of transcriptional and post-transcriptional processes. Binds to poly-U elements and AU-rich elements (AREs) in the 3'-UTR of target mRNAs (PubMed:14731398). Upon viral infection, ILF3 accumulates in the cytoplasm and participates in the innate antiviral response (PubMed:21123651). Mechanistically, ILF3 becomes phosphorylated and activated by the double-stranded RNA-activated protein kinase/PKR which releases ILF3 from cellular mature circRNAs. In turn, unbound ILF3 molecules are able to interact with and thus inhibit viral mRNAs (PubMed:21123651, PubMed:28625552).

Post-translational modifications

Phosphorylated at Thr-188 and Thr-315 by PKR in response to certain RNA viruses. This phosphorylation results in the dissociation of ILF2 from the ILF2-ILF3 complex resulting in a cytoplasmic sequestration of ILF3 where it can bind to viral RNAs and impede viral replication.

Methylated by protein arginine N-methyltransferase 1.

Tissue specificity

Ubiquitous.

Cellular localization

  • Nucleus
  • Nucleolus
  • Cytoplasm
  • Nucleus
  • Localizes in the cytoplasm in response to viral infection. The unphosphorylated form is retained in the nucleus by ILF2. Phosphorylation at Thr-188 and Thr-315 causes the dissociation of ILF2 from the ILF2-ILF3 complex resulting in a cytoplasmic sequestration of ILF3. Localized in cytoplasmic mRNP granules containing untranslated mRNAs.

Alternative names

  • Interleukin enhancer-binding factor 3
  • Double-stranded RNA-binding protein 76
  • M-phase phosphoprotein 4
  • Nuclear factor associated with dsRNA
  • Nuclear factor of activated T-cells 90 kDa
  • Translational control protein 80
  • DRBP76
  • MPP4
  • NFAR
  • NF-AT-90
  • TCP80
  • NF90
  • MPHOSPH4
  • DRBF
  • ILF3

Target type

Proteins

Molecular weight

95338Da