A critical role for interleukin-1 receptor accessory protein in interleukin-1 signaling

Eur J Immunol. 1997 Jan;27(1):262-7. doi: 10.1002/eji.1830270139.


Interleukin-1 (IL-1) is a central molecule in inflammation and immune responses whose pleiotropic activities are mediated by the type I IL-1 receptor (IL-1RI). The IL-1RI alone on the cell surface is silent after binding of the ligand. We show that the recently identified IL-1RI accessory protein (IL-1RAcP) converts the silent into a fully functional IL-1RI complex. Although transfection of IL-1RAcP into IL-1RAcP-deficient EL4D6/76 cells did not alter the binding kinetics or dissociation constants of the 125I-labeled IL-1alpha/IL-1RI complex, a very early event, internalization of the activated receptor complex, and a late event, IL-1-stimulated IL-2 production, were successfully restored. Therefore, recruitment of IL-1RAcP is a critical early step in the signaling cascade mediated by the IL-1RI activation complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Endocytosis
  • Interleukin-1 / physiology*
  • Interleukin-1 Receptor Accessory Protein
  • Interleukin-2 / metabolism
  • Mice
  • Proteins / physiology*
  • RNA, Messenger / genetics
  • Receptors, Interleukin-1 / physiology*
  • Signal Transduction
  • Transfection


  • Il1rap protein, mouse
  • Interleukin-1
  • Interleukin-1 Receptor Accessory Protein
  • Interleukin-2
  • Proteins
  • RNA, Messenger
  • Receptors, Interleukin-1