Rat homolog of mouse interleukin-1 receptor accessory protein: cloning, localization and modulation studies

J Neuroimmunol. 1996 May;66(1-2):41-8. doi: 10.1016/0165-5728(96)00016-1.


A protein which facilitates the binding between interleukin-1 (IL-1) and the type I IL-1 receptor (designated as interleukin-1 receptor accessory protein, IL-1RAcP) has recently been cloned in mouse cells. In the present study, a rat homolog of the mouse IL-1RAcP was isolated from a rat superior cervical ganglion library. The deduced 570 amino acid sequences between rat and mouse IL-1RAcP have > 95% sequence identity to each other with similar predicted signal peptide sequence (20 amino acids), extracellular domain (339 amino acids), a single transmembrane domain (24 amino acids) and a long intracellular domain (187 amino acids). The rat IL-1RAcP has approximately 25% sequence identity to the rat type I IL-1 receptor and a predicted extracellular domain with three immunoglobulin-like loops. RNase protection assays demonstrated that rat IL-1RAcP is expressed in both brain and peripheral tissues with the highest densities present in liver and brain areas such as hypothalamus, cerebral cortex, hippocampus and cerebellum; significantly lower densities were present in lung and in immune tissues such as thymus and spleen. The presence of IL-1RAcP in brain was confirmed by in situ hybridization histochemical studies with a discrete localization present in the dentate gyrus of the hippocampus. The IL-1RAcp was down-regulated in parallel with the type I IL-1 receptor in the liver following endotoxin treatment in rats. These data demonstrating the presence and modulation of a rat homolog of a mouse IL-1RAcP, which is highly expressed in brain and peripheral tissues containing type I rat IL-1 receptor, further suggest the importance of the interaction between the two proteins in rat in modulating the actions of IL-1. On the other hand, the presence of the IL-1RAcP in brain areas which show an absence of type I IL-1 receptors suggests additional functions for this protein in the rat.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Brain / metabolism
  • Cloning, Molecular
  • DNA, Complementary / genetics
  • Endotoxins / pharmacology
  • Histocytochemistry
  • In Situ Hybridization
  • Interleukin-1 Receptor Accessory Protein
  • Mice / metabolism*
  • Molecular Sequence Data
  • Nucleic Acid Hybridization
  • Oligonucleotide Probes
  • Proteins / genetics
  • Proteins / metabolism*
  • RNA, Messenger / metabolism
  • Rats / metabolism*
  • Receptors, Interleukin-1 / genetics
  • Ribonucleases
  • Tissue Distribution


  • DNA, Complementary
  • Endotoxins
  • Il1rap protein, mouse
  • Il1rap protein, rat
  • Interleukin-1 Receptor Accessory Protein
  • Oligonucleotide Probes
  • Proteins
  • RNA, Messenger
  • Receptors, Interleukin-1
  • Ribonucleases

Associated data

  • GENBANK/U48592