Ligand-dependent interaction of the aryl hydrocarbon receptor with a novel immunophilin homolog in vivo

J Biol Chem. 1997 Apr 25;272(17):11452-6. doi: 10.1074/jbc.272.17.11452.

Abstract

In an effort to identify regulators of aryl hydrocarbon receptor (AHR) signaling, we have employed the yeast two-hybrid system to screen for human proteins that interact in a ligand-dependent manner with the AHR. After screening 1.4 x 10(6) clones from a human B cell library, two distinct clones were identified that associated specifically with the liganded receptor. No clones were identified that interacted preferentially with the unliganded AHR. One of the ligand-dependent clones, ARA9, encodes a novel 330-amino acid protein with regions of amino acid sequence similarity to the 52-kDa FK506-binding protein known to be associated with the glucocorticoid receptor. Yeast two-hybrid experiments with ARA9 demonstrated a strong interaction with the AHR that is enhanced 11-fold in the presence of the ligand beta-naphthoflavone. In vitro experiments using proteins generated in reticulocyte lysates confirmed this interaction and indicated that ARA9 can be co-immunoprecipitated with the AHR using antisera raised specifically for either the AHR or the 90-kDa heat shock protein. The observation that ARA9 has a high affinity for both the 90-kDa heat shock protein-associated and ligand-activated forms of the AHR suggests that ARA9 is a component of the AHR-signaling pathway in vivo.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Aryl Hydrocarbon Receptor Nuclear Translocator
  • B-Lymphocytes / metabolism
  • Base Sequence
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cloning, Molecular
  • DNA, Complementary / genetics
  • DNA-Binding Proteins / genetics
  • Heat-Shock Proteins / genetics
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Ligands
  • Molecular Sequence Data
  • Nuclear Proteins
  • Protein Binding
  • Proteins*
  • RNA-Binding Proteins
  • Receptors, Aryl Hydrocarbon / agonists
  • Receptors, Aryl Hydrocarbon / metabolism*
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Signal Transduction
  • Tacrolimus Binding Proteins
  • Transcription Factors / metabolism

Substances

  • ARNT protein, human
  • Carrier Proteins
  • DNA, Complementary
  • DNA-Binding Proteins
  • Heat-Shock Proteins
  • IVNS1ABP protein, human
  • Intracellular Signaling Peptides and Proteins
  • Ligands
  • Nuclear Proteins
  • Proteins
  • RNA-Binding Proteins
  • Receptors, Aryl Hydrocarbon
  • Transcription Factors
  • aryl hydrocarbon receptor-interacting protein
  • Aryl Hydrocarbon Receptor Nuclear Translocator
  • Tacrolimus Binding Proteins

Associated data

  • GENBANK/U78521