Conformational states of the corticotropin releasing factor 1 (CRF1) receptor: detection, and pharmacological evaluation by peptide ligands

Peptides. 2003 Dec;24(12):1881-97. doi: 10.1016/j.peptides.2003.09.002.


Previous corticotropin releasing factor 1 (CRF1) receptor characterization has been performed using radiolabeled agonists, which bind predominantly the receptor-G-protein complex. The pharmacological profile of other receptor states, and their abundance, remain poorly characterized. Here we investigated the affinity states of the CRF1 receptor heterologously expressed in Ltk- cells and endogenously expressed in rat cerebellum. In L-CRF1 cell membranes, three agonist affinity states were detected: a very-high affinity receptor-G-protein complex state (eliminated by GTPgammaS) bound by [125I]sauvagine (43 pM, RG); a high affinity state insensitive to GTPgammaS bound by [125I]sauvagine (1.4 nM, termed RO); and a low affinity G-protein-uncoupled state detected by sauvagine displacement of [125I]astressin, a labeled antagonist (120 nM, R). The relative abundance of RG:RO:R was 18%:16%:66%. All three states were demonstrated in rat cerebellum with similar relative abundance (15%:16%:69%). The R state bound CRF with low affinity (270-330 nM), displayed a novel rank order of ligand affinity, and represented the majority of the receptor population in both receptor preparations. This study provides a framework to identify CRF1 receptor conformational states in various receptor preparations.

MeSH terms

  • Amino Acid Sequence
  • Amphibian Proteins
  • Animals
  • Binding, Competitive
  • Cell Line
  • Cell Membrane / metabolism
  • Cerebellum / drug effects
  • Cerebellum / metabolism
  • Corticotropin-Releasing Hormone / antagonists & inhibitors
  • Corticotropin-Releasing Hormone / metabolism
  • Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
  • Humans
  • Iodine Radioisotopes
  • Ligands
  • Molecular Sequence Data
  • Peptide Fragments / antagonists & inhibitors
  • Peptide Fragments / metabolism
  • Peptide Hormones
  • Peptides / metabolism
  • Peptides / pharmacology*
  • Protein Conformation
  • Rats
  • Receptors, Corticotropin-Releasing Hormone / drug effects
  • Receptors, Corticotropin-Releasing Hormone / genetics
  • Receptors, Corticotropin-Releasing Hormone / metabolism*
  • Recombinant Proteins / drug effects
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid


  • Amphibian Proteins
  • Iodine Radioisotopes
  • Ligands
  • Peptide Fragments
  • Peptide Hormones
  • Peptides
  • Receptors, Corticotropin-Releasing Hormone
  • Recombinant Proteins
  • astressin
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • CRF receptor type 1
  • sauvagine
  • Corticotropin-Releasing Hormone