Conformational states of the corticotropin releasing factor 1 (CRF1) receptor: detection, and pharmacological evaluation by peptide ligands |
| |
Authors: | Hoare Sam R J Sullivan Susan K Pahuja Anil Ling Nicholas Crowe Paul D Grigoriadis Dimitri E |
| |
Affiliation: | a Department of Pharmacology, Neurocrine Biosciences Inc., 10555 Science Center Dr., San Diego, CA 92121-1102, USA b Department of Peptide Chemistry, Neurocrine Biosciences Inc., 10555 Science Center Dr., San Diego, CA 92121-1102, USA |
| |
Abstract: | 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 GTPγS) bound by 125I]sauvagine (43 pM, RG); a high affinity state insensitive to GTPγS 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. |
| |
Keywords: | Author Keywords: Corticotrophin releasing factor Ligand binding G-protein-coupled receptor Urocortin Guanine nucleotide Sauvagine Agonist |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|