Different domains of the ORL1 and κ-opioid receptors are involved in recognition of nociceptin and dynorphin A

• Published in: FEBS letters Vol. 427; no. 2; pp. 296 - 300
• Main Authors: Lapalu, Sophie, Moisand, Christiane, Butour, Jean-Luc, Mollereau, Catherine, Meunier, Jean-Claude
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 08.05.1998
• Subjects: Animals; CHO Cells; Colforsin - pharmacology; Cricetinae; Cyclic AMP; DAGO, [d-Ala2,N-Me-Phe4,Gly-ol5]enkephalin; DTLET, [d-Thr2,Leu5,Thr6]enkephalin; Dynorphins - chemistry; EKC, ethylketocyclazocine; Gain-of-function protein engineering; hMOR1, hDOR1 and hKOR1, human μ-, δ- and κ-opioid receptor, respectively; hORL1, human opioid receptor-like 1 receptor; Humans; Kinetics; Ligands; M-O, D-O and K-O, hMOR1-(1–151)–hORL1-(134–370), hDOR1-(1–130)- and -hKOR1-(1–141)- chimeric receptors, respectively; Narcotic Antagonists - chemistry; Narcotics - chemistry; Nociceptin; Nociceptin Receptor; Non-opioid–opioid hybrid receptor; nor-BNI, nor-binaltorphimine; O-M, O-D and O-K, hORL1-(1–133)–hMOR1-(152–400), -hDOR1-(131–372) and -hKOR1-(142–380) chimeric receptors, respectively; Opioid peptide; Opioid Peptides - chemistry; Protein Structure, Secondary; Receptors, Opioid - chemistry; Receptors, Opioid - genetics; Receptors, Opioid, kappa - chemistry; Receptors, Opioid, kappa - genetics; Recombinant Fusion Proteins; Structure-function relationship; U-50488, trans-(1S,2S)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]-benzeneacetamide; EKC, ethylketocyclazocine; O-M, O-D and O-K, hORL1-(1–133)–hMOR1-(152–400), -hDOR1-(131–372) and -hKOR1-(142–380) chimeric receptors, respectively; hMOR1, hDOR1 and hKOR1, human μ-, δ- and κ-opioid receptor, respectively; DTLET, [ d-Thr 2,Leu 5,Thr 6]enkephalin; U-50488, trans-(1 S,2 S)-3,4-dichloro- N-methyl- N-[2-(1-pyrrolidinyl)-cyclohexyl]-benzeneacetamide; M-O, D-O and K-O, hMOR1-(1–151)–hORL1-(134–370), hDOR1-(1–130)- and -hKOR1-(1–141)- chimeric receptors, respectively; DAGO, [ d-Ala 2, N-Me-Phe 4,Gly-ol 5]enkephalin; Opioid peptide; Structure-function relationship; nor-BNI, nor-binaltorphimine; Non-opioid–opioid hybrid receptor; hORL1, human opioid receptor-like 1 receptor; Gain-of-function protein engineering
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(98)00452-9

In order to gain further insight into the functional architecture of structurally related G protein-coupled receptors, the ORL1 (nociceptin) and opioid receptors, we have constructed chimeras of ORL1 and μ-, δ- and κ-opioid receptors, and compared their binding and functional properties with those of the parent receptors. We find in particular that a ORL1–κ-opioid (O-K) hybrid construct has retained high affinity for non-type-selective opiate ligands, and has acquired the ability to bind and respond to enkephalins and μ- and/or δ-opioid receptor-selective enkephalins analogs, thus behaving like a `universal' opioid receptor. Most significantly however, whilst the ORL1 and κ-opioid receptors display high binding preference ( K D 0.1 vs. 100 nM) for their respective endogenous ligands, nociceptin and dynorphin A, the O-K chimeric receptor binds both nociceptin and dynorphin A, with high affinity ( K D<1 nM). Together, these data (i) add weight to the hypothesis that the extracellular loops of opioid receptors act as a filter for ligand selection, and (ii) demonstrate that different domains of the ORL1 and κ-opioid receptors are involved in recognition of their endogenous peptide ligands.